1

APG: Innovative Surfactants Made From Sugar and Fat

Alkyl polyglycosides (APGs) are particularly suited for new formulationconcepts with excellent ecological, dermatological and applicational pro-perties. APGs are the surfactants of the nineties and result from a long-term development of fatty alcohols and their derivatives. The historicaldevelopment of these glucose surfac-tants comprises almost 2 decades at Henkel. APGs are exclusively madeon the basis of regrowable, vegetableraw materials. They display synergisticeffects with classic surfactants andhave a number of interesting, productspecific influences on the hair and the skin.

Alkyl polyglycosides are directly syn-thesized from glucose and fatty alcohol.They are termed the new surfactantgeneration because only few years ago scientists succeeded in developingsynthesis conditions which permit

the production of quantities which areneeded today on a technical scale.

Natural vegetable oils are transformedon their way from the triglyceride to the cosmetic basic material. Fatty acidsand fatty acid methyl esters are basicmaterials derived by splitting or trans-esterification and turn into fatty alcoholsby catalytic high pressure hydration.These fatty alcohols represent a rawmaterial stream for alkyl polyglyco-sides. Within the past 60 years Henkelhas globally become the leading manufacturer of fatty alcohol on a vegetable basis.

In the course of a year, approximately170 billion tons of biomass develop on earth, 5% of which are starch andsugar. Only a small portion of this huge, renewable raw material source is used industrially. Glucose substan-ces are polyhydroxy compounds which are practically available without limits,have a high degree of purity and goodecological and toxicological proper-ties. They are an alternative to ethyleneoxide and may be used as a hydro-philic element for surfactants.(continued on page 16)

No. 12 July 1995

A New Class of CosmeticIngredients

In This Issue Page

A New Class of Cosmetic IngredientsAPG: Innovative Surfactants Made From Sugar and Fat 1

Cosmetic ApplicationsJörg KahreAlkyl Polyglycosides – Multifunctional Ingredients for theCosmetics Industry 2

Skin Compatibility and MildnessBettina JackwerthFatty Alcohol Polyglycosides – a New Surfactant Generation withOutstanding Skin Compatibility 4

BiodegradationJosef SteberThe Biodegradability of Mild Cosmetic Surfactants Based onRenewable Raw Materials 8

Patent SituationBernd FabryAPG – An Overview of the Patent Situation 10

Skin Cleansing and Washing EffectsMathias Rohr/Karlheinz SchraderIn Vivo Tests: Influence of VariousSurfactants on the Skin 12

From Oils, Fats and Starch to Oleochemical Derivatives

Fatty acids

Fatty alcohols

Glucose

Oils and fats

Starch

Fatty acidmethyl esters

Fatty alcoholethoxylates

Alkyl poly-glycosides(APGs)

Guerbetalcohols

Raw Materials Oleochemical Basic Materials Derivatives

Glycerine

Fatty acidderivatives

Partialglycerides

Publisher’s NoteThis Skin Care Forum publication is intended tobe an informal service for cosmetic professionals, researchers, and cosmetic educa-tors/communicators worldwide. While striving tobe accurate, we leave to our select readers allconfirmations and interpretations provided, aut-hored or pub lished by indicated other sources. The Skin Care Forum is distributed free of charge to qualified recipients.

APG, Plantaren and Texapon are trademarks ofHenkel KGaA.

Another basic property of surfactants isof great interest. Although alkyl polygly-cosides cannot always be comparedwith specific thickeners, they have pro-perties that modify the rheological pro-perties. For example, alkyl polyglycosides influence the flowing behavior of highlyconcentrated ether sulfates. This influ-ence is so strong that easily dilutable, well-pumpable, highly concentrated pro-ducts such as Plantaren PS 10 can beoffered on the market (6). Usually, highlyconcentrated ether sulfates show a dis-tinct gel phase at concentrations of 30-45% active substance. The integrationof Plantaren in the formulation leads to products with easy handling during appli-cation. Another interesting application of this property also promotes the deve-lopment of concentrates. For example ashampoo concentrate must have good flowing, dilution and distribution behavior.

From the viewpoint of application, acosmetic ingredient should – in additionto its basic properties – also have fur-ther positive effects perceivable in thefinal formulations. In agents for the cleansing of skin and hair, for example,they should influence the interactionbetween hair fibers and effects on skinand hair. Here, alkyl polyglycosides also display very interesting effects.

Jörg Kahre

Alkyl Polyglycosides –Multifunctional Ingredients for theCosmetics Industry

Alkyl polyglycosides have first beenmentioned in literature in 1893 by Emil Fischer (1). Due to their availabilityon a technical scale and after their market introduction by Henkel underthe brand name Plantaren 1200 UP andPlantaren 2000 UP, alkyl polyglycosideshave been subjected to numeroustests. Their toxicological, dermatologi-cal and ecological behavior can be considered as outstanding (2).

From the pont of view of application,the properties of these surfactants haveprimarily been of major interest (3, 4).Due to their chemical structure (stronghydrophilic part: glucose residue;hydrophobic part: fatty alcohol residue),they have more superior active pro-perties than other nonionic surfactants(Figure 1). Compared to fatty alcoholethoxylates, the foaming power of alkylpolyglycosides is clearly stronger.

1. Surfactant Properties andApplications

In mixtures with conventional surfac-tants, alkyl polyglycosides stabilize thefoam. In combination with acyl gluta-mates, they even produce a foamvolume comparable to that of ether sulfates. This allows the development of particularly mild products with goodor even very good foaming power. The foam structure of alkyl polyglyco-sides differs characteristically from that of other surfactants, for exampleether sulfates (Figure 2).

The cleansing effect of alkyl polygly-cosides as compared to ether sulfatescan be demonstrated impressively inthe following experiment. Pig skin wassoiled with sebum/carbon black andwashed with water under defined con-ditions, a 3% ether sulfate solution and 3% alkyl polyglycoside solution;the surfactant content refers to theactive substance content. A grey shadewas then determined and evaluatedwith the aid of digital image processing.The results revealed that at this lowactive content of surfactant only Plan-taren 1200 UP provided a wrinkle- andpore-deep cleansing.

This result is of special interest for thedevelopment of facial cleansers andeye makeup removers. It is also impor-tant for shower gels and shampoos,since it is possible to reduce the activecontent without loosing the cleansingpower.

On hair it causes an increase of the dry combing work. Short to medium-length as well as very fine hair is alwaysproblematic. In order to arrange ahairdo in the dry state which has stand,volume, hold and body, the interac-tions between the hair fibers must beincreased. Measurements on hairstrands show that alkyl polyglycosidesincrease their dry combing work. There-fore, alkyl polyglycosides are interestingingredients for the formulation of pro-ducts for fine hair. Apart from this, thesynergistic effect between alkyl poly-glycosides and cationic substances can be exploited to obtain particularlypositive effects. On fine hair cationicproducts can lead to excessive load.However, they are necessary in order to reduce the wet combing work.

2

Cosmetic Applications

Figure 1Plantaren – Alkyl Polyglycosides

H

H

O

O

O

O

H

HO

O

O

Plantaren 1200 Lauryl Polyglucose 12-16Plantaren 2000 Decyl Polyglucose 8-16

Dr. Jörg Kahre is achemist and specia-lizes in the sector of cosmetic wavingagents and hair ana-lysis. Since 1992 hehas been head of theproduct developmentof new ingredients for hair treating agents.He furthermore dealswith new applicationareas of alkyl poly-glycosides.

Figure 2 Foam Structures of Alkyl Polyglycosides by Comparison with a ClassicStandard Surfactant (30 times enlarged after 15 minutes)

Standard SurfactantSodium Laureth Sulfate – foam bubbles

New Product TypeLauryl Polyglucose – foam bubbles

• coarse-bubbled • polyedric• dry • unstable

• fine-bubbled • round• wet • stable

By means of the synergistic effect between alkyl polyglycosides and spe-cific cationic raw materials, the requiredconcentration of cationic substancesmay be optimized.

2. Alkyl Polyglycosides in Non-surfactant Formulations

The synergism with cationic surfactantsas well as the emulsifying property ofalkyl polyglycosides, in particular of the longer chain APGs, enables theirapplication in O/W emulsions. Suchemulsions can be used as rinse-off orleave-on-intensive conditioners for hair aftertreatment (6, 7).

Their use in emulsions, the pH stabilityin the alkaline range, the easy combina-tion with cationic substances and thesurface activity also allow the applica-tion of alkyl polyglycosides in hair dyes.

Another property of alkyl polyglycosidesis that they increase the tensile strengthof hair strands, which also speaks infavor of their use in dyes. They may fur-thermore be applied in waving agents.With the alkaline solubility it could beproved that alkyl polyglycosides may be utilized for the production of mildwaving lotions with good reshapingeffect (8). The alkaline solubility of hairmeans that under defined conditionscold-waved hair is treated with a caus-tic soda solution. The mass loss of the hair during this alkaline treatment is determined gravimetrically. It is ameasure for the degree of reductiveand oxidative damage to the hair.

Waving agents are products for thelong-term styling of hair. Blow-dryinglotions, styling foams, gels and waxes,in contrast, are intended for short-termreshaping and fixing of the hair. Thisrequires film-forming properties of theingredient. In addition to the traditionallyused film-forming polymers, proteinhydrolysates and alkyl polyglycosidesalso lead to film formation. The hair setting effects of a combination of alkylpolyglycosides with protein hydroly-sates are comparable to those of a 2%polyvinyl pyrrolidone solution (6, 7).

The applications of alkyl polyglycosidesdescribed so far concerned agents forthe cleansing and care of skin and hair.On account of the excellent mucosacompatibility, the good toxicologicalvalues as well as the good foamingbehavior, alkyl polyglycosides can also be used for dental care both intoothpastes and mouthwashes or in“two in one” gels.

These examples demonstrate that alkylpolyglycosides are cosmetic ingredientshaving a very broad range of appli-cation. With the increasing availability of alkyl polyglycosides, further new formulation concepts will become possible in the future and the range ofapplications will become even broader,thus opening a promising future for alkyl polyglycosides.

Summary

As shown in Figures 3a and 3b, alkylpolyglycosides are modern, multi-func-tional ingredients for the cosmeticsindustry. Their application spectrumclearly extends beyond that of surfac-tants. Alkyl polyglycosides are interest-ing and promising ingredients whosedevelopment potential is far from being exhausted. Many interesting

product innovations in cosmetics may be expected for the future, andalkyl polyglycosides will certainly make a major contribution.

Bibliography(1) Fischer E.; Ber. 26 (1893) 2400(2) Matthies W.H.; Krächter H.U.; Steiling, W.;Weuthen M.; Skin and Mucous Membrane Compatibility of Alkyl Polyglycosides (APG); In: 18th IFSCC International Congress; The Cosmetic Image – A Mosaic of Biosciences;Vol. 4; IFSCC (1994) 317-323(3) Busch P.; Hensen H.; Tesmann H.;Alkylpolyglycoside – eine neue Tensidgenerationfür die Kosmetik; Tenside Surfactants Deterg. 30(1993) 116-121(4) Busch P.; Hensen H.; Krächter H.U.;Tesmann H.; Alkyl Polyglycosides – Their Use in Cosmetics; Cosmetics and Toiletries Manu-facture Worldwide 74 (1993) 123-130(5) Salka B.; Alkyl Polyglycosides: Properties andApplications; Cosmetics & Toiletries 108, No. 3(1993) 89-94(6) Busch P.; Hensen H.; Kahre J.; Salka B.;Tesmann H.; Alkylpolyglycoside – neue Anwen-dungen in Haarbehandlungsmitteln; In: Verlag fürchemische Industrie (ed.): 40. Jahrestagung derSEPAWA (1993) 23-29(7) Busch P.; Hensen H.; Kahre J. Tesmann H.;Alkyl Polyglycosides – A New Cosmetic Conceptfor Mildness and Care; Agro-Food-Industry hi-tech 9/10 (1994) 23-28(8) Kahre J.; Goebels D.; Einflüsse von Tensidenauf die Wirkung von Wellmitteln am Haar; In: Verlag für chemische Industrie (ed.): 41. Jahrestagung der SEPAWA (1994) 36-41

3

Figure 3b APG – A Multifunctional Cosmetic Ingredient (II)Figure 3a APG – A Multifunctional Cosmetic Ingredient (I)

Properties (Hair care products)

• emulsifying

• setting properties• curl retention

• no hydrolysis at alkaline pH-value

• improves tensile strength of hair

• modifies interaction of dry hair

• cleansing power

Use

emulsions:• hair rinses• hair colours

• setting lotions• styling gels

• permanent wave formulations

• volume and body formulations

• shampoos for fine or damaged hair

• pore and wrinkle-deep cleansing

Properties

• extremely mild

• readily biodegradable

• good foamer

• viscosity modifier

• reduces peak viscosity of FAES pastes (e.g. Plantaren PS 10)

Use

main or co-surfactant for all kind of cleansing preparations:

• shampoo

• shower bath

• foam bath

• facial wash

• shampoo concentrates

Bettina Jackwerth

Fatty Alcohol Polyglycosides – a New Surfactant Generation withOutstanding Skin Compatibility

1. Introduction

For cosmetics developers fatty alcoholpolyglycosides represent a new surfac-tant generation which is marked by a combination of desired applicationproperties with good environmental compatibility and an outstanding derma-tological compatibility. The cleansingproperties of surfactants are more orless linked with undesired effects onskin (1). Owing to changing consumerhabits and thus altered demands onskin cleansing agents over the lastdecades, an improved compatibility has become more and more important.This raises new possibilities for particu-larly skin-friendly surfactants such asfatty alcohol polyglycosides (2).

This article describes the outstandingskin compatibility of the fatty alcoholpolyglycosides, using the example of Plantaren 1200 (lauryl polyglucose, base: C12-C16 fatty alcohol), Plantaren 2000(decyl polyglucose, base: C8-C16 fattyalcohol) and Plantaren PS 10 (lauryl polyglucose and sodium laureth sulfate). The example of sodium laureth sulfate(sodium lauryl ether sulfate with 2 EO)reveals how the skin compatibility ofconventional surfactants can be improved by adding fatty alcohol poly-glycosides.

2. Methods for the Examination of the Skin Compatibility of Surfactants

In vitro tests as well as in vivo studieson human skin play a role in evaluatingthe compatibility of surfactants and sur-factant mixtures. The chicken egg test(HET-CAM) is presented as an examplefor in vitro tests. For in vivo methods,the modified Duhring Chamber test, the arm-flex wash test and a consumertest are described.

2.1 In Vitro Tests

Chicken Egg Test (HET-CAM)The local irritation potential of the testsubstances can be evaluated compara-tively on the chorionallantois membrane(CAM) of incubated chicken eggs. Thechicken egg test also serves as an

alternative method for the evaluation of mucosa compatibility. A mixture ofspecific fatty alcohol ether sulfates(Texapon ASV) is used as a referencesubstance for this method. The irritationpotential of the test substances is divided by the irritation potential of Texa-pon ASV. The resulting irritation ratio Qserves as an evaluation measure formucosa compatibility (3).

2.2 In Vivo Tests

There are standardized methods for thein vivo evaluation of skin compatibility;contact time, contact frequency and type of application are graduallyadjusted to practical application con-ditions (Figure 1).

Modified Duhring Chamber TestThe occlusive, single application Duhring Chamber Test, modified accord-ing to the Soap Chamber test deve-loped by Frosch and Kligman (4), isabove all suitable for the screening ofsurfactants. By means of specific plas-ters with aluminum chambers, the diluted test substances are applied for24 hours on the backs of 20 test sub-jects. The resulting findings, i.e. ery-thema, squamation and swelling, areevaluated according to a defined sys-tem up to 72 hours after removal of theplaster and expressed as irritation scoreper substance. Sodium laureth sulfate(1% active substance) is used as a

reference substance and referencequantity for the determination of therelative irritation scores of the test samples (Figure 3, 4). This anionic standard surfactant is widely used in all types of washing and cleansing pro-ducts and is regarded as having a goodskin compatibility. This method onlytakes into consideration effects whichcan be assessed objectively and is considered to be very skin-friendly.

For the interpretation of the findings itmust be considered that the modifiedDuhring Chamber test for “rinse off”products is carried out under intensifiedtest conditions. Since the contact timeis clearly longer than during normal application and since the test conditions are occlusive the superficial skin layersswell, thus making penetration of thesubstances into the skin easier. There-fore, the results of this test systemshould only be interpreted together with an evaluation of the compatibility in an application-oriented test.

Arm-Flex Wash TestThe arm-flex wash test represents a standardized method for the application-oriented screening of surfactants andsurfactant formulations. Under con-trolled conditions 20 test subjects washtheir sensitive arm flex with the testsamples. Since the washing occurstwice a day over 2 weeks (weekendsexcluded) and no care product is applied in the application area, test con-ditions are also intensified so that highlycompatible test substances can also be distinguished. In addition to visible findings such as erythema and squama-tion, the arm-flex wash test also eva-luates subjective findings, e.g. itching,prickling, burning and tension (1). Thesubjective effects are registered bothbefore and during washing. As in theDuhring Chamber test, on the basis ofindividual evaluations for every productan irritation score is determined for the

4

Skin Compatibility and Mildness Biologist Bettina Jackwerth is in charge of cosmetic productsat Henkel's Depart-ment of Dermatology.Major emphasis of herwork in dermatologylies in a consultantactivity with regard tothe optimization offormulations underthe aspects of skincompatibility and thedemonstration of product effects on the skin.

Figure 1 Test Strategy

Test strategy for the dermatological examination of surfactants, surfactant mixtures and finished products with step by step approximation to practical application conditions.

Strategy

laboratory model

application situation

Method

Modified Duhring Chamber test

Arm-flex wash test

Consumer test

Test principle

single, long-term occlusive application

repeated open application underintensified test conditions

repeated application under normal test conditions

different criteria. Again sodium laurethsulfate (10% active substance) is usedas a reference substance.

The expressiveness of the arm-flexwash test and the differentiation of thetest substances is still improved bymeans of physical measuring techni-ques. Before the first and after the last washing the transepidermal waterloss (TEWL) is measured with an eva-porimeter as a measure of the barrierdamage. Both visible and invisibledamages of superficial skin layers canbe quantified in this way.

The visual evaluation by the test conduc-tor, the subjective evaluation of the testsubjects and the physical-quantitativemeasurement, allow precise statementsabout the effects of the formulations on skin.

Consumer TestThe consumer test represents the laststep prior to product launch. At least 50 test subjects apply the end product(e.g. shower gel or shampoo), at homeunder usual application conditions over a test period of 6 weeks. This testreveals how the good compatibility of the fatty alcohol polyglycosides isexperienced by the consumer underpractical conditions. At the end of thetest period, the application propertiesand the skin compatibility of the pro-ducts are documented with the aid of a questionnaire.

3. Test Results

We investigated the following test samples to evaluate the compatibility of Plantaren products as well as that of surfactant mixtures with Plantaren:

SurfactantsFormulation 1 (F1):

Sodium laureth sulfateFormulation 2 (F2):

Lauryl polyglucose (Plantaren 1200)Formulation 3 (F3):

Decyl polyglucose (Plantaren 2000)Formulation 4 (F4):

Sodium laureth sulfate (and) laurylpolyglucose (Plantaren PS 10)

Mixtures with Plantaren 1200Formulation 5 (F5):

Sodium laureth sulfate (3 parts) andlauryl polyglucose (1 part)

Formulation 6 (F6):Sodium laureth sulfate (1 part) andlauryl polyglucose (1 part)

Formulation 7 (F7):Sodium laureth sulfate (1 part) andlauryl polyglucose (3 parts)

Mixtures with Plantaren 2000Formulation 8 (F8):

Sodium laureth sulfate (3 parts) anddecyl polyglucose (1 part)

Formulation 9 (F9):Sodium laureth sulfate (1 part) anddecyl polyglucose (1 part)

Formulation 10 (F10):Sodium laureth sulfate (1 part) anddecyl polyglucose (3 parts)

Chicken Egg TestIn this test system lauryl polyglucoseshows an outstanding compatibility.Lauryl polyglucose reaches the irrita-

tion potential of Texapon ASV (5% AS)(Figure 2) only at a concentration of40% AS. In contrast to this the irrita-tion potential of decyl polyglucose (no figure) is higher than that of the reference substance at all concentra-tions. Therefore lauryl polyglucoseshould be used for products whichclaim good mucosa compatibility.

Modified Duhring Chamber TestFigures 3 and 4 represent the results for erythema formation. Squamationshows an analogous behavior. The testsamples did not cause swellings.

In a first step mixtures of sodium laurethsulfate with decyl polyglucose werecompared with decyl polyglucose(Figure 3, test concentration 1.4% AS).If sodium laureth sulfate (F1) is substi-tuted step by step with fatty alcoholpolyglycoside (F8, F9, F10), this leadsto a clear improvement of skin compa-tibility, which is expressed in the reduc-tion of the relative irritation scores(Figure 3). A mixing ratio of three partssodium laureth sulfate with one partdecyl polyglucose (F8) improves theskin compatibility by approx. 40 per-cent points. A mixing ratio of one partsodium laureth sulfate with three partsdecyl polyglucose (F10) reduces the irritation potential of the mixture ascompared to sodium laureth sulfate by approx. 97% points. The relative irritation potential of pure Plantaren (F3)is only 8% of the irritation potential of sodium laureth sulfate with the sameconcentration.

Furthermore, the Plantaren products1200 and 2000 were compared in 1%AS and 3% AS concentrations (Figure4a, 4b). For both concentrations the irritation potential is clearly lower thanthat of the reference substance sodiumlaureth sulfate (1% AS). Consequently,the Plantaren products display an out-standing skin compatibility for surfac-tants. Unlike the chicken egg test, thistest model does not reveal a cleardependence of the compatibility uponthe chain length of the alkyl residue.

Plantaren PS 10 is a commercial mixture which consists of a highly con-centrated ether sulfate as a main component with a medium-chain fattyalcohol polyglucoside as a co-surfac-tant (5). This mixture was also examined with a concentration of 1% and 3% ASin the modified Duhring Chamber test(Figure 4c). As expected, this mixturewith a concentration of 1% AS shows a better skin compatibility than puresodium laureth sulfate. With three times

5

Figure 2 HET-CAM Test

Irritation potential represented as irritationratio Q for Plantaren 1200 (lauryl polyglu-cose, orange bars) in relation to TexaponASV (mixture of specific fatty alcohol ethersulfates, yellow bars) on the chorionallan-tois membrane.

Irritation ratio Q

Figure 3 Modified Duhring ChamberTest Erythema Formation

Improvement of skin compatibility ofsodium laureth sulfate mixed with decylpolyglucose using the example of erythemaformation. Relative irritation score as compared to pure sodium laureth sulfate(1% AS =100%). Test concentration 1.4% AS; n = 20

Relative irritation score (%)

50 40 30 20 10 5 50

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

F1 F8 F9 F10 F30

20

40

60

80

100

120

140

Test concentration (% AS)

the AS content, the irritation potential is only 17% higher than that of sodiumlaureth sulfate with 1% AS.

Arm-Flex Wash TestIn the arm-flex wash test, lauryl poly-glucose, decyl polyglucose as well assurfactant mixtures from sodium laurethsulfate with lauryl polyglucose (F5) andsodium laureth sulfate with decyl poly-glucose (F8), with a ratio of 3 :1 each,were examined at a test concentrationof 10% AS. Pure sodium laureth sulfate(10% AS) was used as a reference. The irritation score and /or the trans-epidermal water loss was put in relationto the reference in order to ensure comparability.

Figure 5 illustrates the relative irritationscore for erythema formation (Figure 5a)and squamation as an indicator for thedrying of skin (Figure 5b), the relativeirritation score for the sensorial para-meters (Figure 5c) as well as the relativechange of the transepidermal waterloss (Figure 5d). The substitution of25% sodium laureth sulfate with a fattyalcohol polyglucoside (F5, F8) leads to a reduction of the visible findings,erythema and squamation, by approxi-mately 20 to 40%. The skin protectiveeffect can be recognized even moreclearly from the subjective, negativesensations. Here, improvements byapproximately 70% can be achieved.As compared to pure sodium laurethsulfate, the Plantaren products (F2, F3)reduce erythema formation by 80% to90% and squamation by 70 to 90%.Subjective negative sensations dis-appear almost completely. The trans-epidermal water loss (Figure 5d) is ameasure of the barrier damage and therefore of the potential drying of skin.It is reduced by approx. 5 to 20%through addition of fatty alcohol poly-glucoside to sodium laureth sulfate (F5,F8). The pure Plantaren products 1200and 2000 achieve a significant reduc-tion of the barrier damage (p < 0.001) by approx. 65 to 75% (F2, F3). This isan outstanding result for washing-activesubstances.

The number of negative sensations du-ring washing is represented in Figure 6.Subjective negative sensations duringapplication of a product provide infor-mation about the skin sensitivity whichis increased by the surfactant appli-cation to varying extents in this testsystem. Over the entire test period, thetest subjects describe negative sensa-tions in 74 washings during applicationof the reference substance sodium laureth sulfate. A substitution of 25%sodium laureth sulfate with fatty alcoholpolyglycoside (F5, F8) leads to a reduc-tion of the skin damage and thus theskin sensitivity so clearly that negativesensations are described only in 19and /or 24 washings. For pure Plan-taren products there are almost no subjective findings throughout the entiretest period, in spite of intensified testconditions.

The positive influence of fatty alcoholpolyglycosides on the compatibility ofsodium laureth sulfate is also reflectedin the smaller number of test subjectswho stopped the test early (Figure 7a).Through substitution of 25% sodiumlaureth sulfate with a Plantaren productit is already reduced by 50% (Figure 7a,F5 and F8 compared to F1). In thecase of pure fatty alcohol polyglycosi-des, no test subject stopped the testwithin the entire application period of 14 days in spite of intensified conditions(F2, F3).

6

Figure 4 Modified Duhring ChamberTest Erythema Formation

Relative irritation potential of Plantaren 1200(a), Plantaren 2000 (b) and Plantaren PS 10(c) in a concentration of 1% AS and 3% ASas compared to sodium laureth sulfate in 1% AS using the example of erythema formation; n = 20

a) Plantaren 1200

Relative irritation score (%)

b) Plantaren 2000

Relative irritation score (%)

c) Plantaren PS 10

Relative irritation score (%)

Figure 5 Arm-flex Wash Test

Improvement of the skin compatibility of sodium laureth sulfate mixed with fatty alcohol polyglucosides. Relative irritation score as compared to sodium laureth sulfate (= 100%) using the examples of erythema formation (a), squamation (b), sensoric parameters (c) andtransepidermal water loss (TEWL) (d). Test concentration 10% AS; n = 20

a) erythema formation b) squamation

Relative irritation score (%) Relative irritation score (%)

c) sensoric parameters d) transepidermal water loss (TEWL)

Relative irritation score (%) Δ Relative TEWL (%)

1% AS 3% AS

100

80

60

40

20

0

1% AS 3% AS

100

80

60

40

20

0

1% AS 3% AS

120

0

20

40

60

80

100

140

020406080

100120

F5F1 F8 F2 F3

F1 F5 F8 F2 F30

20406080

100120

F1 F5 F8 F2 F30

20406080

100120

E1 E5 E8 E2 E30

20406080

100120

* *

*significant atp < 0.001

In accordance with the better compa-tibility of the mixtures (F5, F8) as compared to pure sodium laureth sul-fate, the test was stopped at a latertime during the two-week test phase(Figure 7b). While 12 test subjects stopped the application of sodium laureth sulfate after 15.8 washings onaverage, the application of the surfac-tant mixtures was stopped by only 6(F8) and /or 7 test subjects (F5) after anaverage of 17 to 18 washings.

To sum up, it can be stated that thisapplication-oriented but intensified testmodel proves the outstanding skincompatibility of the pure Plantaren pro-ducts in all three evaluation methods,i.e. visually, physically and subjectively.

We were able to demonstrate the rele-vance of the results from the tests withsurfactant mixtures and pure fatty alco-hol polyglucosides for the practicalapplication situation in consumer testswith shower gel and foam bath formula-tions. The formulations with Plantarenachieved the best results with respectto a general compatibility and the sub-jective evaluation by the test subjects.

4. Summary

In mixtures, Plantaren products as sub-stitutes of sodium laureth sulfate lead toa significant reduction of the irritationpotential of the conventional surfactantson human skin. In different test models,visible skin damage is clearly reducedby the application of the mixtures. Aneven stronger improvement is obtainedwith respect to subjective negative sensations. The measurement of thetransepidermal water loss objectively

demonstrates that the skin barrierdamage is smaller when fatty alcoholpolyglycosides are added. This mini-mizes the drying of skin, above all in thecase of repeated washing. In correlationto this, other tests show that the skinmoisture is less impaired by the pro-ducts Plantaren 1200 and 2000 and /ora mixture of sodium laureth sulfate with decyl polyglucose (F8) than by the pure sodium laureth sulfate (5).

Fatty alcohol polyglycosides, a newgeneration of non-ionic surfactants,offer the possibility to clearly improvethe compatibility of cosmetic cleansingproducts. This is particularly importantwhere the skin of the user must not bedamaged in addition to existing internaland external influences. This is of spe-cial importance for aged skin as well asfor baby skin. Furthermore, it is relevantfor skin changes where the dermato-logist often recommends special cos-metic agents, e.g. mild formulations selected from the cleansing sector. Fatty alcohol polyglycosides are not onlyintended to minimize further damage to the skin. As can be seen from theimprovement of the subjective, negativesensations, formulations on the basis offatty alcohol polyglycosides also show a better compatibility on pre-damagedskin. Fatty alcohol polyglycosides aretherefore above all suitable for the for-mulation of products for sensitive skinthat claim “outstanding skin compati-bility”. The constantly growing numberof persons with sensitive skin raisesnew possibilities for the future.

For the developer it is an additionaladvantage that the outstanding compa-tibility of the Plantaren products can be combined with a reduced activesubstance content in the end productwhile maintaining the same foamvolume and /or the same skin cleansingcapacity (5). For the respective producttype and the specific requirements, e.g. with respect to skin or mucosacompatibility, the ideal surfactant combination must be found and its properties must then be examined inappropriate test systems.

Bibliography(1) Jackwerth, B.; Krächter, H.-U.; Matthies, W.;Dermatologische Prüfmethoden zur Optimierungmilder Tensidpräparate; Parfümerie undKosmetik 3 (1993)134-141(2) Fabry, B.; Tenside, Vergangenheit, Gegenwartund zukünftige Entwicklungen; SÖFW Journal 7(1994) 378-386(3) Sterzel, W.; Bartnik, F.G.; Matthies, W.; Käst-ner, W.; Künstler, K.; Comparison of Two in Vitroand Two in Vivo Methods for the Measurementof Irritancy; Toxic. in Vitro 4 (4/5) (1990) 698-701(4) Frosch, P.; Kligmann, A. M.; The Soap Chamber Test; J. Am. Acad. Dermatol.1 (1979) 35-41(5) Busch, P.; Hensen, H.; Kahre, J.; Salka, B.;Tesmann, H.; Alkylpolyglycoside – Neue Anwen-dungen in Haarbehandlungsmitteln; SEPAWA-Jahrestagung (1993); Tagungsband 23-29(6) Busch, P.; Hensen, H.; Tesmann, H.;Alkylpolyglycoside – Eine neue Tensidgenerationfür die Kosmetik; Tenside Surfactants Det. 30(1993) 116-121

7

Figure 7 Arm-flex Wash Test

Improvement of skin compatibility of sodium laureth sulfate mixed with fatty alcohol poly-glucosides. Figure 7a shows the number of test subjects who stopped the test early. Figure 7bshows the average number of washings per test subject group after which the test was stopped. The mixtures of sodium laureth sulfate with fatty alcohol polyglucosides (F5, F8) can on average be applied for a longer time before the test is stopped. In the case of the pure Plantaren products (F2, F3) the test is carried out over 14 days by all volunteers.Test concentration 10% AS; n = 20

a) Number of test subj. who stopped test early b) Number of washings

F1 F5 F8 F2 F30

2

4

6

8

10

12

14

F1 F5 F8 F2 F30

5

10

15

20

Figure 6 Arm-flex Wash Test

Improvement of skin compatibility ofsodium laureth sulfate mixed with fattyalcohol polyglucosides using the exampleof the number of negative sensationsduring application.Test concentration 10% AS; n = 20

Number of negative sensations during application

F1 F5 F8 F2 F30

20

40

60

80

Josef Steber

The major part of cosmetic productingredients reach the environment aftertheir use. This happens because they are destined to reach the wastewater as “rinse-off” products or because at leasta portion of them is washed off duringbody cleansing. Due to the physico-chemical and biological properties of chemical compounds they spread in the various environmental areas such as surface waters, sediments, sludge, soils, etc. If not removed by degradation pro-cesses, they may have a toxic influenceon living organisms in the environment.A far-sighted evaluation of potentialecological hazards should be based on the knowledge of fate- and effect-relevant properties of the product ingre-dients, i.e. particularly of their biodegra-dability and ecotoxicity of the productcomponents. From these data and bytaking the concrete environmentalsituation into account (e.g. amount of products used, sewage treatment situa-tion, effluent dilution factors in rivers,etc.) an estimation of the predictedenvironmental concentration (PEC) and the predicted (ecotoxicological) no effect concentration (PNEC) can be made.Mathematically expressed a hazard isgiven when the ratio PEC/PNEC is ≤ 1.No hazard is to be anticipated if PEC < PNEC (1).

Primary and UltimateBiodegradation

Biodegradation is the most importantmechanism which is responsible for theirreversible removal of organic com-pounds such as surfactants from aque-ous and soil environments. Biodegrada-tion is a multistep process starting withthe transformation of the parent com-pound into a first degradation product(primary degradation) and forming, in the end, mineralization products (carbon dioxide, water) and bacterial biomass(ultimate or total degradation) (2).

The primary degradation of a surfactant, which is of significance from an ecologi-cal point of view, as well as its ultimatebiodegradation, which plays an impor-tant long-term role in the environment,can be assessed by standardized andinternationally applied test methods(OECD, EC), see Figure 1. Normally thesurface-activity and thus the ecotoxicityof a surfactant is significantly reduced in

the primary degradation steps. The primary degradation of many surfactants can be proven by the application ofspecific analytical procedures. Theseanalytical methods are often applicableto the whole group of chemically relatedsubstances. Examples of these are theMBAS (methylene-blue active sub-stance) and BiAS (bismuth active sub-stance) loss for anionic and nonionicsurfactants. The so-called DSBAS(disulfin-blue active substance) methodis another analytical method for cationicsurfactants. With regard to alkyl poly-glycosides, which is a very importantsurfactant group for cosmetic products, there is no specific analysis group proce-dure. Therefore, an evaluation of thebiological degradation behavior of thissurfactant group, which is completely

based on renewable raw materials,strictly occurs by determining the ulti-mate biodegradability. However, thedegradation rates associated with theprimary degradation of a surfactant arehigher than those associated with the ultimate degradation.The ultimate degra-dation is measured by so-called sumparameters which are not specific forthe particular substance. Examples ofthese sum parameters are the develop-ment of CO2 or the oxygen demanddue to the mineralization process(Biological Oxygen Demand, BOD) orthe reduction of the dissolved organiccarbon (DOC) of the test compound.

Test Procedures for DeterminingBiodegradability

A determination of the degradability ofsurfactants usually starts with screeningtests which, due to their stringency, aresimple but informative test methods. Under the given conditions of the OECD tests for ready biodegradability, whichalso comprise the closed bottle test (OECD 301 D), another strict test proce-dure, and the modified OECD screeningtest (OECD 301 E) many surfactants based on renewable raw materials prove to be readily biodegradable (Figure 2).Examples of this are the following

8

The Biodegradability of MildCosmetic Surfactants Based onRenewable Raw Materials

Figure 1 Standardized Procedures for Determining the Biodegradability of Substances

Dr. Josef Steber is head of Henkel’sEcological Depart-ment. His researchtopics include experimental testsand evaluations ofthe biodegradabilityof cosmetic ingredients.

Screening tests

� single addition of test substance� test substance is C source� duration of test up to 4 weeks� stringent assessment

OECD confirmatory test: demand ≥ 80% (MBAS, BiAS)

OECD tests for ready biodegradability:� closed bottle test: ≥ 60%

O2 consumption� modi. OECD screen. test: ≥ 70%

carbon removal*� CO2 evolutions test: ≥ 60%

CO2 formation

Sewage treatment plant simul. tests

� continuous dosage of test substanceand synthetic wastewater

� retention time: 3-6 hours� evaluation close to reality

OECD screening test: demand ≥ 80% (MBAS, BiAS)

Coupled units test: measurement of DOC removal [%]

Charac-teristics

Examples Primary degradation(relevant for detergent legislation: anionic and nonionic surfactants)

Ultimate degradation(relevant for Chemicals Law, EC classification “hazardous for the environment”)

* pass value for “ready biodegradability”

outflowinflow

groups of surfactants: alkyl polyglycosi-des, fatty alcohol sulfates, fatty alcoholether sulfates and fatty alcohol ethoxy-lates. As agreed internationally, suchsubstances are easily and ultimatelybiodegraded, namely in sewage treat-ment plants and in surface water.

This thesis was totally confirmed byinvestigations into alkyl polyglycosidesby means of the coupled units test(OECD 303 A). This is a further, interna-tionally applied test system which simu-lates the degradation situation in a biological sewage treatment plant. Thecoupled units test requires a continuous dosage of test substances and nutrients and thus represents a realistic model totest the biodegradability of substancesin the competitive situation with a sur-plus of readily degradable substances(“synthetic wastewater”). Here, an ulti-mate biodegradation of approximately90% can be shown under realistic, yet rather conservative conditions by current standards of wastewater treatmentpractice (Figure 2). Alkyl polyglycosidesremain in the plant for an average of 3hours, while under practical conditions6-12 hours or more are common for modern plants. This high ultimate degra-dation value means that alkyl polyglyco-side surfactants in the wastewater arealmost completely transformed intoproducts which are reintegrated into thenatural circuit (carbon dioxide, bacterialbiomass). Due to their lower bacteriadensity substances are degraded atlow speed in a receiving stream. Sincethe same degradation processes take place in a receiving river as in thesewage treatment plant, there is princi-pally no doubt that a complete andready biodegration of materials whichhave not yet been degraded in thesewage treatment plant is achieved inthe surface waters provided that theyare “readily degradable compounds”.

Metabolite Test

To improve the evaluation and docu-mentation of the completeness of theultimate biodegradation of surfactantsand other chemical compounds, furthertests are performed on such importantcosmetic ingredients as alkyl polyglyco-sides. These tests are more elaboratethan the broadly applied standardizedtests and are sometimes very com-prehensive. Despite positive resultsachieved in the above mentioned screening and simulation tests the con-clusion to be drawn about a ready and ultimately complete degradation ismainly based on the practical experi-ence gained from many chemical

compounds tested and assessed in the past. Nevertheless, the questionalways comes up again if organic material which was not degraded in the test period might contain smallamounts of intermediates with pro-perties which are unknown and thusperhaps critical for the environment. On the experimental basis of the coupled units test the “test to detectstable degradation intermediates (metabolite test)”, which was developedby us, helps answer these questions(2). In contrast to the sewage treatmentplant simulation test (OECD 303 A) the wastewater, which is treated in thetest plant, is reused each day as aninfluent after feeding in a concentrate of the test substance and nutrients(Figure 3). Thus a circuit is achieved,which always gives the bacteria thechance to cope with the test com-pound and its intermediates undercompetitive conditions (cf presence ofreadily degradable nutrients). Sincethese tests are run over several monthscorresponding to approximately 100 cycles even very small amounts of recalcitrant metabolites accumulateand are detectable analytically. For alkyl polyglycosides it could be shownthat the biodegradation of this surfac-tant is achieved without residuesbecause the measured removal of the organic carbon does not leaveroom even for the smallest possible

9

Figure 2 Biodegradation of Alkyl Polyglycosides (APG)

Test method

Closed bottle testModified OECD screening test� “readily biodegradable?”

Model sewage treatment plant:Coupled units test

Metabolite test� free from poorly degradablemetabolites?

ECETOC screening test� anaerobically degradable?

C8/16 APG(Plantaren 2000)

73-78–yes

–

–yes*

–yes*

Analyticalparameters

% BOD/CAD% C removal

% C removal

% C removal

% CO2 + CH4

C12/16 APG(Plantaren 1200)

71-7372->80yes

89 ± 2

101.8 ± 2.0yes

98yes

*By analogy

Figure 3 Further Tests on Biodegradation: How Complete is the Degradation?

Formation of poorly degradableintermediates?

Metabolite test

� continuous test with recycling of the effluent and new dosage of substance

� duration of test: up to 3 months

� C concentration in influent andeffluent of test and control plants is measured. C removal [%] is investigated for significant diffe-rence

� (theoretical) formation of an inter-mediate with more than 1 C atommust be excluded (basis of calcu-lation: amount of C atoms of testsubstance)

Problem

Test method

Charac-teristics

Measurementparameters

Evaluation

Degradation also under anaerobic conditions?

ECETOC test /14C digester test

� static test with sludge� duration of test: 4-8 weeks

� measurement of formation of digester gas [% of organic C oftest substance]:- measurement of pressure- 14CO2 + 14CH4

� ≥ 30%: indication of anaerobic(primary) degradation≥ 60%: good anaerobic ultimatebiodegradation

pressure measure-ment apparatus

syntheticwaste-water +test sub-stance

(concentration)

metabolite, a C1 compound (Figure 2).Thus the complete biodegradability of alkyl polyglycosides could be provenexperimentally.

Anaerobic Degradation

The question if surfactants can undergocomplete ultimate biodegradation in the environment has yet another dimension. Surfactants have a marked tendency toadsorb on sludge and sediment par-ticles. Considerable amounts of surfac-tants therefore reach environmentalareas where no oxygen is present forthe biodegradation processes of micro-organisms, e.g. in septic tanks, digesters, sewage treatment plants, sediments ofstrongly polluted aqueous environmentsand, partly, soils. Thus, a comprehen-sive evaluation of the environmental fateof surfactants also has to address theiranaerobic biodegradation behavior (2).In the ECETOC screening test for theassessment of anaerobic degradability,to whose development we have contri-buted and which is now widely applied,the ultimate degradation of a test sub-stance is assessed by measurement ofthe digester gas (carbon dioxide andmethane), see Figure 3. In this screen-ing test, which is regarded as a verystringent degradation procedure, alkylpolyglycosides have shown to be verywell degradable under anaerobic condi-tions (Figure 2). This allows us to con-clude that the representatives of thisnew generation of surfactants are bio-degraded into natural end productsunder all microbial conditions, includingaerobic and anaerobic conditions.Hence, they can be completely reinte-grated into the natural circuit.

Summary

Due to their favourable ecotoxicologicalproperties and their comprehensiveassessment alkyl polyglycosides repre-sent a surfactant group with an excellent environmental compatibility (3). This hasled to the fact that alkyl polyglycosidesas the first surfactant class have beencategorized into a more favorable waterhazard class (WGK 1) by the GermanCommission for the Assessment of Water-endangering Substances (KBwS).

Bibliography(1) Europäische Gemeinschaft; Risk AssessmentDirective 93/67/EEC(2) Steber, J.; Wie vollständig sind Tenside abbaubar? Test- und Auswertemethoden;Textilveredlung 26 (1991) 348-354(3) Andree, H.; Middelhauve, B.; Möglichkeitendes Einsatzes von Alkylpolyglycosiden inWasch- und Spülmitteln; Tenside SurfactantsDeterg. 28 (1991) 413-418

Bernd Fabry

Alkyl Polyglycosides: An Overviewof the Patent Situation

Introduction

Alkyl polyglycosides (APG surfactants) are nonionic surfactants which are based on renewable raw materials. They haveexcellent ecotoxicological propertiesand they are similar to anionic surfac-tants in their foaming and wetting power.

The strong interest of the market in this surfactant class is reflected by the statistics of patent and literaturepublications (Figure 1).

After carefully checking more than 1800patent publications from Henkel andother companies on the alkyl polyglyco-side sector as well as after concludinglicense agreements with Procter &Gamble and Kao Corp., alkyl poly-glycosides should not be assessedmore critically by Henkel customersthan other standard surfactants.

As can be seen, the increase in patentpublications in particular over the pastfive years has been virtually exponential.At present approximately 20 to 30 new articles on APG surfactants are published every month; Henkel alone files 20 to 30 patents a year. If it is already quite diffi-cult for the chemist in the patent depart-ment to cope with this flood of published or already granted patents or patents inthe process of examination, then theproduct developer must be all the more overstretched by this task. Therefore, this article is intended to provide a short sur-vey of the most important interrelation-ships and existing patent positions withemphasis being placed on cosmetics.

1. Mixtures of Alkyl Polyglycosideswith Anionic Surfactants

Among the applicational patents, theEuropean patent EP-B1 0070074 ofProcter & Gamble plays a central role.This patent relates to foaming mixturesof alkyl polyglycosides with surfactantscontaining a sulfate, sulfonate and /or a carboxylate group. It can immediatelybe recognized that this combinationcovers virtually all anionic as well as allamphoteric surfactants with betainestructures. Corresponding patents existfor example in the U.S., Japan andAustralia. The patent may be granted to customers of Henkel on the basis of a contract agreement.

In the course of the opposition pro-ceedings, based on a prior publicationof Rohm & Haas (1), the patent waslimited to mixtures with APG surfac-tants having a chain length of 12 to 18carbon atoms. This means that mix-tures of short-chain alkyl polyglycosideswith for example 8 to 10 carbon atomsand anionic surfactants are largely inthe public domain.

One point which is often discussed inconnection with this key patent is theaverage degree of polymerization (DP)of alkyl polyglycosides, which allowsthe characterization of overlappinghomologue distributions.

With regard to the DP the Procter &Gamble patent contains a lower limit of 1.5, but since this restriction was not necessary for the delimitation fromthe known state-of-the-art, this numeri-cal value must probably be consideredas an approximate value so that mix-tures of anionic surfactants with alkylpolyglycosides types having a lower DP,for example 1.3, are covered.

10

After studying technical chemistry at the TechnicalUniversity of AachenDr. Bernd Fabryreceived his doc-torate on homo-geneous-chemicalhydrogenation pro-cesses. In 1986 heentered Henkel KGaA,Düsseldorf to work for the ResearchDepartment. In thebeginning his workfocused on the development of

anionic surfactants and the analysis of oleo-chemical raw materials. In 1989 he joined thePatent Department and has been responsiblefor oleochemicals and surfactants since 1992.

Patent Situation

Figure 1Development of Patent and LiteraturePublications

250

200

150

100

50

080 82 84 86 88 90 9281 83 85 87 89 91

Year of appearance

Number of publications/patents

Source: Derwent

Although EP-B1 0070074 basically discloses APG /anionic surfactant mix-tures using the example of soaps, alkyl sulfates, alkylether sulfates, alkyl-benzene sulfonates, olefin sulfonates,alkanesulfonates and alkyl betaines, the patent does leave room for selec-tion inventions. Some examples arerepresented in Table 1.

For the manufacturer of cosmetic products the combination of alkyl poly-glycosides with mono- and/or dialkylsulfosuccinates is certainly important; it is the subject of the European patent application EP-A1 0358216 of Kao Corp. A licence on this patent may be obtained by customers of Henkel KGaA withinthe framework of a licence agreement.A synergistic mixture on the basis of alkyl polyglycosides, betaines and protein fatty acid condensates is protected by the European patent EP-B1 0521965 of the Henkel KGaA. An application concerning alkyl poly-glycosides/monoglyceride sulfate compounds is expected to be grantedsoon in the U.S.

The European patent EP-B1 0384983of Hüls AG claims mixtures of APG surfactants with ether carboxylic acids.With regard to the state of the art, the patent had to be limited to unsatu-rated ethercarboxylic acids during theexamination procedure.

Here it must be mentioned that thesepatents are selection inventions, which– if finally granted – are dependentupon EP-B1 0070074. An exception isthe combination of APG surfactantswith alkyl phosphates (EP-A2 0324451,Kao Corp.) since the latter are notcovered by the definition of anionic surfactants chosen in the Procter &Gamble patent.

2. Mixtures of Alkyl Polyglycosideswith Nonionic Surfactants

European patents EP-B1 0075995 andEP-B1 0075996 (Procter & Gamble)claim mixtures of alkyl polyglycosidesand nonionic surfactants. Both patentshave meanwhile been revoked in thefinal instance by the Technical AppealBoard of the European Patent Agency.

However, this does not necessarilymean that mixtures of APG surfactantsare basically free; with regard to thepublication by Rohm & Haas this is at best true for the application of clas-sical nonionic surfactants with short-chain APG surfactants (Table 2).

Kao Corp. for example has filed applications for mixtures of alkyl poly-glycosides with mixtures of nonionicsurfactants with different HLB values as well as with sugar esters.

The subject of WO 93/07249 of Henkel Corp. are synergistic mixtures of short-chain and longer-chain APG types.

3. Mixtures of Alkyl Polyglycosideswith Cationic Surfactants

Mixtures of alkyl polyglycosides withclassical cationic surfactants of the QAV type are to a large extent in thepublic domain. A patent application for combinations of APG surfactantswith esterquats was filed by HenkelKGaA (WO 94/06899).

Cationic polymers are particularlyimportant ingredients for the prepara-tion of hair care and hair treatmentagents. In the European patent EP-B1 0337354, which is currentlyinvolved in opposition proceedings,

Kao Corp. claims mixtures which contain APG surfactants and cationicpolymers. Independent of the furtherfate of this patent, Henkel can grantlicences on this patent to customerswithin the framework of an agreementwith Kao Corp.

4. Mixtures of APG Surfactants with Further Additives

From the large number of applicationsconcerning mixtures of APG surfactantswith further non-surfactant ingredients,let me list just a few examples: combi-nation of alkyl polyglycosides with silicone derivatives (EP-A1 0398177)and /or selected antibacterial agents(EP-A1 0422508) from Kao Corp. aswell as mixtures of long-chain alkylpolyglycosides and the correspondingfatty alcohols as self-emulsifying agents(WO 92/06778, SEPPIC). However, the latter patent (a correspondingFrench patent already exists), seems to be neither new nor inventive. In themeantime, Henkel has raised nullityaction against the French patent.

5. Summary

For the chemist concerned with patentlegislation, the question arises whichlesson to draw from the extremely complex and complicated patent situa-tion. Is there any chance to use alkylpolyglycosides without colliding with a large number of patents in the pro-cess of examination or in the oppositionproceedings or of patents already granted? The answer to this question is – as mentioned above – a clear “yes”if one considers some simple rules:

1. The application of short-chain alkylpolyglycosides for example on thebasis of C8-C10 fatty alcohols is to a

11

Table 2 Claimed Combinations of Alkyl Polyglycosides withNonionic Surfactants

APG surfactants + …

Polyglycol ether mixtures

Sucrose fatty acid esters

Alkyl polyglycosides

Anionic surfactants + amineoxides

Hydroxycarboxylic acid ester

Reference

EP 0408965

EP 0409005

EO 93/07249

EP 0070076

EP 0258814

Patentee

Kao

Kao

Henkel

Procter &Gamble

R.O.L.

Table 1 Claimed Combinations of Alkyl Polyglycosides withAnionic Surfactants

APG + …

Soaps, LAS, FAS, FAES, AOSBetaines

Protein fatty acid condensates+ betaines

Sulfosuccinates

Ethercarboxylic acids

Alkyl(ether)phosphates

Fatty acid isethionates

Acyl lactylate

Reference

EP 0070074

EP 0521965

EP 0358216

EP 0384983

EP 0324451

EP 0075994

EP 0453238

Patentee

Procter &Gamble

Henkel

Kao

Hüls

Kao

Staley

Unilever

large extent in the public domain.This is also true for the combinationof long-chain alkyl polyglycosideswith classical nonionic and cationicsurfactants.

2. Mixtures of C12-C18 alkyl polyglyco-sides with anionics which contain acarboxylate, sulfate and /or sulfonategroup are protected by a Procter &Gamble patent. Accordingly, long-chain APG surfactants cannot beused freely in combinations with themajority of anionic and amphotericsurfactants.

3. Many publications are unexaminedpatent applications which will notprogress beyond this stage. How-ever, they often confuse competitorsand should therefore be thoroughlyevaluated.

Finally, it should be mentioned thatHenkel KGaA concluded a licence agreement with Procter & Gamble Co.in 1993 and with Kao Corp. in 1994.The resulting merger of the most important patent portfolios in the field of APG surfactants (not only in terms of the number of patents), now pro-vides Henkel customers with a broadrange of cosmetic formulation possi-bilities which are sufficiently secure from the viewpoint of patent legislation.Upon request, a detailed description ofthe APG patent situation (2) as well as a list of the patents covered by the Henkel customer license can be provided.The present survey has been compiledto our best knowledge and reflects the status of February 1995. It cannotclaim, however, to be complete nor correct; liability claims are thus excluded. A more precise patent evaluation can only be made in thecase of a concrete formulation.

Bibliography(1) Proserpio, G.; Vianello, G.; Applicazioni tensio-cosmetiche di un nuovo glucoside,Rivista Ital., 56 (1974) 567(2) Fabry, B.; Philipp, M.; Drach, J.; AlkylPolyglycosides – An Overview of the PatentSituation; HAPPI, August (1994) 111

Mathias Rohr and Karlheinz Schrader*

In Vivo Tests: Influence of VariousSurfactants on the Skin

Introduction

Surfactants are the main ingredients inthe formulation of cosmetic cleansingagents. Thus, skin cleansing shouldalways be seen in a direct relationshipwith skin compatibility and other skin-physiological parameters for an optimaldevelopment which require raw mate-rials for mild but still effective cleansing(1, 2). Under the aspect of meetingthese requirements this article dealswith the examination of raw materialsand their effects on human skin fromdifferent points of view.

As an interfacial membrane the stratumcorneum represents a barrier for surfac-tants. Scientists suppose that for mostsurfactants the diffusion resistance ofthe horny layer is 100 times larger thanthat of the living epidermis. Undesiredreactions may occur only after crossingthis barrier, i.e. after damaging the inter-facial layer. In this context the rinse-offbehavior of surfactants from the skinplays an important role for the irritationpotential. Surfactant residues may beadsorbed and penetrate into the result-ing so-called V-spaces of the skinwhere they may trigger undesired reac-tions. Rough skin may especially easilyirritated. Excessive cleansing also leadsto a change in the barrier function. The function of skin as a protectoragainst noxious agents such as soil,lubricating oil and detergents – andthus against further washing applica-tions – is impaired. Other aspectswhich play a role in the evaluation ofsurfactants on skin are: Skin elasticity,sebum content, appearance of skin(erythema, squamation, fissures), sub-jective sensations (itching, tension), pH value, alkali neutralization time andresistance as well as circulation ofblood in the skin (3, 4, 5, 6, 7).

A variety of methods will be presentedto objectify partial aspects of the sur-factant effect on the stratum corneum(8, 9). The general compatibility, accep-tance as well as the damage to the barrier is examined by means of thearm-flex wash test and TEWL measure-ments. The cleansing power is quanti-fied by means of a skin washing

machine; changes in the skin surfacestructure (skin roughness) are examinedby means of laser profilometry (10).

Material and Methods

Table 1 lists the individual surfactantswhich were examined. The tests werecarried out with 1/20 molar solutions.For comparative evaluations, tests inmolar concentrations allow a directcomparison of different surfactantmolecules with different molecularsizes, since equal numbers of surfac-tant molecules are compared. How-ever, this automatically means that the products contain different quanti-ties of washing-active substances (WAS content).

Since only a limited number of productscan be tested on a volunteer collectiveof 20 persons, sodium lauryl sulphate(Texapon K12) in a 2% WAS solution is tested as a further standard product.On the one hand this standard (in thefollowing NaLS-(2% WAS)) allows acomparison reaching beyond the col-lective; on the other hand a test-internalevaluation of the respective test result ispossible through the comparison of themolar content (NaLSmolar) and /or thepercentage (NaLS-2% WAS). TexaponK 1296 and Texapon K 12 are chemicallyidentical; however, they contain differentamounts of active substance.

Arm-Flex Wash Test with TEWL Measurement

The arm-flex wash test with TEWLmeasurement is performed on 20 vol-unteers with healthy skin (11). The product is applied twice a day to thebend of the elbow over 5 days. Duringeach application, one bend of theelbow is foamed with the first test sub-stance and washed with the hand fortwo minutes. After rinsing with warmwater, the product is applied again

12

Dr. Mathias Rohr hasbeen occupying a leading position at theInstitute of AppliedSkin Physiology,Holzminden, Germany.In addition to appliedresearch on problemsin the cosmetics industry his currentfield of activity includesthe development andintroduction of newskin-physiological testmethods. Furthermore,

part of his occupation is the investigation of thelaser profilometry of skin effects of surfactantsolutions and the determination of sun protec-tion factors according to COLIPA. Dr. Rohr isalso a member of the COLIPA Task Force forsun protection factors.

Skin Cleansing and Washing Effects

and washed for another two minutes.After the second warm rinse the area iscarefully dried with a towel (no rubbing).The second bend of the elbow is washed with the second product in the same way. This washing procedureis carried out twice per day of applica-tion, i.e. in total nine times. At the endof the test the volunteers are inter-viewed on the reactions that occurreddirectly after washing.

In a subjective comparison of the testproducts with respect to cleansingeffect and acceptance, the volunteersalso evaluate mildness, improved skinfeel and the overall impression.

Measurement of theTransepidermal Water Loss

The Tewameter (Courage and Khazaka,Cologne) is used for the measurementof water vaporization from surfaces, inparticular from human skin.

For approximately 45 minutes beforethe measurement and during the entiremeasurement procedure, the volunteersstay in a draught-free, air-conditionedtest laboratory at 22˚C and 60% relative humidity. The transepidermalwater loss is measured before theapplication phase of the arm-flex washtest as well as 6 hours after the lastapplication of the test product.

Examination of Cleansing Power

The skin cleansing test according toSchrader is used for the examination ofthe cleansing effects of different sur-factant products. With the aid of a skin

washing machine (Figure 1) a stand-ardized and largely practice-relatedwashing process is carried out and theremoval of a model soil (12) is quantifiedwith the aid of the Minolta chromameterCR 300 in the lab-colour room.

A W/O emulsion is used as a base forthe model soil; the emulsion contains a fat- and a water-soluble dye as wellas a pigment which represents themineral soil. The model soil is com-posed as follows:

4% fat-soluble red dye, e.g. CI 12150; 4% water soluble red dye, e.g. CI 6255; 4% red pigment, e.g. CI 2490; 17%Protegin, INCI: Mineral Oil (and) Petro-latum (and) Ozokerite (and) GlycerylOleate (and) Lanolin Alcohol; 2.5%Tegin O spezial; INCI: Glyceryl Oleate;5.5% Lanolin anhydriquum; INCI: Lano-lin; 6.5% Paraffin oil perliquidum, INCI:Mineral Oil; 10% Vaselin, INCI: Petrola-tum; 46.5% Aqua dest., INCI: Water

The reflection values (L-values) of thecolour measurement are used for theevaluation. The cleansing effect is calculated in percent according to thefollowing formula based on the threeskin colour values (IV = initial value,

AA = colour value after application ofthe model soil and AW = colour valueafter washing):

In order to be able to carry out a stand-ardization beyond the collectives, the cleansing effects (CE) calculatedaccording to the above formula arestandardized in relation to the differencebetween NaLS-2% WAS and Aquadest. so that the standardized cleansingeffect (SCE) can be calculated accord-ing to the following formula:

Laser Profilometry

The quantitative differentiation of sur-factants with regard to their structure-influencing properties of the skin sur-face in the application test is possibleby means of data obtained with a laser scanning system.

In order to detect the influence of thetested surfactants on the surface struc-ture, 20 volunteers are requested tostop using cosmetic agents on thevolar forearm 3 days before the testand for the entire test period. Beforethe first surfactant application, a sili-cone skin-print is taken of each testarea, documenting the initial state.The products are then issued to thevolunteers with the request to applythem to the test areas three times a day over 7 days at intervals of 6 hours.6 hours after the last application skin-prints are taken again. The test pro-ducts are distributed in the areas to bemeasured on a permutational basis inorder to compensate for possible differ-ences in the skin state of the areas.

13

Figure 1 Skin Washing Machine According to Schrader

a) Standardized washing procedure b) Quantification of the model soil

Table 1 Short Overview of the Tested Surfactants with the Respective MolecularWeights, Active Substance Content and pH Values

No.

1

2

3

4

5

Name

Plantaren 2000

Plantaren 1200

Plantaren PS 10

Texapon K 1296(NaLSmolar)

Texapon K 12(NaLS%)

INCI Name

Decyl Polyglucose

Lauryl Polyglucose

Sodium LaurethSulfate + LaurylPolyglucose

Sodium LaurylSulfate (molar)

Sodium LaurylSulfate (%)

Mole-cular mass

375

424

Ø 396

289

289

Active substances%

ca. 53.0

ca. 50.0

ca. 60.0

min. 96.0

min. 90.5

% Content of0.05 molarmass (WAS)

3.538

4.240

3.300

1.505

2.0*

pH Value of0.05 molarsolution

11.1

10.8

9.3

7.1

7.9*

*2% solution

* Dr. Karlheinz Schrader is the owner and generalmanager of the Institute of Applied Skin Physio-logy in Holzminden, Germany. Skin Care Forumrecently published an article by Dr. Schraderentitled “An Evaluation of Sunscreen Prepara-tions”; See Skin Care Forum No.10 (1994).

CEProd. - CEwaterSCE = x 100

CENaLS% - CEwater

AW - AAx 100 = Cleansing effect in

percentIV - AA

The volunteers wash the test areastwice for one minute, allow the productto work in for one minute and then rinse it off.

Similarly to the test described above,an empty segment as well as an areawashed with NaLS-(2% WAS) is testedin addition to the test products to allow a general evaluation of the test collective.

For a non-touch scanning of the skinreplica an automated scanning processwith an optical autofocus sensor (UBMOptical measuring system MicrofocusUBM RC14) is used. The silicone skin-prints are automatically enteredand measured by a robot system of the laser scanning unit controlled by the measuring computer (Figure 2).Upon request, further details may beprovided by the authors.

The changes of the skin profile arequantified by means of various DINparameters Table 2 (14,15,16). A pair-wise Wilcoxon test is carried out tosafeguard the changes found betweenthe points of time “untreated” and “treated” (13). Significances concerningthe change of the end value are calcu-lated as compared to the initial valueand compared to the empty segmentchanges.

Results

Arm-flex Wash TestSome results of the arm-flex wash test are summarized graphically inFigure 3. In each case the evaluationsare summed up where the volunteersmade different evaluations for the testsurfactant and comparative surfactantNaLS-(2% WAS). Figure 3 shows thestandardized sum scores in the form of differences to NaLS-(2% WAS) inorder to allow a comparison of the indi-vidual products beyond the collective.The positive effects are assessed sothat a positive bar represents a better

evaluation. The results of a further arm-flex wash test are described in thearticle by B. Jackwerth in this issue.

TEWL MeasurementFigure 4 summarizes the measure-ment of the transepidermal water lossincluded in the arm-flex wash test inorder to quantify the barrier damagecaused by surfactants. The changes inthe TEWL values are mean values of 20 volunteers. The significance test ofthe results in the pairwise t-test yields a significant change (p < 0.05) for everyproduct. On account of the respectivestandardization of the NaLS-(2% WAS)change to 100% all products can bedirectly compared with each other.

Cleansing EffectsA summary of the results of the wash-ing tests is represented in Table 3. Itshows the initial value (IV), the L-valueafter application of the model soil (AA)as well as the washing value (AW) afterthe washing procedure as a mean valueof 20 volunteers.

The initial value has approximately thesame level for all collectives, so that adirect comparison of the standardizedcleansing effect is possible. Figure 5shows a graphic representation of thestandardized cleansing effect compa-rable to the evaluation of the arm-flexwash test in which the standardized difference as compared to the differ-ence Lauryl sulphate- Aqua dist. isshown. The smaller the negative bar,the smaller is the difference betweenthe standardized cleansing effect andthe NaLS-(2% WAS) solution.

Laser ProfilometryThe DIN parameters Rmax, Ra, RzDINas well as Rk calculated for the respec-tive surfactant products are summarized in Table 4. The individual data revealthat all parameters lie close together,even beyond the different collectives.Consequently, the randomized distribu-tion of the products allows a directcomparison of all products after stand-ardization. Thus, the parameter RzDINin the overall representation of the initialvalues in Table 4 varies around a meanvalue of approx. 152 ± 7 μm, which corresponds to an overall variation(beyond collectives) of approx. ± 5%.

The variations calculated for the nega-tive standard NaLS-(2% WAS) variedfor all collectives between an approxi-mate increase of 2-6%. On average,changes of the empty segment wereapprox. 2%. A significance level of95% of the documented data was notachieved for all products and para-meters, which is due to the relativelylow roughness. From the overall repre-sentation of all parameters and pro-ducts, in particular from the continuouslevel of the negative standard NaLS-(2% WAS) and empty segment beyondthe collectives, a safe evaluation of the data is possible.

14

Figure 2Automated Laser Profilometry withRobot Support

Figure 3Evaluation of the Volunteers as a Sum Score of “Milder, Improved SkinFeel and Overall Better” in the arm-flex wash test as Compared to theNaLS-(2% WAS) Evaluation. NaLS-(2% WAS) = 0.0

norm. sum score (%)

Plantaren2000

Plantaren1200

PlantarenPS 10

NaLS-molar

-50

-25

0

25

50

75

100

125

150

Table 2 Definition of DIN Surface Parameters

Parameter (Lit.)2-dimensional /3-dimensional

Rmax (DIN 4768) /Sp (14)

Ra (DIN 4768) /Sa (14)

RzDIN (DIN 4768-1) /Sz (14)

Rk (DIN 4776)

Meaning

Max. profile height difference;only rough profile characterization

Mean value of the profile data;measure for skin roughness

Mean value from 5 Rmax values;measure for rough structure change

Abbott curve (core roughness);combination of all 3-dimensional measuring datain one parameter

The individual changes in percent afterempty segment correction, in relation tothe change of the negative standardNaLS-(2% WAS) are shown in Figure 6for the products Plantaren 2000,Plantaren 1200, Plantaren PS 10 andNaLSmolar. On account of the stand-ardization chosen, a negative barshows a slightly less pronounced struc-tural change of the skin surface ascompared to NaLS-(2% WAS). Here,Plantaren 1200 and Plantaren 2000 are clearly distinguishable from theother products.

Discussion

Table 3 shows that the standardizedcleansing effect of NaLS-(2% WAS) is90 -93%, beyond the collective limits,as compared to approx. 60% for Aquadist. In the test-internal comparison of NaLSmolar with NaLS-(2% WAS) the standardized cleansing effect of97.95% for NaLSmolar suggests thatthe lower active content leads to areduction of the cleansing effect (17). In the comparison of the three testedsugar surfactants, with 91.7% PlantarenPS 10 shows the highest standardizedcleansing effect PS 10, probably due to the addition of sodium lauryl ethersulfate to the basic formulation. A differ-entiation between different alkyl chainlengths, as e.g. between the productsPlantaren 2000 Plantaren 1200 which was theoretically expected, with respect to the influence on the cleansing effectwas not revealed in this test. Both Plan-taren products have a standardized cleansing effect of approx. 88-89%.This was possibly due to the extremelysticky and covering model soil whichmight cause a leveling of the resultsthrough saturation effects. Therefore,the washing differences to be expectedin theory should be checked in furthertests with a finer model soil.

Within the framework of the laser pro-filometry test Plantaren 1200 shows the smallest negative skin structurechanges as compared to the relativeNaLS-(2% WAS) value. For Plantaren1200 Figure 6 shows a differentiation of 200-250% for the DIN parametersRa, RzDIN and Rk as compared to the negative standard NaLS-(2% WAS).For Plantaren 2000 these three DINparameters also display a positive tendency. However, the differentiationlevel is only approx. 50-75% as com-pared to NaLS-(2% WAS). For Planta-ren PS 10 the laser profilometry datavary around the NaLS-(2% WAS)-level.Especially for Plantaren PS 10, which is no pure sugar surfactant, the mixed

character of the product is expressed in the differentiation as compared toPlantaren 1200 and 2000. Thus, theslightly better cleansing effect of Planta-ren PS 10 in this test correlates withslightly less positive laser profilometrydata. The test-internal comparison of NaLSmolar and NaLS-(2% WAS)supports the tendentially slightly betterDIN parameters Ra, RzDIN and Rk for

NaLSmolar (Figure 6) in relation toNaLS-(2% WAS), the effects assignedto the active content. However, thelaser profilometry data found for theproducts Plantaren PS 10 and NaLS-molar should be understood only astendencies since the differentiation from the NaLS-(2% WAS)-level is notsignificant.

The arm-flex wash test reveals ten-dencies comparable to the objectivelaser profilometry examination. Similarto Figure 6, the positive parameters ofthe arm-flex wash test represented inFigure 3 show a very positive evaluationfor Plantaren 1200. However, in contrastto laser profilometry the other productsare not differentiated in the subjectiveevaluation of the volunteers. In thecomparison, the evaluation of the sugarsurfactants Plantaren 2000 and Plan-taren PS 10 correlate with the laser pro-filometry which is slightly positive forPlantaren 2000 and slightly negative for Plantaren PS 10 (Figure 3).

As shown in Figure 4, the TEWL valuechanges for Plantaren 2000 and Plan-taren 1200 lie in the order of magnitudeof only 15-20% in the relative NaLS-(2% WAS)-measure. Plantaren PS 10,for example, reaches a level of approxi-mately 50%. Comparable to laser profilometry, a clear differentiation ofPlantaren PS 10 and the two otherPlantaren products is revealed in thetest. On account of addition of sodiumlauryl ether sulfate, a clearly higherdamage of the barrier is caused. On theother hand it can also be stated on thebasis of the present data that with astandardized cleansing effect of NaLS-(2% WAS) of more than 90%, theTEWL value increase in the arm-flexwash test is reduced by 50% throughaddition of lauryl polyglucose. For thetest-internal comparison NaLSmolar –NaLS-(2% WAS), similar to the previous

15

Figure 4Change of the TEWL Value During theArm-flex Wash Test in Percent Stand-ardized Against the NaLS-(2% WAS)Field Change

Δ TEWL (%)

Plantaren2000

Plantaren1200

PlantarenPS 10

NaLS-molar

0

30

60

90

15

45

75

Table 3 Skin Washing Test: L-Colour Values of the Different Test Collectives with Respective Cleansing Effect and Standardized Cleansing Effect in Relation tothe Difference Aqua dist. – NaLS-(2% WAS)

Product

Plantaren 2000Plantaren 1200Aqua destNaLS-(2% WAS)

Plantaren PS 10Aqua dist.NaLS-(2% WAS)

NaLSmolarAqua destNaLS-(2% WAS)

Starting value

(IV)

64.5864.6164.4864.86

64.8664.9265.00

64.6964.6764.95

Parameters

Colour value Model soil (AA)

36.6736.3636.2836.50

36.2236.2936.80

35.6835.7635.96

Washing value

(AW)

61.5461.4853.5662.77

61.2352.1662.24

62.4552.4962.92

Cleansingeffect (%)

89.1188.9261.2892.63

87.3355.4390.21

92.2857.8793.00

Standardizedcleansingeffect (%)

88.7688.170.00

100.00

91.700.00

100.00

97.950.00

100.00

Figure 5Comparison of the Standardized Washing Effects in the Washing TestAccording to Schrader Δ (Water-NaLS-(2% WAS)) = 0.0

Δ norm. cleansing effect (%)

Plantaren2000

Plantaren1200

PlantarenPS 10

NaLS-molar

-10

-12,5

-7,5

-5

-2,5

0

2,5

tests for NaLSmolar in relation to NaLS-(2% WAS), the TEWL value increase isslightly reduced, in accordance with the different active contents. In generalthe TEWL measurements also correlatewith the results of the arm-flex washtest and laser profilometry after 6 hoursafter product application. A high TEWLvalue correlates with a bad evaluationof the arm-flex wash test as well as withnegative laser profilometry data.

Summary

The tests reveal that with the aid ofskin-physiological in vivo tests sub-jective evaluation parameters of thearm-flex wash test can be objectifiedand correlated by means of objectivemeasurements, e.g. measurement ofthe TEWL value or of the surfactant-induced skin structure changes bymeans of objectified laser profilometry.

In the case of the observed washingeffects and taking into consideration the possibly covering model soil, all testproducts with molar character showgood to very good washing effects. Of the four surfactants tested within the framework of this test (Plantaren2000, Plantaren 1200, Plantaren PS 10as well as Texapon K 1296) the pro-duct Plantaren 1200 was judged best,followed by Plantaren 2000.

References(1) Schrader, K.; Grundlagen und Rezepturen der Kosmetika; Hüthig Verlag Heidelberg (1979)(2) Raab W.; Kindl, U.; Pflegekosmetik; Govi-Verlag, Frankfurt (1991) 186(3) Braun-Falco, O.; Korting, H.C. (ed.);Hautreinigung mit Syndets; Springer VerlagBerlin (1990) 151(4) Moddé, H.; Schuster, G.: Tronnier, H.;Experimentelle Untersuchungen zum Problemder Hautverträglichkeit anionaktiver Tenside inder Arbeitsmedizin; Tenside 2 (1965) 368-373(5) Frosch, P.J.; Irritancy of soaps and detergentsbars; Chapter 1 in: Frost, P.; Horwitz, S.N. (Eds);Principles of cosmetics for the dermatologist; C. V. Mosby Company, St. Louis Toronto (1982) 5-12(6) Frosch, P.J.; Kligman, A.M.; The soap chamber test. A new method for assessing theirritancy of soaps; J. Am. Acad. Dermatol. 1(1979) 35-41(7) Frosch, P.J.; Tests am Menschen –Testmodelle für Hautirritation am Menschen;Ärztl. Kosmetol. 13 (1983) 397-406(8) Schrader, K.; Rohr, M.; Tenside – Ihre Beurtei-lung hinsichtlich Wirkung und Nebenwirkungen;Euro Cosmetics 1-2 (1994) 18-22(9) Schrader, K.; Meßmethoden zur Prüfung vonKosmetika; SÖFW 118 (1992) 411(10) Rohr, M.; Schrader, K.; Surfactant – inducedSkin Roughness: Quantitative Analysis of theSurface Structure of the Skin Via AutomatedNon-touch Laser Scanning; Euro Cosmetics(1994) 24-28(11) Schrader, K.; Praxisbezogene hautphy-siologische Untersuchungskriterien mit Seifenund Syndets; Parfümerie Kosmetik 71(1990) 686-695(12) Tronnier, H.; Zur Standardisierung vonWaschversuchen an der menschlichen Haut;FSA 67 (1965) 7(13) Hartung, J.; Statistik – Lehr- und Handbuchder angewandten Statistik; R. OldenbourgVerlag München, 9. Auflage (1993)(14) Stout, J.; Sullivan, P.J.; Dong, W.P.; Mainsah,E.; Luo, N.; Mathia, T.; Zahouani, H.; The Development of Methods for theCharacterization of Roughness in ThreeDimensions (1993)

(15) DIN 4768 Ermittlung der RauheitskenngrößenRa, Rz, Rmax mit elektrischen Tastschrittgeräten– Begriffe, Meßbedingungen(16) DIN 4776 Kenngrößen, Rk, Rpk, Rvk, Mr1,Mr2 zur Beschreibung des Materialanteils im Rauheitsprofil – Meßbedingungen undAuswerteverfahren (1990)(17) Schrader, K.; Die hautphysiologischeBewertung von Tensiden; Parfümerie Kosmetik75 (1994) 80-85

16

Table 4 Laser Profilometry: Individual Data of the DIN Parameters Rmax, Ra, RzDIN and Rk with Respective Changes in Percent (delta %) and Changes in Percent After Empty Segment Correction in Percent (delta % - U)

Plantaren 2000NaLS (2% WAS)Leerfeld

Plantaren 1200NaLS (2% WAS)Leerfeld

Plantaren PS 10NaLS (2% WAS)Leerfeld

NaLSmolarNaLS (2% WAS)Leerfeld

A

167.62176.67167.45

166.46171.60150.25

167.02176.56166.85

160.46175.09158.27

E

171.99188.17172.85

166.87173.02156.87

177.07185.18169.80

169.50183.76165.86

Δ%

2.606.513.22

0.240.834.40

6.024.881.77

5.634.954.80

Δ%-U

-0.623.29

-4.16-3.58

4.253.12

0.840.15

A

19.4919.9819.21

19.4219.7416.76

19.1720.2918.49

18.2720.0516.38

E

19.7720.8919.42

18.7220.4216.81

19.6620.8318.74

18.5321.0917.05

Δ%

1.434.581.08

-3.613.420.32

2.562.651.39

1.435.144.11

Δ%-U

0.353.50

-3.933.10

1.171.26

-2.681.04

A

154.34159.24153.13

153.19153.71137.18

150.85159.93149.51

147.22157.57140.78

E

155.52164.25155.70

149.15156.54139.73

158.87166.44149.79

149.56161.76144.31

Δ%

0.763.141.68

-2.641.841.86

5.314.070.19

1.592.662.51

Δ%-U

-0.921.46

-4.50-0.02

5.123.88

-0.920.15

A

23.9925.1023.09

23.7324.2120.81

23.9123.3124.65

22.7825.0020.98

E

24.6126.3523.77

23.0324.7120.66

24.9724.8424.83

23.6026.3520.76

Δ%

2.614.982.96

-2.922.06

-0.70

4.426.580.72

3.605.42

-1.05

Δ% -U

-0.352.02

-2.212.76

3.715.87

4.656.47

Produkt Rmax/ [μm] Rx/ [μm] RzDIN/ [μm] Rk / [μm]

Figure 6Laser Profilometry: Change of the DIN Parameters Ra, RzDIN and Rk inPercent Standardized After EmptySegment Correction on the Differenceof the NaLS-(2% WAS) Test Area

Ra: mean roughness according to DIN4768 (15); RzDIN: average roughnessaccording to DIN 4768/1; Rk: Core rough-ness – depth of the surface profile withexclusion of profile peaks and ridges (16)

Δ Ra /Δ RzDIN /Rk (%)

Plantaren2000

Plantaren1200

PlantarenPS 10

NaLS-molar

02550

-25-50-75

-100-125-150-175-200-225-250

RaRzDINRk

(page 1 continued)By variation of the chain length of thefatty alcohol and the number of glucosegroups the structures of the propertiesof the APGs may be influenced. As aspecialist in this field, Henkel providesan APG product range for a widevariety of applications.

Publisher: Henkel KGaA, Ressort Oleochemie, COSPHA, D-40191 Düsseldorf, GermanyEditors: K. Raabe, S. Einemann, Dr. S. WallatFrance: Jean-François Herbé, Tel. (1) 60.65.21.00; Fax (1) 60.65.21.01; Sidobre-Sinnova S.A., St-Fargeau-PonthierryGreat Britain: Mark Leonard, Tel. 081-311-4149; Fax 081-310-0620; Henkel LimitedSpain: Esther Prat, Tel. (34) 32904850; Fax (34) 32904878; Pulcra S.A., BarcelonaUSA: Patricia Mayer, Tel. (215) 628-1476; Fax (215) 628-1450; Henkel Corp., Ambler, PennsylvaniaJapan: Katsumi Sasaki, Tel. 81-3-3664-2558; Fax 81-3-3664-2559; Henkel Hakusui Corp.,TokioCorrespondence: Skin Care Forum, c/o Hen kel KGaA, CFC PM Wissenschaftlicher Service, Z 20; D-40191 Düsseldorf; Germany Tel. (0211) 797 2443, Fax (0211) 798 7696Translations: TTP Sprachendienst, H. Kähler, S. EinemannRealization: CPC Werbung/Advertising, H.- J. Tasch, Y. KüppersDesign: Böhm & Kleinhans GmbH, D-40859 Ratingen, GermanyLitography: Rheinische Reprotechnik GmbH, D-40231 Düsseldorf, GermanyPrinted by: Druck und Verlagsgesellschaft mbH D-40008 Düsseldorf, GermanyAll contributions and original articles published in theSkin Care Forum may only be reproduced with specialpermission and provided that the source is acknow-ledged. The Skin Care Forum accepts no responsibilityfor any opinion expressed or statements made in contributions or reproductions from other sources.