Blister & Strip Packaging

Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management,SVKM’S NMIMS, Mumbai

Dr. Anil M. Pethe

Blister Pack Introduction Blister pack is a term for several types of

pre-formed plastic packaging used for small consumer goods.

The two primary components of a blister pack are the cavity or pocket made from a "formable" web, either plastic or aluminum the lidding, made from paper, paperboard,

plastic or aluminum. The "formed" cavity or pocket contains

the product and the "lidding" seals the product in the package.

Blister Pack Introduction (Cont.) Blister packs are commonly used as unit-dose packaging for

pharmaceutical tablets, capsules or lozenges. Blister packs can provide barrier protection for shelf life

requirements, and a degree of tamper resistance. In the USA, blister packs are mainly used for packing physician

samples of drug products, or for Over The Counter (OTC) products in the pharmacy.

In other parts of the world, blister packs are the main packaging type since pharmacy dispensing and re-packaging are not common.

A series of blister cavities is sometimes called a blister card or blister strip as well as blister pack. In some parts of the world the blister pack is known as a Push-Through-Pack (PTP).

Blister Pack Introduction (Cont.) The main advantages of unit-dose blister packs over other

methods of packing pharmaceutical products are the assurance of product/packaging integrity (including shelf life) of each individual dose

The possibility to create a compliance pack or calendar pack by printing the days of the week above each dose.

Blister packs also hinder the use of OTC drugs in the manufacture of illegal drugs.

Consumer goods Blister Packs Other types of blister packs consist of carded packaging where

goods such as toys, hardware, and electrical items are contained between a specially made paperboard card and clear pre-formed plastic such as PVC.

The consumer can easily examine the product through the transparent plastic.

The adhesive is strong enough so that the pack may hang on a peg, but weak enough so that the package can be easily opened.

Consumer goods Blister Packs (Cont.) Sometimes, with large items, the card has a

perforated window for access. A more secure package is known as a

clamshell. It is often used to deter package pilferage for

small high-value items, such as consumer electronics.

It consists of either two pre-formed plastic sheets or one sheet folded over onto itself and fused at the edges. They are usually designed to be difficult to open by hand so as to deter tampering.

A pair of scissors or a sharp knife is often required to open them (although often coming in the same package).

They provide barrier protection for shelf life requirements. They also provide a degree of tamper resistance. The most important reason for introducing blister packaging

technology was to offer patients a clearly marked individual dose, enabling them to check whether they had taken the prescribed drugs on a given day.

Moreover, the drugs that were not taken remained in the original package and were fully protected against adverse external conditions.

The patient could handle the blister package more easily and could store it more conveniently than conventional packages.

Protection from Moisture, Gas, Light & Temperature Compliance – Regulatory & Patient

Uses of Blister Packaging

Advantages of blister packaging Reduced costs and higher packaging speeds relative to

other packaging materials. Blister packaging helps retain product integrity because

drugs that are prepackaged in blisters are shielded from adverse conditions.

Furthermore, opportunities for product contamination are minimal.

and each dose is identified by product name, lot number, and expiration date.

Advantages of blister packaging (cont.) Blister packaging protects pharmaceuticals in the home

better than bottles do. Tamper evidence is another strength of blister packaging.

The dosage units are individually sealed in constructions of plastic, foil, and/or paper. With blister packaging, however, each tablet or capsule is individually protected from tampering until use, so any form of tampering with a blister package is immediately visible.

Basic configuration of blister packagingTwo basic types of pharmaceutical blister packages exist;1. In one variety the cavity is constructed of clear, thermoformed

plastic, and the lid is formed of clear plastic or a combination of plastic, paper, and/or foil.

2. The other type of package contains foil as an essential component of both webs, and its cavity is created by cold stretching.

Production of BlistersThere are 3 different methods for production of blisters

Thermoforming

Cold forming

Thermo-cold complex blistering

Production of Blisters

Thermoforming In the case of thermoforming, a plastic film or sheet is unwound

from the reel and guided though a pre-heating station on the blister line.

The temperature of the pre-heating plates (upper and lower plates) is such that the plastic will soften and become pliable.

The warm plastic will then arrive in a forming station where a large pressure (4 to 8 bar) will form the blister cavity into a negative mold.

The mold is cooled such that the plastic becomes rigid again and maintains its shape when removed from the mold.

In case of difficult shapes, the warm film will be physically pushed down partially into the cavity by a "plug-assist" feature.

Plug-assist results in a blister cavity with more uniform wall distribution and is typically used when the cavity size and shape is larger than a small tablet.

Cold forming In the case of cold forming, an aluminum-based laminate film is

simply pressed into a mold by means of a stamp. The aluminum will be elongated and maintain the formed shape. In the industry these blisters are called cold form foil (CFF)

blisters. Advantage of cold form foil blisters is Use of aluminum offers a near complete barrier for water and

oxygen, allowing an extended product expiry date. Disadvantages of cold form foil blisters are: The slower speed of production compared to thermoforming The lack of transparency of the package The larger size of the blister card (aluminum can not be formed

with near 90 degree angles).

Components of blisters The four basic components of pharmaceutical blister packages are;

1. The forming film (Forming films account for approximately 80–85% of the blister package)

2. The lidding material (lidding materials make up 15–20% of the total weight of the package.)

3. Heat seal coating 4. Printing ink

1. Forming Film The forming film is the packaging component that

receives the product in deep drawn pockets. One key to package success is selecting the right

plastic film for the blisters in terms of its; Property type, Grade, Thickness.

Selection of forming filmConsideration must be given to the;

Height and weight of the product, Sharp or pointed edges of the final package, The impact resistance, Aging, migration, and cost of the film. The plastic also must be compatible with the product. Factors influencing package production and speed of

assembly must be taken into account, including heat sealing properties and the ease of cutting and trimming formed blisters.

Types of forming film Thermoforming film

PVC (Poly vinyl chloride) PCTFE (PVC/Polychlorotrifluoroethylene) PVDC (Polyvinylidene chloride) PS (Polystyrene ) Cyclic olefin copolymers (COC)

Cold forming film Aluminum foil

Polyvinyl Chloride (PVC) The most basic material for the forming web is PVC or Polyvinyl

Chloride. The principal advantages of PVC are the low cost and the ease of

thermoforming. The main disadvantages are the poor barrier against moisture

ingress and oxygen ingress; moreover PVC has a negative environmental connotation due to its chlorine content.

In the case of blister packaging the PVC sheet does not contain any plasticizer and is sometimes referred to as Rigid PVC or RPVC.

In the absence of plasticizers, PVC blisters offer structural rigidity and physical protection for the pharmaceutical dosage form.

On the other hand, the blister cavity must remain accessible by the push-through effect and the formed web may not be too hard to collapse when pressed upon;

Polyvinyl Chloride (PVC) For this reason the PVC sheet thickness is typically chosen

between 200µ to 300µ depending on the cavity size and shape. Most PVC sheets for pharmaceutical blisters are 250µ or

0.250 mm in thickness. Typical values for the WVTR or MVTR of a 250µ PVC film are

around 3.0 g/m2/day measured at 38°C/90%RH The Oxygen Transmission Rate (OTR) is around 20 cc/m2/day. In order to overcome the lack of barrier properties of PVC film, it

can be coated with PVDC or laminated to PCTFE or COC to increase the protective properties.

Multi-layer blister films based on PVC are often used for pharmaceutical blister packaging, whereby the PVC serves as the thermo formable backbone of the structure.

Also, the PVC layer can be colored with pigments and/or UV filters.

Barrier Packaging foils Low barrier film – PVC

Medium barrier film – PVDC

High barrier film – ACLAR (PCTFE) & ALU/ALU

Poly-chloro-tri-fluroethylene (PCTFE) Polychlorotrifluoro ethylene or PCTFE can be laminated to PVC

to obtain very high moisture barrier. Typical constructions used for pharmaceutical products are 250µ

PVC film laminated to 15µ-100µ PCTFE film. Duplex structures are PVC/PCTFE Triplex laminates are PVC/PE/PCTFE. Deeper cavities can be formed by using the triplex structures

with PE. Typical WVTR values are between 0.06 - 0.40 g/m2/day.

Polyvinylidene Chloride (PVDC) PVC/PVdC laminations PVC is coated with an emulsion of PVdC (Polyvinylidene Chloride) The coating weights of PVdC commonly used are 40, 60, 90, g per

m², and the film is offered with or without a middle layer of polyethylene.

The polyethylene is used with heavier coating weights such as 60 and 90 g per m², to improve the thermoforming characteristics of the blister cavity.

Cyclic olefin copolymers (COC) Cyclic olefin copolymers (COC) or polymers (COP) can provide

moisture barrier to blister packs, typically in multilayered combinations with polypropylene (PP), polyethylene (PE), or glycol-modified polyethylene terephthalate (PETg).

Cyclic olefin resins are generally amorphous and are noted for good thermoforming characteristics even in deep cavities, leading some to use COC in blister packaging as a thermoforming enhancer, particularly in combination with PP or PE.

Films can be manufactured via coextrusion or lamination. WVTR values of commercial cyclic olefin-based pharmaceutical blister

films typically range from 0.20 to 0.35 g/m2/day at 38C/90% RH. Unlike PVC and other common pharmaceutical barrier resins, cyclic

olefin resins do not contain chlorine or other halogens in their molecular structure, being comprised solely of carbon and hydrogen.

Cold form foil is used for products that are extremely hygroscopic or

light sensitive. It is an extreme moisture barrier and consists of three

layer: PVC, aluminium foil and nylon.

Comparison of forming film

mil- a unit of length equal to 1⁄1000 inch used especially in measuring thickness (as of plastic films)

2. Lidding MaterialThe lidding material provides the base or main structural component upon which the final blister package is built.

It must be selected according to;The size,Shape,Weight of the product As well as the style of the package to be produced

Consideration in selection of lidding material

The surface of the lidding material must be compatible with the heat-seal coating process.

Clay coatings are added to the lidding material to enhance printing.

Heat-sealing and printability are both important considerations in blister packaging, and the lidding material must offer the best workable compromise.

Aluminum Primary component of lid stock is aluminum and its gauges

varies from 18-25 µm (0.0078 to 0.001 inch). Side of aluminum foil laminate in contact with the product

provides the heat sealable layer that forms the seal to the blister material.

Different designs of lid stocks are available and selection of a particular design depends on how the packages will be used.

Standard designs includes Peelable , Push-through and Child-resistant

Peelable foil Peelable foil can be peeled away from the blister. With the peelable foil lid stock, which is used in

conjunction with blister tooling, a three step process is required to open the blister.

Child resistant foil For child-resistant peelable foil, a layer of polyester with the

appropriate adhesives would be added. This type will gives more protection for the kids against

deliberate consumption of medicines. The blister cavity must be separated from the rest of the blister card. The paper and the polyester layers are pulled back from an

unsealed area. The product is pushed through the remaining aluminum foil.

Push-through foil Two commonly used types of Push-through foil are-one with a

paper outer layer separated from the aluminum by a layer of adhesive and one without paper.

The paper outer layer serves as an aesthetic and makes it possible to print on the back of the blister.

Comparison of lidding material

3. Heat seal coating Heat-seal coatings provide a bond between the plastic blister

and the printed lidding material. For blister packages, heat-seal coatings are perhaps the most

critical component in the entire system. The appearance and physical integrity of the package depends

upon the quality of the heat-seal coating. These solvents or water based coatings can be applied to rolls

or sheets of printed paperboards using roll coater or flexographic methods, knives, silk screenings or sprays.

Whatever the system, it is essential that the proper coating weight be applied to the lidding material for optimum heat sealing results.

A successful heat-seal coating for blister packages must exhibit;

Good gloss, Clarity, Abrasion resistance, hot tack must seal to various blister films.

Heat seal coating (cont.)

Hot tack Hot tack is particularly important because the product usually is

loaded into the blister and the lidding material heat sealed in place (face down) onto the blister.

When the package is ejected from the heat-seal jig, the still-warm bond line must support its entire weight.

The heat seal coating must precisely match the lidding material and the plastic material of the forming film.

Precisely match means that with pre determined sealing parameters, a permanent sealing effect between the lidding material and the forming film must be guaranteed under any climatic condition.

4. Printing Inks Printing inks provide graphics and aesthetic appeal. They can be applied to the lidding material by letterpress,

gravure, offset, flexographic, or silk-screen printing processes Printing inks must

Resist heat sealing temperatures as high as 300 C without showing any discoloration or tackiness.

Sufficiently resist abrasion, bending, and fading. Be safe for use with the intended product. Comply with FDA recommendations.

Blister Packaging machine

1. Thermoform blistering machine2. Cold form blistering machine3. Thermo-cold complex blistering machine

Production of Blisters

Thermoforming In the case of thermoforming, a plastic film or sheet is unwound

from the reel and guided though a pre-heating station on the blister line.

The temperature of the pre-heating plates (upper and lower plates) is such that the plastic will soften and become pliable.

The warm plastic will then arrive in a forming station where a large pressure (4 to 8 bar) will form the blister cavity into a negative mold.

The mold is cooled such that the plastic becomes rigid again and maintains its shape when removed from the mold.

In case of difficult shapes, the warm film will be physically pushed down partially into the cavity by a "plug-assist" feature. Plug-assist results in a blister cavity with more uniform wall distribution and is typically used when the cavity size and shape is larger than a small tablet.

Advantages of thermoforming blister pack:The most basic material for the forming web is PVC or Polyvinyl Chloride, for ease of thermoforming and low cost.The product can be visually examined through the transparent plastic. The faulty blister card can be rejected via the inspecting camera or naked eyes.Because the cavity or pocket contain the item snugly, it can adopt the universal feeder which consists of circular brushes and planetary agitators that sweep the products into blister pockets. Parts are not required for different formats. This feeder is noted for its low cost and ease of operation.

Disadvantages of thermoforming blister pack:The protective properties are not strong because of the PVC’s poor barrier against moisture and oxygen ingress.Not suitable for light-sensitive drugs because of the transparency of PVC.

ThermoformingThermoforming process consists of four basic stations where following

operations occur1. Forming

• Pre heating• Thermoforming• Cooling

2. Filling (Loading)3. Sealing4. Finishing

Schematic Representation of Thermoforming

Pre-heating Heating station is present only in thermoform & thermo-cold

form blistering machines. Prior to entering forming station, reel-fed base (tray) web

(blister material) passes through the heating unit. Heating is achieved either by

Infra-red heaters Contact heaters

The temperature , based on the blister material used and on the speed at which that material travels through the heating station , is a critical parameter for optimal performance .

Forming At the forming station the blister material is heated to the

point where the plastic softens sufficiently to allow the cavity to be formed by Mechanical forming between male and female moulds Vacuum or negative pressure-which draws the softened film over or

into a mould

Forming (Cont.) Pressure-in which compressed air forces the film over or into

a mould Combination of the two

For an identical blister shape, pressure plus plug assistance generally gives most uniform blister.

Cooling

The moulds into which the plastics is formed can be cooled by air, water or chilled water

The cooling station cools the films after the forming process. (Laminates containing aluminum do not need to be cooled.)

Filling (Loading) Here product is loaded into blister cavity either manually or

with the aid of feeding mechanism Uncoated tablets or capsules are normally fed from vibratory

bowl via channels or tubes by gravity. Vacuum extraction is frequently applied to the bowl tubes etc

to minimize powder and tablet chips which may finish up in the seal or tray.

The critical parameter is the proper filling of formed blisters

Sealing At this station, lid stock is sealed to filled blister cavity, using

heat and pressure. The critical parameters to be considered at this station are

temperature, pressure . The lid stock material is staged on a roll above the blister cavity

and may be preprinted or printed on line. Lot no. and expiration dates may be applied at this point. Preprinted lid stock materials will require a print registration

system to control the position of the printing relative to the blister cavity.

The critical parameters at this part of station includes legible and correct labeling.

Finishing Includes embossing, perforation and cutting. Embossing involves application of lot no. and expiration date to

package. This process is carried out at printing station. Steel type is used to emboss information on the edges of the

blister package. At Trimming station, the blisters are cut into individual unit Embossing, perforation, cutting process should not

compromise blister lid or seal. Package integrity and quality of embossing are critical parameter in the process.

Cold forming In the case of cold forming, an aluminum-based laminate film is

simply pressed into a mold by means of a stamp.

The aluminum will be elongated and maintain the formed shape.

In the industry these blisters are called cold form foil (CFF)

blisters.

Advantage of cold form foil blisters is Use of aluminum offers a near complete barrier for water and oxygen, allowing an

extended product expiry date.

Disadvantages of cold form foil blisters : The slower speed of production compared to thermoforming; The package is opaque, making the inspecting system, which rejects the faulty blister card, complicated and costly. The cost of cold forming aluminium film is higher than PVC.The larger size of the blister card (aluminium cannot be formed with near 90 degree angles) increases the material cost.Because the cavity or pocket is larger than the drug, the feeder should be dedicated. this increases the cost and difficulty of operation.

Operation of Cold FormingThe sequence involves;Installing the Aluminium Foil, Cold forming it into blister cavities via punch pins, Loading the blister with the product, Placing lidding material over the blister, Heat-sealing the package. Cutting into individual blisters

Types of Cold forming processes1. Clamping the material and carrying out a true punch action

where the non-held area is extended (stretch forming).2. Taking a foil which has been embossed or finely creased; can be

extended by air or mechanical pressure without showing flex cracks.

3. Taking a reel of material with regular cross-direction slits (as used on suppository machine).

4. A male/female mechanical forming operation is carried out between each slit. This mechanical operation forms the foil and the slit area moves (opens), thereby preventing any high degree of stress

5. Latest innovations include a double forming operation which reduces the tray size to 20% (Advanced Forming Technology (AFT) process). These tend to use Teflon stretching dies.

Larger size of the cold forming blister pack compared to thermoforming blister pack.

Thermo-cold formingExample: ALU-Tropical MachineOperation:The sequence involves; Heating the plastic, Thermoforming it into blister cavities, Loading the blister with the product, Placing lidding material over the blister, And heat-sealing the package. Installing the aluminium foil Cold forming it into blister Pouch & seal it on

thermoformed blister to give extra protection, Cutting into individual blisters

Strip Packaging

Strip packs present an alternative form of pack for a unit dosage.

Strips can be produced from single or multi-ply materials, provided the two inner plies can be sealed by heat or pressure (e.g. cold ‘self-adhesive’ seal).

Materials can range from relatively permeable plies to those which incorporate a foil ply of sufficient thickness (and effectiveness of seal) that an individual hermetic seal is produced for each dosage.

Usually produced at lower speeds and also occupy greater volume than blisters.

59

Strip Packs

Consists of one or two plies, made from Regenerated cellulose Paper Plastics, Foil or any combination --------------an item is inserted into a pocket area against

a recess in a heated roller

Strip Packs (cont.)

Heat Sealable Cellophane Heat Sealable Polyester Paper / Polyethylene / Foil

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Strip forming material

Strip packaging offers a more user-friendly packaging solution than bottled tablets and capsules.

It provides economical packaging solutions for highly sensitive drugs.

It is a strong and perfect pharma packaging material for protection and distribution of the drug.

Strip packaging is the exact size of the capsule or the tablet in question. It keeps the pills and capsules organized, separated and safe.

Strip packaging allows one to consume a single tablet without touching the packaging of the other tablets.

Advantages of Strip Packaging

Basically a strip pack can be formed by introducing an item which extends a pocket area during insertion or by a preforming operation prior to filling.

As the latter method gives less strain (or more controlled forming) to the pocket area and reduces the material needed by 20–35%,

Either one or both sides of the plies may be mechanically formed, but this process can only be applied to materials which will ‘stretch’ without tearing.

Strip packaging machines are far simpler and smaller than blister packaging units, usually simply consisting of a feed system, product insertion plus heat sealing, and a guillotining operation to size.

Feed is usually via a vibratory bowl with feeding tracks (usually up to a maximum of sixteen).

Alternatives are a rotating table plus drop or sweep.

Most machines employ a vertical feed (gravity drop) but occasionally the web is run horizontally with a platen type sweep.

The pocket area is created by recesses either in a platen or more usually in a heat sealing cylinder, where a circumferential point seal is made between two intermeshing cylinders.

As with blister packs, the maximum speed depends on the size of the item and gravity. A maximum speed of 250–300 per track is likely with a 325 mg (five grain) type of aspirin product.

Removal of powder, chips, etc. is achieved by vacuum extraction. Cutting of the emerging web is invariably done by either a scissors

or guillotine motion or rotary die cutting. Additional stages which can be incorporated into the machine

include printing, perforating, batch coding, etc.

As distinct from blisters, perforation does not usually add to the seal width, as pocket seals are nominally 5 mm or more.

Most machines use two separate webs but occasionally a single centrally folded web may be employed.

Strip packaging is closely allied to sachet packing and in certain cases it is difficult to differentiate between the two.

Two different plies can also be used (top and bottom) provided the sealants are compatible.

Strip designs Strip designs are very basic, as the emerging units are

invariably rectangular or square strips. The pocket portion can, however, be round, oval or square. The pocket area is critical to the diameter, shape and thickness

of the product. If the pocket is too ‘tight’, tearing, perforation of the pocket

periphery or wrinkling of the seal area may occur. The seal width may be as low as 4 mm, but usually 5 mm and

above is employed. If the seal area is likely to wrinkle or crease then wider seals may be necessary.

Materials of Construction/ Type

Critical Properties Area of use

PVC 200/250/350 Low barrier / Simple unitpack / Aesthetic

Stable products like Paracetamol,Co-trimoxazole, certain softgel capsules etc.,

PVC / PVdC (250/40) Low barrier better than PVC Products not very sensitive to moisture, gasesand with moderate self life- Multivitamin tabletsand capsules

PVC / PVdC (250/60)/ (250/90)/ (250/120)

Good barrier Moderate to high sensitive range of products,certain FDC/ Enzyme products

PVC / PE / PVdC (200/25/60)/(250/25/90)(300/30/90)

Good barrier Quite high sensitive range of products – 4FDC(RHZE)

Ultrasafe Duplex High barrier/economical Quite high sensitive range of products

Ultrasafe Triplex High barrier/economical Quite high sensitive range of products

PVC/Aclar (PCTFE) (10μ to 100μ)

Excellent barrier Extremely sensitive range of products

PVC/COC, PE/COC Excellent barrier Extremely sensitive range of products

OPA/Al foil/PVC Excellent barrier Extremely sensitive range of products

Materials of Construction/ Type Critical Properties Area of useAlu/Alu Excellent barrier Extremely sensitive range of products

OPA/Al foil/PVC(OPA- Oriented polyamide)

Excellent barrier Cefuroxime Axetil tablets, Levocetirizine Tablets,

Alu/Alu with desiccant Excellent barrier Extremely moisture sensitive range of products

Aluminium foil with HSL (Hard tempered) 0.02 / 0.025

Excellent barrier Lidding foil for blister packing

Aluminium foil(Hard tempered with special coating)

Excellent barrier Lidding foil for COC

Aluminium foil / poly (30 –40 microns (soft tempered)

Excellent barrier For strip packing use of very sensitive range ofproducts – Omeprazole Capsules, RanitidineTablets etc.,

Aluminium foil / VMCH (30 –40 microns (soft tempered)(VMCH- Vinyl Acetate - Maleic Acid - Vinyl Chloride Copolymer)

Excellent barrier For strip packing use of dark colored sugarcoated tablets.

Paper /Poly Very low barrier / Simple unitpack / Aesthetic look

Very economical pack for very stable products.

Paper/ AL/HSL (heat seal laquer) Excellent barrier For Child resistance blisters pack

Choosing suitable polymer/blister packsComparative WVTR values of various blister films on flat sheet (38 deg C/90% RH - g/m2/day)

Materials of Construction / Type

WVTR values (g/m2/day)

PVC 250 03Polypropylene 01PVC / PVdC (250/40) 0.75PVC / PVdC (250/60) 0.5PVC/10μ PCTFE (Aclar) 0.45COC 190 μ 0.35PVC/15μ PCTFE (Aclar) 0.36PVC / PE / PVdC (250/25/90) 0.31PVC/20μ PCTFE (Aclar) 0.27COC 240 μ 0.28COC 300 μ 0.23PVC/23μ PCTFE (Aclar) 0.23COC 350 μ 0.2PVC/38μ PCTFE (Aclar) 0.15PVC/51μ PCTFE (Aclar) 0.11PVC/75μ PCTFE (Aclar) 0.08PVC/102μ PCTFE (Aclar) 0.05CFF (Alu/Alu) PVC/Alu45/OPA25 0

Representative Cost Comparison for Packages Containing 30 tablets

Packaging Material Material Cost ($)

Labor Cost ($) Total Costs ($)

Glass bottle 0.51 0.70 1.21

Plastic bottle 0.125 0.70 0.825

Blister Pack 0.07 0.25 0.32

Reference: Pharmaceutical Technology, November 2000

ALU-ALU PackagingALU-ALU Packaging

ALU ALU Blisters

Introduction

Alu Alu Foil is an excellent multilayered structure designed for high sensitive range of Pharmaceutical and generic medicines which are highly hygroscopic or light sensitive and cannot be suitably packed with barrier plastic films.

The structure is an optimized combination of aluminium foil and polymeric films with the alumina layer sandwiched between an inner heat sealable polymeric film and outer supportive malleable film.

Introduction (cont) Alu-alu blister represents the new generation in

pharmaceutical packaging, its the material with best barrier performance at present, and can absolute resist vapor, oxygen and UV rays, good performance of aroma barrier.

Each blister is a single protection unit, no effect to barrier after opening first cavity, especially suitable for drugs that easy to be affected in wet regions and tropics.

Alu-alu blister can be shaped in various appearances by changing mold, simultaneous, its glorious silvery white luster no doubt can promote selling.

Aluminium Foil for Pharmaceutical Packaging (BIS Specification)

Bare Blister Pack Foil Bare foil (of thickness 20-25 µ without any lamination or coating)

used for blister pack application for pharmaceutical packaging usually after coating.

Coated Blister Pack Foil Bare foil (of thickness 0.20-25 µ) with one side coated with heat

seal lacquer and the other side with primer or printed, used for blister pack application in pharmaceutical packaging.

Bare Pharma Strip Pack Foil Bare foil (of thickness 30-40 µ without any lamination or coating)

used for strip pack application for pharmaceutical packaging.

Benefits of ALU ALU Packaging 100% Barrier against water vapour, gases, light etc Excellent Thermo-formability High degree of Thermal stability High Malleability for deep drawing blister cavities Effective anti counterfeit packaging

Cold forming for ALU ALU In the case of cold forming, an aluminum-based laminate film is

simply pressed into a mold by means of a stamp. The aluminum will be elongated and maintain the formed shape. In

the industry these blisters are called cold form foil (CFF) blisters. Advantage of cold form foil blisters is

Use of aluminum offers a near complete barrier for water and oxygen, allowing an extended product expiry date.

Disadvantages of cold form foil blisters are: the slower speed of production compared to thermoforming the lack of transparency of the package The larger size of the blister card (aluminum can not be formed with near 90

degree angles).

Manufacturing of ALU ALU Blister

Evaluation of Blister/Strip1. WVTR Studies A desiccant (usually silica gel or magnesium chloride) is placed

inside the blister rather than the actual pharmaceutical product. This standard was introduced decades ago by U.S. Pharmacopeia. These blisters to be placed in an environmental chamber at

constant temperature and humidity conditions (there are several combinations, but the most common one is 23°C and 75%RH).

The weight of the sample blister is then measured at certain intervals of time for 28 days.

From the weight gained and the number of individual blisters in the pack, the Water Vapor Transfer Rate (WVTR) is determined in terms of grams of water per day per blister.

A typical blister pack with two cavities and silica gel desiccant is shown in above Figure

1. WVTR Studies (cont.) By today’s standards, this traditional U.S.P. method is time

consuming and prone to errors. Therefore, several companies are improving the effectiveness of

their testing by using Gravimetric Sorption Analyzers to measure the rate of water permeation.

The improved procedure consists of hanging several blisters filled with desiccant inside sample cavity and monitoring its weight under selected temperature and humidity using precision microbalance design.

Typically, this testing is done at 25°C at 60%RH, 30°C at 65%RH and 40°C at 75%RH and the experiment is run until steady state conditions are reached in each case.

An experiment might last from 3 to 5 days depending on the permeation properties of the particular blister material.

This testing protocol is based on the methods issued by the (ICH).

2. Vacuum tests Immerse the test package in a container containing colored

water (15–25°C) and place the container in the vacuum chamber.

Apply the appropriate vacuum of 33 kPa (250 mm of mercury) for strip packages or 24 kPa (180 mm of mercury) for blister packages, for 30 s.

Restore atmospheric pressure and remove the container from the vacuum chamber.

Remove the test package from the container and blot off the excess water. Examine the package for ingress of water into the pockets.

Blister / Strip Defects Common defects includePin-hole Seal defectCurls of traysSharp edgesblocking

Pin Holes Foil of 0.03 mm is pin hole free Foil of 0.0177 mm can be consider commercially free for

most purposes. 0.009 mm foil may contain 100-700 pin holes/m2. Permeation through pin holes can be reduced by lamination.

Seal DefectsSeal defects occurs due toImproper alignment of foil & film during sealing.Excess heatingQuality of material

Curl Of Trays Occurs due to heat-sealing operation Amount of curl depends partially on type of

machine employed, the type of web and design of tray.

Curl occurs due to different co-efficient of expansion for foil and film plus film shrinkage due to molecular reorientation.

REMEDY: By incorporating thermoformed ribs in the

tray Reversing the web curvature by passing over

a tension roller .

Sharp Corners & Blocking

SHARP CORNERSIt occurs during punching out or die cuttingIf not handled carefully may penetrate pockets of trays.

BLOCKING: During manufacturing two adjacent layer of film stick together

Damaged Tablets

In Blister packing the dimensions of the tablets plays a very important role.

It invariably gets jammed in the transport chutes thus producing unfilled / half filled / broken tablets in to blisters.

This dimensional check improves the efficiency of the Blister packing machine

Exercise

Identify Blister, Strip & ALU-ALU Pack in the next slide?????????

92

ReferencesPharmaceutical. Packaging Technology, Dean DA, Evans ER and Hall IH, Taylor & Francis Inc., 2000. Pharmaceutical Packaging Handbook. Bauer E, Taylor & Francis Inc., 2009.Pharmaceutical Technology, November, 2000www.slideshare.comwww.encyclopedia.comwww.google.com