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International Journal of Biological Macromolecules 72 (2015) 495–501

Contents lists available at ScienceDirect

International Journal of Biological Macromolecules

j ourna l h o mepa ge: www.elsev ier .com/ locate / i jb iomac

syllium arabinoxylan: Carboxymethylation, characterization andvaluation for nanoparticulate drug delivery

eenakshi Bhatia, Munish Ahuja ∗

rug Delivery Research Laboratory, Department of Pharmaceutical Sciences, Guru Jambheshwar University of Science and Technology, Hisar 125 001, India

r t i c l e i n f o

rticle history:eceived 17 July 2014eceived in revised form 25 August 2014ccepted 28 August 2014vailable online 6 September 2014

eywords:arboxymethylated psyllium arabinoxylanhitosanolyelectrolyte nanoparticles

a b s t r a c t

The objective of present investigation was to optimize the interaction between carboxymethylated psyl-lium arabinoxylan and chitosan to prepare polyelectrolyte naoparticles for drug delivery applications.Arabinoxylan extracted from psyllium was carboxymethylated by reacting with monochloroacetic acidunder alkaline conditions. Carboxymethylation of psyllium arabinoxylan was observed to increase itscrystallinity, improve thermal stability and decrease the viscosity. Further, the effect of concentrations ofcarboxymethylated arabinoxylan and chitosan on the particle size and particle size distribution of ibupro-fen loaded polyelectrolyte nanoparticles was screened using two-factor, three-level central compositeexperimental design. The results of optimization study revealed that the formation of nanometric poly-electrolyte is favored at the median level of carboxymethylated arabinoxylan and chitosan concentration.

The optimal concentrations of carboxymethylated arabinoxylan and chitosan were found to be 0.0779%(w/v) and 0.0693% (w/v) respectively, which provided polyelectrolyte particles of size 337.2 nm and poly-dispersity index 0.335. Further, polyelectrolyte complex nanoparticles were found to release ibuprofenover a prolonged period of 10 h following Higuchi’s square root release kinetics with the mechanism ofrelease being combination of diffusion and erosion of matrix.

© 2014 Elsevier B.V. All rights reserved.

. Introduction

Arabinoxylan (Ax) is an anionic polysaccharide consisting ofopolymers of arabinose and xylose. It is found abundantly inature and is used extensively both in traditional herbal remediesnd modern medicine. Psyllium is one such natural polysac-haride that contains arabinoxylan. The gel forming fraction ofsyllium seed husk is anionic polysaccharide comprising of glu-ose, galactose, arabinose, xylose, mannose and uronic acid inifferent concentrations range [1]. It has been reported as a poten-ial candidate in the treatment of number of ailments includingonstipation, diarrhea and irritable bowel syndrome, ulcerativeolitis, colon cancer, diabetes, hypercholesterolemia etc. [2]. Mod-fication of psyllium mucilage by techniques viz. ethylation [3],

ethacrylation [4], cross linking [5,6], thiolation [7], grafting [8,9]ave been explored for various applications in the field of phar-acy. Carboxymethyl functionalization of psyllium arabinoxylan

y carboxymethylation with monochloroacetate and its structuralharacterization has been carried out earlier [10].

∗ Corresponding author. Tel.: +91 1662263515.E-mail address: munishahuja17@yahoo.co.in (M. Ahuja).

ttp://dx.doi.org/10.1016/j.ijbiomac.2014.08.051141-8130/© 2014 Elsevier B.V. All rights reserved.

Carboxymethylated polysaccharides are usually more solu-ble, less viscous and have greater anionic character than thenative polysaccharide. Further the anionic character impartedon polysaccharides by carboxymethylation paves the way fortheir exploration in preparation of polyelectrolyte complexes withcationic polymers [11]. Safety considerations limit the use ofwater soluble and biocompatible polymers in preparation of poly-electrolyte complexes. Chitosan is the only natural polycationicpolysaccharide that meets these criteria [12]. It has been studiedextensively for formulating nanoparticles by ionotropic gelationwith polyanions. Chitosan–polyanion complexes limit the releaseof encapsulated drug more effectively than either the polyanionor chitosan alone. Polyelectrolyte complex nanoparticles of chi-tosan with hyaluronic acid [13], carboxymethyl gum kondagogu[14], carboxymethyl amylopectin [15], gum ghatti [16] and sodiumalginate [17] have been reported in literature but interaction withcarboxymethyl arabinoxylan has not yet been explored. Such poly-electrolyte complexes have been found to be useful for delivery ofdrugs, proteins [18], DNA and oligonucleotides [19].

In the present research work carboxymethyl functionaliza-

tion of psyllium arabinoxylan was done. The carboxymethylatedarabinoxylan (CMAx) was characterized by Fourier-transforminfra-red spectroscopy (FT-IR), thermogravimetric analysis (TGA),X-ray diffraction analysis (XRD), and scanning electron microscopy

4 of Biol

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96 M. Bhatia, M. Ahuja / International Journal

SEM). The degree of carboxymethyl substitution was determinedy classical acid wash method. The carboxymethylated psylliumrabinoxylan that is anionic in nature was further explored forts application as nanoparticulate drug carrier by forming poly-lectrolyte complex (PEC) on interacting it with chitosan usingbuprofen as model drug. The preparation of CMAx–chitosanEC nanoparticles was optimized by using 2-factor, 3-level cen-ral composite experimental design. The optimized batch of PECanoparticles was characterized for its morphology by transmis-ion electron micrography (TEM) and in vitro release behavior.

. Experimental

.1. Materials

Psyllium seed husk (Sidpur Sat Isabgol Factory, Gujarat, India)as purchased from local market. Ibuprofen, Poloxamer-407 and

hitosan were obtained as gift sample from Aventis Pharmatd. (Ankleshwar, India), Ranbaxy Research Laboratories (Gur-aon, India) and Central Fisheries Research Institute (Kochi, India)espectively. Monochloroacetic acid was purchased from Hi-Mediaaboratories Pvt. Ltd. (Mumbai, India). All other chemicals were ofeagent grade and used as received.

.2. Isolation of arabinoxylan

Arbinoxylan (Ax) was extracted from the seed husk of Plantagovata by alkali extraction method as described earlier [10]. Briefly,syllium husk was soaked in alkaline water (pH 12) overnight. The

nsoluble fraction was removed by passing it through muslin cloth.o this hydrochloric acid was added dropwise to gellify the solutiont a pH of 3. The gel thus obtained was washed with distilled waterill the pH of washings was neutral.

.3. Carboxymethylation of arabinoxylan

Briefly, Ax (1%, w/v) was dispersed in 20 ml of ice cold sodiumydroxide solution (45%, w/v) with continuous stirring for 30 min20]. An equal volume of monochloroacetate (75%, w/v) was addedo the above dispersion under continuous stirring followed by rais-ng the temperature to 75 ◦C, the reaction mixture was allowed toeact for 30 min. The reaction mixture was cooled and suspendedn aqueous methanol, the precipitate so obtained was neutralized

ith glacial acetic acid. Further, the carboxymethylated arabinoxy-an (CMAx) so obtained was washed with aqueous methanol (80%,/v) for at least three times and kept for drying in hot air oven at0 ◦C.

.4. Characterization of CMAx

.4.1. Fourier transform infra-red spectroscopy (FT-IR)Ax and CMAx samples were subjected to FT-IR spectroscopy

n a Fourier-transform infra-red spectrophotometer (Perkin-Elmer,pectrum) in range of 4000–500 cm−1 using KBr pellet method.

.4.2. Determination of degree of substitutionThe degree of carboxymethyl substitution was determined

sing classical acid wash method [21]. Briefly, 0.5 g of CMAx wasispersed in hydrochloric acid (7N) in 250 ml Erlenmeyer flask andhaken for 3–4 h. The suspended particles were removed by filtra-ion with muslin cloth and washed with aqueous methanol till the

ashings were neutral. The product was dried in oven at 40 ◦C. An

ccurately weighed quantity (0.120 g) of dried CMAx was dispersedn 10 ml of methanol (70%, v/v) in Erlenmeyer flask and stirredor 30 min. To this 30 ml of distilled water and 7.5 ml of sodium

ogical Macromolecules 72 (2015) 495–501

hydroxide (0.5N) was added and stirred for 4 h to dissolve the sam-ple completely. The excess of sodium hydroxide was back titratedwith hydrochloric acid (0.5N) using phenolphthalein as an indica-tor. The degree of carboxymethyl substitution was calculated usingthe equation:

DS = 0.162A

1 − 0.058A(1)

where

A = − (ml of NaOH × N1) − (ml of HCl × N2)gm wt of sample

(2)

where N1 and N2 are the normality of NaOH and HCl respectively.

2.4.3. ViscosityThe viscosity of aqueous dispersion of Ax (2%, w/v) and CMAx

(6%, w/v) was determined by using Brookefield viscometer (Brooke-field DV-E Viscometer) at different rpm using spindle no 6.

2.4.4. Thermal analysisThermogravimetric analysis (TGA) and differential scanning

calorimetery (DSC) of Ax and CMAx were recorded using a simul-taneous thermal analyzer (SDT, Q600, TA instruments, USA) in atemperature range of 25–600 ◦C under constant nitrogen purge of100 ml/min at a heating rate of 10 ◦C per min.

2.4.5. Powder X-ray diffraction analysis (PXRD)The Ax and CMAx powder samples were scanned using an

X-ray diffractometer (Miniflex 2, Rigaku, Japan) from 0◦ to 80◦

diffraction angle (2�) range under the following measurementconditions: source, nickel filtered Cu-K� radiation; voltage 35 kV;current 25 mA; scan speed 0.05 min−1, division slit 1.25◦, receivingslit 0.3 mm.

2.4.6. Scanning electron microscopy (SEM)The shape and surface morphology of Ax and CMAx were inves-

tigated using scanning electron microscope (JEOL, JSM-6100). Thesamples were coated with gold and mounted on a sample holder.

2.5. Preparation of CMAx–chitosan polyelectrolyte complexnanoparticles

CMAx was interacted with chitosan in acetic acid (2%, v/v)using ibuprofen as a model drug to prepare polyelectrolyte com-plex nanoparticles. Aqueous solutions of CMAx were preparedby adding the required quantity of CMAx in water and adjustingthe pH to 10–11 followed by sonication, while chitosan solu-tions were prepared by dissolving in acetic acid (2%, w/v) undersonication. CMAx–chitosan polyelectrolyte complex nanoparti-cles were prepared by dropwise addition of aqueous solutionsof CMAx (0.0125–0.1%, w/v) to the aqueous solutions of chitosan(0.0125–0.1%, w/v) containing Poloxamer-407 (0.5%, w/v) as stabi-lizer and ibuprofen (50%, w/w of the total polymer weight) undercontinuous stirring. The polyelectrolyte dispersions so obtainedwere sonicated at an amplitude of 50% for 5 min using probe soni-cator (Q55, QSonica, USA).

2.6. Experimental design

The preparation of CMAx–chitosan polyelectrolyte nanopar-ticles was optimized using 2-factor, 3-level central composite

experimental design (Table 1). The concentration of chitosan (X1)and CMAx (X2) were selected as the formulation variables, whileparticle size (Y1) and polydispersity index (PdI) (Y2) were chosenas response variables. Each independent variable was investigated

M. Bhatia, M. Ahuja / International Journal of Biological Macromolecules 72 (2015) 495–501 497

Table 1Particle size and entrapment efficiency of various batches of CMAx–chitosan polyelectrolyte nanoparticles.

Batch Conc. of chitosan(%, w/v) (X1)

Conc. of CMAx(%, w/v) (X2)

Particle size(d-nm) (Y1)

Polydispersityindex (PdI) (Y2)

Zeta potential Entrapmentefficiency (%)

1 0.0125 0.0125 510.3 0.73 29.9 96.842 0.1 0.0125 947 0.845 40.7 97.323 0.0125 0.1 794.9 0.583 −16 96.914 0.1 0.1 429.4 0.224 32.8 95.395 0.0125 0.0563 531.8 0.692 16.8 95.696 0.1 0.0563 417.4 0.522 37 97.387 0.0563 0.1 516.7 0.761 47.7 93.908 0.0563 0.0563 405.7 0.224 28.4 95.999 0.0563 0.0563 315.1 0.264 33.9 96.18

10 0.0563 0.0563 332.7 0.276 29.5 96.15

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3429 cm due to OH stretching of alcohols. The peaks appearingat 2945 cm−1 and 2920 cm−1 may be attributed to CH stretch-ing, while a peak appearing at 1600 cm−1 can be ascribed to C Ostretch. On the other hand peaks appearing at 1398 cm−1 can be

11 0.0563 0.0563 330.812 0.0563 0.0563 345

13 0.0563 0.0563 359.2

t three levels (i.e. −1, 0, +1). The experimental design and statisti-al analysis of the data was done by using Design Expert softwareVersion 7.0).

.7. Characterization of carboxymethyl arabinoxylan–chitosanolyelctrolyte complex nanoparticles

Ibuprofen-loaded CMAx–chitosan polyeletrolyte complexanoparticles were evaluated for particle size analysis, poly-ispersity index (PdI), zeta potential and drug entrapmentfficiency.

.7.1. Particle size analysisThe average particle size, particle size distribution (PdI) and zeta

otential of nanoparticles was measured using Zetasizer (Nano ZS0, Malvern Instrument, UK) at 25 ◦C. The measurements were done

n automated mode with equilibration time of 120 s.

.7.2. Entrapment efficiencyThe entrapment (%) of ibuprofen in CMAx–chitosan

olyeletrolyte complex was determined by separating theree drug from nanoparticles by centrifugation at 15,000 rpm for0 min by cooling centrifuge (C-24 BL, Remi Instruments, Mumbai,ndia). The clear supernatant was analyzed for the contents ofnentrapped ibuprofen by measuring the absorbance at 221 nm

n a UV–vis spectrophotometer (Cary 5000, Varian Australia). Thentrapment efficiency was calculated as follows:

E (%) = Ibut − Ibus

Ibut× 100 (3)

where Ibut is the total amount of drug used in the preparation ofolyelectrolyte complex nanoparticles and Ibus is the unentrapped

buprofen present in the supernatant.

.7.3. Transmission electron microscopy (TEM)The morphology of optimized batch of ibuprofen-loaded

MAx–chitosan polyeletrolyte complex nanoparticles was stud-ed using TEM (Hitachi H7500). The micrographs were taken at anccelerating voltage of 200 kV.

.7.4. In vitro drug release studyIn vitro release of ibuprofen from the optimized formulation and

rug solution was carried out by dialysis sac method by placing anccurately measured volume of drug and nanoparticles (3 ml) inhe dialysis tubing (cut off 10,000 kDa) [22]. The dialysis tube was

ied to the paddle of USP type II dissolution apparatus (TDL–08L,lectrolab, India) and immersed in 250 ml of dissolution mediumphosphate buffer pH 7.2). The dissolution media was maintained at7 ◦C ± 0.5 ◦C with continuous stirring at 50 rpm. An aliquot of 5 ml

0.347 33.2 96.150.258 30.9 96.100.244 32.9 96.12

sample was withdrawn at various time intervals and the media vol-ume was maintained by adding equal volumes of fresh media. Theconcentration of ibuprofen in the samples was determined spec-trophotometrically by measuring absorbance at 221 nm.

3. Results and discussion

Carboxymethylation of polysaccharides is reported to influ-ence their aqueous solubility, viscosity, swelling behavior andbioadhesion [20]. In the present study psyllium arabinoxylan wascarboxymethylated by etherification reaction by reacting usingmonochloroacetic acid under alkaline conditions. The yield of car-boxymethylated product (i.e. CMAx) was found to be 84%. Thedegree of carboxymethyl substitution as determined by classi-cal acid wash method was found to be 0.744 of carboxymethylgroups/g.

Fig. 1 exhibits the FT-IR spectra of Ax and CMAx. The spec-tra of Ax shows a broad absorption band at 3412 cm−1 whichmay be attributed to stretching of alcohols. The peak appearingat 2926 cm−1 can be ascribed to CH stretch of alkanes, whilethe peak at 1465 cm−1 can be attributed to inplane OH bendingvibrations. The peaks appearing at 1409 cm−1 and 1377 cm−1 aredue to bending of CH2 and CH respectively. The polymer back-bone bendings are represented by peaks at 896 cm−1, 794 cm−1, and613 cm−1. The spectra of CMAx exhibit a broad absorption band at

−1

Fig. 1. FT-IR spectra of Ax and CMAx.

498 M. Bhatia, M. Ahuja / International Journal of Biological Macromolecules 72 (2015) 495–501

nd (c)

aab

mCco29aemt(rsfgoiATfOTs

Fig. 2. (a) DSC, (b) thermogravimetric a

scribed to stretching of carboxylate anion, while peaks appearingt 898 cm−1, 771 cm−1 and 576 cm−1 may be assigned to polymerackbone bendings.

Fig. 2a–c presents the differential scanning calorimetry, ther-ogravimetric and first derivative curves respectively of Ax and

MAx. The thermal curve of Ax is typical of amorphous substancesharacterized by a broad endotherm at 70.29 ◦C with heat of fusionf 181.3 J/g followed by an exotherm at 258.50 ◦C with heat flow of40.1 J/gm. The DSC curve of CMAx displays a broad endotherm at2.45 ◦C with heat of fusion of 413.8 J/g followed by an exothermt 306.24 ◦C with heat of fusion of 179.7 J/g. Thus, the shift in thendothermic and exothermic transition temperature indicate thatodification of Ax has taken place. Different stages of decomposi-

ion of Ax and CMAx can be visualized from the thermogravimetricFig. 2b) and first derivative (Fig. 2c) curves. The weight loss occur-ing below 100 ◦C is mainly due to the loss of water from theamples. Table 2 details the various thermogravimetric parametersrom various steps of degradation as evaluated from the thermo-ram. The first stage of Ax decomposition is characterized by Tmax

f 54.44 ◦C with weight loss of 3.71% followed by second stage hav-ng Tmax of 185.55 ◦C with weight loss of 9.12%. The third stage ofx decomposition shows Tmax of 226.58 ◦C with 8.59% weight loss.he major degradation of Ax backbone appears to occur during the

ourth stage with a major weight loss of 21.72% at Tmax of 272.58 ◦C.n the other hand CMAx shows first stage of decomposition withmax of 128.05 ◦C is characterized by 9.3% weight loss followed byecond stage with Tmax of 249.58 ◦C with weight loss of 8.55%. The

first derivative curves of Ax and CMAx.

third stage or the major degradation occur at Tmax of 323.57 ◦C ischaracterized by 29.71% weight loss and the fourth stage of degra-dation with Tmax of 402.17 ◦C is characterized by weight loss of5.14%. Further, temperature for 50% decomposition i.e. T50 wasfound to be 307.2 ◦C and 359.5 ◦C for Ax and CMAx respectivelywhich indicate higher thermal stability of CMAx. Moreover, at theend of analysis i.e. at 600 ◦C, 30.56% and 38.79% of residue was leftof Ax and CMAx which confirms higher thermal stability of CMAx.Thus thermal stability of Ax is improved on carboxymethylation.

Fig. 3 displays the X-ray diffraction spectra of Ax and CMAx. X-ray diffractogram of Ax is typical of amorphous materials with nosharp peaks while the diffractrogram of CMAsx shows three char-acteristics sharp peaks at 32◦, 46◦, 56◦ and 75◦ (2�) which indicatesincrease in crystallanity of Ax on carboxymethylation.

Fig. 4a and b displays surface morphology of Ax and CMAx,examined under a scanning electron microscope. A close exami-nation of surface morphology reveals that surface of Ax is fibrousand striated while the micrograph of CMAx appears to be roughand porous.

Fig. 5 compares the viscosities of aqueous dispersion of Ax (2%,w/v) with CMAx (6%, w/v) determined using spindle number 6 ina Brookefield viscometer. Carboxymethylation of Ax results in pro-found fall in its viscosity. The viscosities of CMAx 2% (w/v) and 4%

(w/v) was too small to be measured in the range of Brookefield vis-cometer. Even a three-fold higher concentrated dispersion of CMAx(i.e. 6%, w/v) could not achieve the viscosity comparable to Ax. Thedrop in viscosity of Ax on carboxymethylation can be explained by

M. Bhatia, M. Ahuja / International Journal of Biological Macromolecules 72 (2015) 495–501 499

Table 2Thermogravimetric analysis of Ax and CMAx.

CMAx Ax

Tonset (◦C) Tmax (◦C) Tend (◦C) �W Tonset (◦C) Tmax (◦C) Tend (◦C) �W

31.43 128.05 236.56 9.3 32.97 54.44 75.52 3.71236.56 249.58 284.08 8.55 75.52 185.55 216.99 9.12248.08 323.57 351.56 29.71 216.99 226.58 238.08 8.59351.56 402.17 430.15 5.14 238.08 272.58 328.56 21.72Wr = 38.79%, T50 = 359.5 ◦C Wr = 30.56%, T50 = 307.2 ◦C

Wr , residual weight; T50, temperature for 50% decomposition; Tonset, temperature of onset of degradation stage; Tmax, maximum temperature; Tend, temperature at the endof degradation stage.

ttte

icat

atctCptd

pepmrrde

S

Fig. 3. X-ray diffraction spectra of (a) Ax and (b) CMAx.

he fact that carboxymethylation of Ax imparts anionic character onhe Ax backbone which because of coloumbic repulsions betweenhe backbone chains results in fall in viscosity. Similar results werearlier reported for carboxymethyl gum kondagogu [14].

CMAx was found to interact with chitosan. However no suchnteraction was observed between the psyllium arabinoxylan andhitosan. Carboxymethylation increases the anionic character onrabinoxylan chain making it amenable to react with cationic chi-osan.

In the present investigation the interaction between the CMAxnd chitosan have been optimized so that nanometric polyelec-rolytes are formed. During preliminary trials it was observed thatoncentration of CMAx and chitosan influence the size of polyelec-rolyte particles. Therefore, the concentration of chitosan (X1) andMAx (X2) were selected as formulation variables to optimize thereparation of the polyelectrolyte particles having minimum par-icle size and PdI and maximum entrapment of ibuprofen, a modelrug.

Table 1 shows the results of particle size (Y1), PdI (Y2), zetaotential and entrapment efficiency (%) of CMAx–chitosan poly-lectrolyte complex nanoparticles prepared as per the designrotocol. The responses generated were fitted into various polyno-ials models using the experimental design. It was observed that

esponse particle size (Y1) and PDI (Y2) fitted best into quadraticesponse surface model after square root transformation of theata. The polynomial models for the responses Y1 and Y2 can bexpressed by the equation:

qrt(Y1) = 18.24 − 0.32X1 − 1.17X2 − 3.91X1X2 + 3.76X21 + 3.45X2

2

(4)

Fig. 4. Scanning electron micrograph of (a) Ax and (b) CMAx.

Sqrt(Y2) = 0.55 − 0.056X1 − 0.16X2 − 0.089X1X2 + 0.17X21

+ 0.064X22 (5)

Table 3 summarizes the results of ANOVA on the responsesurface model. The polynomial model were found to be signif-icant (P < 0.0500) with non-significant lack of fit (P > 0.05). Thehigher value of R2 (>0.9) indicated good correlation between theexperimental and predicted response. Adequate precision whichmeasures the signal to noise ratio was much above the requiredvalue of 4, which indicate the adequate signal and model fit to

navigate the design space.

Fig. 6a and b) displays the combined effect of concentration ofCMAx and chitosan on particle size and PdI respectively. It canbe inferred from the plot (Fig. 6a) that there exist a curvilinear

500 M. Bhatia, M. Ahuja / International Journal of Biological Macromolecules 72 (2015) 495–501

Table 3Model summary statistics.

Response factors Model Lack of fit

F-value Prob. > F R2 Adeq. prec. C.V. (%) F-value Prob. > F

Y1 (z-avg) 62.09 0.0001 0.9780 22.765 3.59 5.57 0.0653Y2 (PdI) 14.60 0.0014 0.9125 11.278 10.20 6.31 0.0536

adeq. prec., adequate precision; c.v., coefficient of variance

rIttbfm

lPotmv

dCofbbt(nPdt

sCct

np

Fig. 6. Response surface plots showing combined effect of concentrations of CMAxand chitosan on (a) particle size and (b) polydispersity index.

Fig. 5. Rheological behavior of Ax and CMAx.

elationship between the independent and dependent variables.t is vindicated from the plot that at lower levels of CMAx or chi-osan increasing the concentration of another electrolyte results inhe increase in particle size of polyelectrolyte. Further, the reactionetween equivalent concentrations (w/v) of chitosan and CMAxavors the smaller size with minimum particle size achievable at

edian levels of both CMAx and chitosan concentration.The effect (Fig. 6b) of CMAx on PdI is more prominent at higher

evels of chitosan than at lower levels of chitosan. Further, the lowerdI (0.335) i.e. monodisperse particles are formed at higher levelsf CMAx and chitosan. PdI gives an indication of particle size dis-ribution of suspension, PdI < 0.4 is considered as an indicator of

onodispersity. The results of drug entrapment studies revealed aery high entrapment of ibuprofen in the polyelectrlyte particles.

A numerical optimization tool of Design Expert Software usingesirability approach was employed to prepare ibuprofen loadedMAx–chitosan PEC nanoparticles with desirable particle size. Theptimization of independent variables was done with constraintsor minimum particle size and PdI. The parameters as suggestedy the optimization tool were employed for preparing optimizedatch of nanoparticles. The suggested parameters were concen-ration of chitosan (0.0693%,w/v) and concentration of CMAx0.0779%, w/v) that provided ibuprofen loaded CMAx–chitosan PECanoparticles of particle size of 337.2 nm (pred. 330.026 nm) andDI of 0.335 (pred. 0.224). The closer agreement between the pre-icted and observed values indicate the high prognostic ability ofhe polynomial model.

Fig. 7 displays the transmission electron micrographshowing morphology of optimized batch of ibuprofen loadedMAx–chitosan polyelectrolyte particles. It can be observed thathitosan and CMAx particles interact with each other to form ovoido spherical shaped aggregates having diameter of 100 nm.

The optimized batch of ibuprofen loaded CMAx–chitosananosuspension was evaluated for drug release behavior. Fig. 8 dis-lays the in vitro release profile of ibuprofen from nanoparticulate

Fig. 7. Tranmission electron micrograph of ibuprofen-loaded CMAx–chitosannanoparticles polyelectrolyte complex.

M. Bhatia, M. Ahuja / International Journal of Biological Macromolecules 72 (2015) 495–501 501

Table 4Modeling and release kinetics of ibuprofen from polyelectrolyte nanosuspension.

Formulation Zero order First order Higuchi Korsemeyer–Peppas

R2 R2 R2 R2 n

Ibu sol 0.912 0.485

PEC 0.967 0.530

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[[[20] A. Kumar, M. Ahuja, Carbohydr. Polym. 90 (2012) 637–647.

ig. 8. In vitro release profile of ibuprofen in phosphate buffer pH 7.2 at 37 ◦C.

uspension. The nanoparticulate suspension provided a prolongedelease of ibuprofen with 98.56% of drug getting released over aeriod of 12 h.

To study the limiting effect of dialysis membrane the releaseehavior of nanosuspension is compared with equivalent con-entration of drug solution. The release of ibuprofen fromanoparticulate suspension and from drug solution was fitted intoarious kinetic models to estimate their release kinetics and mech-nism of release (Table 4). The results of release rate data for theormulation fitted best into Higuchi model (R2 = 0.974) of releaseinetics. Further, the value of ‘n’ (0.43 < n < 0.85) the release expo-ent of Korsemeyer and Peppas equation indicates that the releasef ibuprofen from spherical particles of nanosuspension occurs byiffusion and erosion from the matrix [23].

. Conclusion

Carboxymethylated arabinoxylan was prepared by etherifica-

ion of psyllium arabinoxylan with monochloroacetic acid. Theormation of carboxymethylated arabinoxylan was confirmedy FT-IR spectroscopy. Carboxymethylation of arabinoxylan wasound to increase crystallinity and thermal stability, decrease

[[

[

0.987 0.956 0.8020.974 0.972 0.647

viscosity and render it anionic in nature. CMAx interacts with chi-tosan to form polyelectrolyte nanoparticles. The polyelectrolytenanoparticles were found to release model drug following Higuchisquare root kinetics in a sustained manner. On the basis of this studyit can be concluded that interaction between CMAx and chitosancan be employed for preparing nanoparticulate drug carrier.

Acknowledgement

The authors are grateful to the University Grant Commission,New Delhi (No. 41-705/2012(SR)) for providing financial grantsunder the Major Research Project scheme.

References

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