Journal of Biomaterials and Nanobiotechnology, 2011, 2, 414-425
doi:10.4236/jbnb.2011 24051 Published Online October 2011 (
Copyright © 2011 SciRes. JBNB
Synthesis and Characterization of
Chitosan-Polyvinyl Alcohol Blended with Cloisite
30B for Controlled Release of the Anticancer Drug
Umesh Kumar Parida1, Ashok Kumar Nayak2, Birendra Kumar Binhani3, P. L. Nayak1*
1P. L. Nayak Research Foundation, Neelachal Bhavan, Cuttack , India; 2P. L. Nayak Research Foundation, Neelachal Bhavan, Bidy-
adharpur, Cuttack, India; 3KIIT School of Biotechnology, KIIT University, Bhubaneswar, India.
Email: *,,, *
Received May 10th, 2011; revised June 27th, 2011; accepted July 30th, 2011.
In the present research program, polymer nanocomposites have been used as the drug carrier for delivery systems of
anticancer drug. Chitosan (Cs) and Polyvinyl Alcohol (PVA) with different ratios were blended with different wt% of
Cloisite 30B solution by solvent casting method. Glutaraldehyde with different wt% was added to the blended solution
as a crosslinking agent. Cloisite 30B was incorporated in the formulation as a matrix material component which also
plays the role of a co-emulsifier in the nanocomposite preparation. Curcumin with different concentrations were loaded
with CS-PVA/C 30B nanocomposites for studying the in-vitro drug delivery systems. Morphology and structure charac-
terization of nanocomposites were investigated by fourier transmission infra red spectroscopy (FTIR), scanning elec-
tron microscope (SEM), tensile strength and water uptake capacity. The drug release was studied by changing time, pH
and drug concentrations. The kinetics of the drug release was studied in order to ascertain the type of release mecha-
nism. Based on the diffusion as well as the kinetics, the mechanism of the drug release from the composite matrix has
been reported.
Keywords: Chitosan, PVA, C 30B, Glutaraldehyde, Curcumin, Drug Delivery
1. Introduction
Carrier-mediated drug delivery has emerged as a power-
ful methodology for the treatment of various pathologies.
The therapeutic index of traditional and novel drugs is
enhanced via the increase of specificity due to targeting
of drugs to a particular tissue, cell or intracellular com-
partment, the control over release kinetics, the protection
of the active agent or a combination of the above. Poly-
mer composites were proposed as drug carriers over 30
years ago and have received growing attention since,
mainly due to their stability, enhanced loading capabili-
ties and control over physicochemical properties [1-2]. In
addition to systemic administration, localized drug re-
lease may be achieved using macroscopic drug depots
close to the target site. Among various systems consid-
ered for this approach, in situ-forming biomaterials in
response to environmental stimuli have gained consider-
able attention, due to thenon-invasive character, reduc-
tion of side effects associated with systemic administra-
tion and better control over biodistribution [3]. In recent
years biodegradable polymers have attracted attention of
researchers to be used as carriers for drug delivery sys-
Poly(vinyl alcohol), PVA, is a non-toxic, water-solu-
ble synthetic polymer and has good physical and chemi-
cal properties and film-forming ability [4].The use of this
polymer is important in many applications such as con-
trolled drug delivery systems, membrane preparation,
recycling of polymers and packaging. Studies on the me-
chanism of dissolution and changes in crystallinity and
swelling behaviour of PVA and its physical gel-forming
capabilities, have been carried out [5]. PVA has bioi-
nertness and it has many uses in medical applications
such as artificial pancreas, hemodialysis, nanofilteration,
synthetic vitreous and implantable medical device. Anti-
thrombogenicity, cell compatibility, blood compatibility
and biocompatibility of PVA have been studied exten-
Synthesis and Characterization of Chitosan-Polyvinyl Alcohol Blended with Cloisite 30B for Controlled Release 415
of the Anticancer Drug Curcumin
sively [3,5,6].
Chitosan (Cs) is a natural polysaccharide formed dur-
ing the deacetylation of chitin in alkaline condition. It
comprises an unbranched chain consisting of β-(1, 4)-2-
amino-2-deoxy-D-glucopyranose, and it is a unique basic
linear polysaccharide [4,7-9]. The hydrophilicity of the
polymer due to amine functionality in most repeat units
makes the polymer soluble in dilute acid [10]. Chitosan
is widely used in food and pharmaceutical industry and
in biotechnology. This polysaccharide has been exten-
sively studied in the field of biomaterials and because of
its biological properties, biodegradability, bioactivity and
biocompatibility it has attracted much attention [11-16].
Polymer blending is one of the useful ways to have new
material with required properties and there have been
great scientific and commercial progress in the area of
polymer blends. This was driven by the realization that
new molecules are not always required to meet the need
for new materials and blending can usually be imple-
mented more rapidly and economically than the devel-
opment of new materials [17,18].
Blends of synthetic and natural polymers represent a
new class of materials and have attracted much attention
especially in bioapplication as biomaterial. The success
of synthetic polymers as biomaterial relies mainly on
their wide range of mechanical properties, transformation
processes that allow a variety of different shapes to be
easily obtained and low production costs [2]. Biological
polymers represent good biocompatibility but their me-
chanical properties are often poor, the necessity of pre-
serving biological properties complicates their process-
ability and their production costs are very high [19,20]. It
is favorable that intermolecular interaction exists be-
tween two polymer species. Hydrophilicity of the syn-
thetic polymers has great influence on the blend prepara-
tion and properties. Surface and bulk hydrophilicity of
blended polymers affect mainly their biological behav-
iour. Bulk hydrophilicity of polymers may be studied by
water uptake ratio, and surface hydrophilicity could be
measured by surface tension and water contact angle.
The PVA is a hydrophilic and water-soluble polymer and
chitosan contains hydroxyl and amine groups. Some as-
pects, of their blend properties have been studied [21].
Cloisite 30B is methyl, tallow, bis-2 hydroxyethyl,
quaternary ammonium, where tallow is 65% C18, 30%
C16, and 5% C14. Clay minerals are widely used materi-
als in drug products as delivery agents [22]. Montmoril-
lonite (MMT) can provide mucoadhesive capability for
the nanoparticle to cross the gastrointestinal (GI) barrier
[23]. MMT is also a potent detoxifier, which belongs to
the structural family of 2:1 phyllosilicate. MMT could
absorb dietary toxins, bacterial toxins associated with
gastrointestinal disturbance, hydrogen ions in acidosis
and metabolic toxins such as steroidal metabolites asso-
ciated with pregnancy [24].
Curcumin is a hydrophobic polyphenol derived from
turmeric: the rhizome of the herb Curcuma longa. Che-
mically, it is a bis-a, b-unsaturated diketone (commonly
called diferuloylmethane) that exhibits keto-enol tauto-
merism, having a predominant keto form in acidic and
neutral solutions and a stable enol form in alkaline media.
Commercial curcumin is a mixture of curcuminoids, con-
taining approximately 77% diferuloylmethane, 18% de-
methoxycurcumin, and 5% bisdemethoxycurcumin [25-
27]. Traditionally, turmeric and other curcuminoids have
been used in therapeutic preparations for various ail-
ments in different parts of the world. Numerous thera-
peutic effects of curcumin/turmeric have been confirmed
by modern scientific research. Herein, we present a sys-
tematic review of the clinical and experimental data on
the use of curcumin in the treatment of cancer [28]. Cur-
cumin possesses antioxidant, anti-inflammatory, anticar-
cinogenic, and antimicrobial properties, and suppresses
proliferation of a wide variety of tumor cells. Several
clinical trials dealing with cancer have addressed the
pharmacokinetics, safety, and efficacy of curcumin in
humans. Despite extensive research and development,
poor solubility of curcumin in aqueous solution remains
a major barrier in its bioavailability and clinical efficacy.
Being hydrophobic in nature, it is insoluble in water but
soluble in ethanol, dimethylsulfoxide, and acetone. To
increase its solubility and bioavailability, attempts have
been made through encapsulation in liposomes, poly-
meric and lipo-NPs, biodegradable microspheres, cyclo-
dextrin, and hydrogels [29-34].
In this study, blended films were prepared from PVA
and Cs compounded with Cloisite 30 B with varying
concentrations. The FTIR, SEM, mechanical and water
uptake properties of these films were investigated. The
blends were mixed with different amount of curcumin
and the drug delivery system was investigated at diffe-
rent pH medium and the various kinetic parameters have
been computed. The plausible mechanism of drug deli-
very has been postulated based on the kinetic data.
2. Experimental
2.1. Materials
PVA Samples was purchased from Aldrich Co. (with 99%
hydrolyzed, Mw 85,000 - 146,000). A sample of chitosan
(Cs) was from India Sea Foods, Kerala, India, with
85.6% degree of deacetylation and viscosity of 115 cps
in 1% acetic acid. Cloisite 30B was procured from Sou-
thern Clay, USA. Curcumin was a generous gift from VINS
Copyright © 2011 SciRes. JBNB
Synthesis and Characterization of Chitosan-Polyvinyl Alcohol Blended with Cloisite 30B for Controlled Release
of the Anticancer Drug Curcumin
Bioproducts, Medak, Andhra Pradesh. All other chemi-
cals used were analytical grade.
2.2. Methods
The polymer films were prepared by solvent casting
method. Cs solutions were prepared by dissolving chito-
san in 1% aqueous acetic acid solution at room tempera-
ture with stirring. The PVA was dissolved in hot water to
form 10 wt% polymer solutions. Both polymer solutions
were filtered using sintered glass and the solutions were
carefully mixed at various ratios. The weight fraction of
PVA was different to obtain a series of blends with 0 to
100 %wt PVA in the resulting solution as listed in Table
The filtered solution was placed under vacuum and it
was cast on a clean glass plate. Samples were dried at
60 ˚C, immersed in NaOH (1N) and saturated Na2SO4 to
remove residual materials then washed with deionized
water to remove alkali and unreacted materials and fi-
nally dried at 60˚C for 24 h. For cross-linking of the
films a specific amount of glutaraldehyde was added to
the solution, mixed thoroughly and it was cast as above.
2.3. Drug Loading
Curcumin-loaded Cs-PVA/ C 30B nanocomposites were
prepared by emulsion/solvent evaporation method. In
short, curcumin of different loadings, i.e., 1 wt%, 3 wt%,
5 wt%, 7 wt% and 10wt% were dissolved in ethanol with
(80:20) Cs-PVA/C 30B. The formed solution was poured
into a labeled petri dish and allowed to evaporate the
solvent overnight at room temperature. This compound
was used for drug delivery purposes.
2.4. Dissolution Experiments
Dissolution experiments were performed at 37˚C using
the dissolution tester (Disso test, Lab India, Mumbai,
India) equipped with six paddles at a paddle speed of 100
rpm. About 900 ml of phosphate buffer solution (pH 1.2
and 7.4) was used as the dissolution media to stimulate
gastrointestinal tract (GIT) conditions. A 5 ml aliquot
was used each time for analyzing the curcumin content at
a fixed time interval. The dissolution media was replen-
ished with a fresh stock solution. The amount of curcu-
min released was analyzed using a UV spectrophotome-
ter (Systronics, India) at the λ max value of 490 nm.
2.5. Drug Release Mechanism from Matrices
From time to time, various authors have proposed several
types of drug release mechanisms from matrices. It has
been proposed that drug release from matrices usually
implies water penetration in the matrix, hydration, swell-
ing, diffusion of the dissolved drug (polymer hydro fu-
Table 1. The ratio of poly (vinyl alcohol) (PVA), chitosan
(Cs) and the amount of glutaraldehyde (GA) in different
Sample Cs (wt%) PVAL
(wt%) GA × 10 -5
(mol/g polymer)
S1 100 0 0
S1 (GA1) 100 0 2.4
S2 75 25 0
S2 (GA1) 75 25 2.4
S3 50 50 0
S3 (GA1) 50 50 2.4
S3 (GA2) 50 50 5
S3 (GA3) 50 50 7.5
S4 25 75 0
S4 (GA1) 25 75 2.4
S5 0 100 0
S5 (GA1) 0 100 2.4
sion), and/or the erosion of the gelatinous layer. Several
kinetic models relating to the drug release from matrices,
selected from the most important mathematical models,
are described over here. However, it is worth mention
that the release mechanism of a drug would depend on
the dosage from selected, pH, nature of the drug and, of
course, the polymer used.
1) Zero - Order Kinetics [35].
2) First - Order Kinetics [35,36].
ln 100ln100W kt
3) Hixon-Crowel’s Cube- Root Equation (Erosin Mo-
del) [36].
13 13
100 100W kt
4) Higuchi’s Square Root of Time Equation (Diffusion
Model) [37].
Wkt (4)
5) Power Law Equation (Diffusion/ Relaxation model)
tM kt
Mt/M is the fractional drug release into dissolution
medium and k5 is a constant incorporating the structural
and geometric characteristics of the tablet. The term ‘n’
is the diffusional constant that characterizes the drug
release transport mechanism. When n 0.5, the drug
diffused and released from the polymeric matrix with a
quasi-Fickian diffusion mechanism. For n 0.5, an
anomalous, non-Fickian drug diffusion occurs. When n
1, a non-Fickian, case II or Zero - order release kinetics
could be observed.
opyright © 2011 SciRes. JBNB
Synthesis and Characterization of Chitosan-Polyvinyl Alcohol Blended with Cloisite 30B for Controlled Release 417
of the Anticancer Drug Curcumin
3. Characterization
3.1. Fourier Transmission Infra Red
Spectroscopy (FTIR)
The FTIR spectrum of the chitosan, alginate, and chito-
san-PVA blend was obtained using a BIORAD-FTS-7PC
type FTIR spectrophotometer.
3.2. Scanning Electron Microscopy (SEM)
The blending of the Chitosan-PVA composites contain-
ing different concentrations was characterized using
SEM (440, Leica Cambridge Ltd., Cambridge, UK). The
powdered specimens were placed on the Cambridge
standard aluminium specimen mounts (pin type) with
double-sided adhesive electrically conductive carbon
tape (SPI Supplies, West Chester, PA). The specimen
mounts were then coated with 60% Gold and 40% Palla-
dium for 30 seconds with 45 mA current in a sputter
coater (Desk II, Denton Vacuum, Moorestown, NJ). The
coated specimens were then observed on the SEM using
an accelerating voltage of 20 kV at a tilt angle of 30˚ to
observe the microstructure of the chitosan-PVA compos-
ite blends.
3.3. Tensile Properties
All the samples were prepared as thin films and their ten-
sile strength and tensile strain in the dry and wet states
were carried out using an Instron (model 5566, V = 5
mm/min and d = 10 mm). For testing in wet state, all the
films were placed in phosphate buffer saline (PBS) solu-
tion (pH = 7.2 - 7.4) for 30 min and then their tensile
strength and tensile strain were measured. Film strips in
specific dimensions and free from air and bubble or
physical imperfection were held between two clamps po-
sitioned at a distance 10 mm. During measurement, the
sample was pulled by top clamp at a rate 5 mm/min. The
thickness of the film sample was measured using a mi-
crometer at five locations (center and four corners), and
the mean thickness was calculated. Samples with air
bubbles, nicks or tears and having mean thickness varia-
tion of greater than 5% were excluded from analysis.
3.4. Water Uptake
Water absorption of the polymer-drug conjugates was
measured following ASTM D 570-81. The samples were
preconditioned at 50˚C for 24 h and then cooled in a des-
iccator before being weighed. The preconditioned sam-
ples were submerged in distilled water at 25˚C for 24 h.
The samples were removed and dried with a paper towel
before weighing. Water absorption was calculated as a
percentage of initial weight. The soluble material loss
was checked by weighting the specimens after drying
them in an oven at 50˚C for another 24 h. The total water
absorption for 24 h was calculated including the soluble
material loss
% Swelling100
where, W1 = Weight of swollen composite after 24 hr.,
W2 = Weight of dry composite.
4. Results and Discussion
4.1. Fourier Transmission Infrared Spectroscopy
FTIR spectroscopy was used to assess the polymer che-
mical groups (chitosan and PVA) and investigating the
formation of crosslinked networks from the blends with
glutaraldehyde. Figure 1A shows the FTIR spectra rela-
tive to the chitosan, PVA and [Cs/PVA] blends. Figure
1Aa spectrum of pure chitosan shows peaks around 893
and 1156 cm–1 corresponding to saccharide structure [19].
In spite of several peaks clustering in the amide II peak
range from 1510 to 1570 cm–1, there were still strong
absorption peaks at 1658 and 1322 cm–1, which are
characteristic of chitosan and have been reported as am-
ide I and III peaks, respectively. The sharp peaks at 1383
and 1424 cm–1 were assigned to the CH3 symmetrical de-
formation mode. The broad peak at 1030 and 1080 cm-1
indicates the C-O stretching vibration in chitosan. An-
other broad peak at 3447 cm–1 is caused by amine N-H
symmetrical vibration, which is used with 1650 cm -1 for
quantitative analysis of deacetylation of chitosan. Peaks
at 2800 and 2900 cm–1 are the typical C-H stretch vibra-
tions [5]. The IR spectra of the Cs/PVA blended films
presented in Figure 1A(b), Figures 1A(c) and A(d) are
different from that of the chitosan because of the ioniza-
tion of the primary amino groups. There are two distinct
peaks at 1408 and 1548 - 1560 cm–1. Formation of the
1548 - 1560 cm–1 peak is the symmetric deformation of
NH3 resulting from ionization of primary amino groups
in the acidic medium whereas the peak at 1408 cm–1 in-
dicates the presence of carboxylic acid in the polymers.
The peaks at 1700 - 1725 cm–1 are characteristic of the
carboxylic acid. In the present study, the presence of
carboxylic dimmer was due to the acetic acid used for
dissolving the chitosan [6]. The peak at 1210 - 1300 cm–1
is due to the C=H vibration.
Hence, there is a significant reduction of intensities
from the main absorption bands related to chitosan, for
instance amine region (1500 - 1650 cm–1), as its content
was decreased from 100% (pure chitosan, Figure 1A–a),
75% (Figure 1A(b)), 50% (Figure 1A(c)), 25% (Figure
1A(d)) and 0% (pure PVA, Figure 1A(e)). The FTIR
Copyright © 2011 SciRes. JBNB
Synthesis and Characterization of Chitosan-Polyvinyl Alcohol Blended with Cloisite 30B for Controlled Release
of the Anticancer Drug Curcumin
Copyright © 2011 SciRes. JBNB
spectrum of pure PVA is shown in Figure 1A(e), where
all major peaks related to hydroxyl and acetate groups
were observed. More specifically, the broad band ob-
served between 3550 and 3200 cm–1 is associated with
the stretching O-H from the intermolecular and intra-
molecular hydrogen bonds. The vibrational band ob-
served between 2840 and 3000 cm–1 refers to the stretch-
ing C=H from alkyl groups and the peaks between 1750
and 1735 cm–1 are due to the stretching C=O and C-O
from acetate group remaining from PVA (saponification
reaction of polyvinyl acetate) [4]. Figure 1B shows the
FTIR spectra of Cs/PVA blend with a proportion of 25%
Chitosan and 75% PVA (curve-a), at two concentrations
of GA chemical crosslinker, 1% (curve-b) and 5% (curve-
c). It can be noted the bands at 1110, 1406, 1638 and
1650 cm–1 mainly associated with PVA, and also the
presence of peaks related to carboxylic acid and the im-
ines formed by the crosslinking reaction by glutaralde-
hyde of amine groups from chitosan. Moreover, an in-
crease in the intensity and a shift in the band associated
with the bend vibration of the CH2 (1406 cm–1) group
was observed. As expected, because the blend crosslink-
ing reaction was conducted at pH (4.00 ± 0.05), covalent
chemical bonds have preferentially occurred in the chi-
tosan amine groups and less in the PVA hydroxyl groups
[7]. Chemical crosslinking of the chitosan/PVA blends
can be explained by the Schiff base formation as verified
by the 1634 and 1550 cm–1 bands associated with the
C=N and NH2 groups, respectively [8]. All chitosan-
derived blends have shown a relative increase on their
imine band and simultaneous drop on the amine (-NH2)
band after chemical crosslinking with glutaraldehyde
[19]. The imine group was formed by the nucleophilic
reaction of the amine from chitosan with the aldehyde.
Figure 1C shows the evolution of imine groups as the
glutaraldehyde concentration is increased. The PVA re-
Figure 1. FTIR spectra of (a) the chitosan, (b) Cs/PVA/GA (1:3:0), (c) Cs/PVA/GA (1:1:0), (d) Cs/PVA/GA (:3:1:0), (e) PVA,
(B) FTIR spectra of Cs/PVA (1:3) bands without Chemical crosslinking (a) and chemical crosslinking with 1% (b) and 5 %
(c), (C) Evolution of vibration band from imine group (C=N) with the concentration of glutaraldehyde.
Synthesis and Characterization of Chitosan-Polyvinyl Alcohol Blended with Cloisite 30B for Controlled Release 419
of the Anticancer Drug Curcumin
action with GA resulted in significant alterations in the
bands regarding to hydroxyls (O-H), normally associated
with the acetal bridge formation [8].
4.2. Scanning Electron Microscope (SEM)
Figure 2 shows the surface area SEM images of chito-
san-PVA and chitosan-PVA/ C 30B membranes. No ob-
vious agglomeration of C 30B particles was observed in
Figures 4(a) and (b), which contain 1% and 2.5% of C
30B respectively, thus suggesting that C 30B particle can
be well dispersed in chitosan-PVA matrix and the fabri-
cated membrane can be considered as homogenous and
dense with no obvious phase separation. However, in
case of Figure 4(c), containing 5% of C 30B, the ag-
glomeration of various sizes of C 30B particles which
randomly dispersed within the chitosan-PVA matrix are
observed. Due to the randomness of particle distribution,
chitosan-PVA/C 30B (5%) can be regarded as quasi ho-
4.3. Tensile Properties
The tensile testing provides an indication of the strength
and elasticity of the films, which can be reflected by
strength and strain-at-break. The tensile strength and
strain- at-break of different samples in dry and wet states
were measured with Instron (Table 2). Blending (p <
0.05) improved tensile strength of PVA-Cs blend in dry
and wet states significantly. These results indicate that
blend films have higher tensile strength than pure Cs and
PVA films. Blending leads to an intermolecular interac-
tion between two polymers and this improves mechanical
strength of the blends. Kim and other research workers
[7,8] have also supported these results. Due to possibility
of interaction between -OH and -NH2 groups in these
two polymers, blending improves mechanical properties
of the films. As it can be seen in Table 2, the tensile
strength of S1 sample is 57.2 MPa which increases to
76.2 MPa for S2 sample (with 25 wt% PVA) and for S3
sample (with 50 wt% PVA ) increases to 71.6 MPa. PVA
Sample has more elongation-at-break, so with increasing
the PVA content in the blend, the flexibility of the films
were increased.
Cross-linking with glutaraldehyde improves tensile
strength and decreases tensile strain of the blend films.
By increasing glutaraldehyde concentration, the films be-
come more rigid and show less flexibility. It was found
that the cross-linking improves mechanical properties of
Cs as compared to PVA. The effect of glutaraldehyde to
improve tensile strength increases by increasing Cs con-
tent in the blend films. The crosslinking of S2 sample (25
wt% PVA) increased tensile strength by 20% in dry
Figure 2. SEM of chitosan/ PVA with (a) 1% C 30B, (b) 2.5 % C 30B and (c) 5% C 30B.
Copyright © 2011 SciRes. JBNB
Synthesis and Characterization of Chitosan-Polyvinyl Alcohol Blended with Cloisite 30B for Controlled Release
of the Anticancer Drug Curcumin
Table 2. Tensile strength and tensile strain -at-break for different samples.
Sample Tensile Dry Tensile Wet
Strength (MPa) Strain (%) Strength (MPa) Strain (%)
S1 57.2 ± 1.6 9.0 ± 1.0 15.8 ± 1.1 40.9 ±2.5
S1 (GA1) 71.4 ± 1.3 7.5 ± 0.8 21.6 ±1.6 31.7± 3.6
S2 78.2 ± 1.1 10.0 ±0.8 23.4 ±1.7 48.1 ± 2.9
S2 (GA1) 91.2 ±1.9 8.9 ± 1.2 31.5 ± 1.3 39.2 ± 3.1
S3 71.6 ±1.5 11.2 ± 1.4 19.0 ± 1.8 55.6 ± 3.7
S3 (GA1) 83.9 ± 2.3 10.0 ± 1.2 24.1 ± 1.4 46.5 ± 4.1
S3 (GA2) 95.3 ± 2.0 8.2 ± 0.9 - -
S3 (GA3) 113.7 ± 1.2 4.1 ± 1.1 - -
S4 67.1 ± 1.1 14.8 ± 1.6 16.1 ± 1.3 68.0 ± 3.1
S4 (GA1) 76.7 ±1.4 13.3 ± 1.1 19.3 ± 1.5 63.2 ± 2.9
S5 53.3 ± 1.9 16.2 ± 1.1 8.0 ± 1.5 80.1 ± 2.5
S5 (GA1) 58.1 ± 2.5 15.4 ± 0.9 9.2 ± 1.0 76.1 ± 1.9
state and 36% in wet state. This percentages for S4 sam-
ples (75%wt PVA), in the dry and wet states were 13%
and 20%, respectively. Similar trend was observed in the
wet state. The cross-linking of chitosan and PVA with
glutaraldehyde is shown in Figure 3.
4.4. Water Uptake
As shown in Table 3 water uptake of all samples were
increased by increasing the PVA content. This is attrib-
uted to the increasing of hydrophilic groups (-OH) in the
blends. Cross-linking with GA decreases water uptake in
all samples. By increasing GA concentration more hy-
droxyl and amino groups of polymers in the blends are
consumed due to the cross-linking reactions and blends
showing less capability for hydrogen bonding. The effect
of pH on water uptake was also studied. The water up-
take increased when pH decreased. The effect of pH on
increasing water uptake is more significant for samples
with more Cs content (Figure 4). The effect of pH on
water uptake was decreased by increasing GA concentra-
tion (Figure 5). This could be explained by the fact that
in acidic medium the amino groups of Cs (-NH2) are
protonized (-NH3
+) so that the hydrogen bonds between
Cs and PVA are inhibited, therefore, the network has
more potential for hydrogen bonding with surrounding
water. Also, Cs molecules in the acidic condition are
being uncoiled and form rods [3], which, might be an-
other parameter to enhance hydrogen bonding with water.
It seems likely that pH has more effect to increase water
uptake for Cs in comparison with PVA.
5. In-Vitro Drug Release
5.1. Effect of pH, Time and Drug loading
In order to investigate the effect of pH on the swelling of
Cs-PVA/C 30B composite (2.5%), we have measured the
% cumulative release in both pH 1.2 and 7.4 media. Cu-
mulative release data presented in Figure 6 indicate that
by increasing the pH from 1.2 to 7.4, a considerable in-
crease in the cumulative release is observed for all com-
posites. From Figures 6(a) and (b), it is seen that the
50% drug-polymer composites have shown longer drug
release rates than the other composites. Thus, drug re-
lease depends upon the nature of the polymer matrix as
well as pH of the media. This suggests that the drugs in
the blend can be used to be suitable for the basic envi-
ronment of the large intestine, colon, and rectal mucosa
for which there are different emptying times.
Interestingly, more than 90 wt% curcumin is released
from composites at pH 7.4 within 14 hours, whereas less
than 80 wt% of the drug is released at pH 1.2 within 14
hours. This suggests that the drugs in the composites can
be used to be suitable for the basic environment. Further
the electrostatic interaction of composites is more easily
broken at pH 7.4 than at pH 1.2, leading to curcumin
being released more rapidly at pH 7.4 than pH 1.2.
Release data (Figure 6) showed that formulations
containing highest amount of drug (50%) displayed fast
and higher release rates than those formulations contain-
ing a small amount of drug loading. The release rate be-
comes quite slower at the lower amount of drug in the
matrix, due to the availability of more free void spaces
through which a lesser number of drug molecules could
6. Drug Release Kinetics
Drug release kinetics was analyzed by plotting the cu-
mulative release data vs. time by fitting to an exponential
equation of the type as represented below [33].
tM kt
opyright © 2011 SciRes. JBNB
Synthesis and Characterization of Chitosan-Polyvinyl Alcohol Blended with Cloisite 30B for Controlled Release 421
of the Anticancer Drug Curcumin
Figure 3. Schematic representation for cross-linking reaction of chitosan with GA and crosslinking reaction of PVA with GA.
Table 3. Water uptake at pH 7 (1 hour at 37˚C) for different samples.
Sample Water Uptake (U %)
S1 225 ± 20
S1 (GA1) 115 ± 18
S2 261 ± 31
S2 (GA1) 187 ± 21
S3 295 ± 17
S3 (GA1) 230 ± 25
S3 (GA2) 189 ± 16
S3 (GA3) 140 ± 13
S4 330 ± 15
S4 (GA1) 250 ± 21
S5 358 ± 19
S5 (GA1) 308 ± 16
Copyright © 2011 SciRes. JBNB
Synthesis and Characterization of Chitosan-Polyvinyl Alcohol Blended with Cloisite 30B for Controlled Release
of the Anticancer Drug Curcumin
Figure 4. The effect of pH on water uptake for different
crosslinked (GA1 = 2.4 × 10 -5 mol/g polymer) s a m p l e s .
Figure 5. The effect of glutaraldehyde concentrations (GA1
= 2.4, GA2=5, GA3= 7.5) × 10 -5 mol/g polymer) and pH on
water uptake for S3 (Cs/ PVA -50/50) sample.
Here, Mt/M represents the fractional drug release at
time t, k is a constant characteristic of the drug-polymer
system and n is an empirical parameter characterizing the
release mechanism. Using the least squares procedure,
we have estimated the values of n and k for all the five
formulations and these data are given in Table 4. The
values of k and n have shown a dependence on the %
drug loading and polymer content of the matrix. Values
of ‘k’ for composites prepared by varying the amounts of
drug containing and keeping Cs-PVA/C 30B (2.5 wt%)
constant, ranged from 0.04 to 0.26 in pH 7.4 and 0.03 to
0.16 in pH 1.2 respectively. However, the drug-loaded
composites exhibited ‘n’ values ranging from 0.66 to
1.77 in pH 7.4 and 0.61 to 1.69 in pH 1.2 (Table 4), in-
dicating a shift from erosion type release to a swelling
controlled, non-Fickian type mechanism. The values of n
more than 1 have also been recently reported [36,39].
This may be due to a reduction in the regions of low mi-
Figure 6. % Cumulative release Vs. time for different for-
mulation of curcumin loaded in Cs-PVA/C 30B composite
film in (A) pH 7.4 and (B) pH 1.2 media.
cro viscosity inside the matrix and closure of microcavi-
ties during the swollen state of the polymer. Similar
findings have been found elsewhere, wherein the effect
of different polymer ratios on dissolution kinetics was
investigated [40].
7. Conclusions
A number of research workers have reported the use of
chitosan-PVAL for drug delivery for which references
have been cited in the text. A survey of literature reveals
that nobody has used chitosan-PVAL blended with Cloi-
site 30B( a nano particle) as a carrier for controlled re-
lease of curcumin. The blending of PVA and chitosan
(Cs) improves tensile strength and flexibility of blended
films both in dry and wet states. Cross-linking with glu-
taraldehyde improves tensile strength and decreases
elongation of blends. Cross-linking effect of glutaralde-
hyde increases by increasing the Cs content. As the bulk
and surface hydrophilicity of biomaterials are very im-
portant parameter for bioapplication, we studied the ef-
fect of component content, cross-linking and pH on wa-
ter uptake, contact angle and surface tension of different
blended samples. With increasing PVA content in the
blends, water uptake increases. Cross-linking of the
blend with glutaraldehyde decreases water uptake. The
water uptake increases when pH decreased.
opyright © 2011 SciRes. JBNB
Synthesis and Characterization of Chitosan-Polyvinyl Alcohol Blended with Cloisite 30B for Controlled Release 423
of the Anticancer Drug Curcumin
Table 4. Release kinetics parameters of different formulations at pH 7.4 and pH 1.2.
Sample Values of “kValues of “n” Coodination Coefficient, R2
Code pH 7.4 pH 1.2 pH 7.4 pH 1.2 pH 7.4 pH 1.2
1 wt% 0.04 0.03 0.66 0.61 0.9453 0.9056
3 wt% 0.06 0.05 0.79 0.74 0.9621 0.9231
5 wt% 0.08 0.06 1.52 1.31 0.9666 0.9385
7 wt% 0.18 0.12 1.63 1.38 0.9721 0.9714
10 wt% 0.26 0.16 1.77 1.69 0.9756 0.9720
Further we have used different pH medium (i.e. pH
1.2 and pH 7.4) in order to know the release behavior of
drug from polymer matrices at different pH. The effect
of pH on increasing water uptake is more significant for
samples with more Cs content and the effect of pH on
water uptake decreases when glutaraldehyde concentra-
tion is raised. It seems likely that pH has more effect to
increase water uptake for Cs in comparison with PVA.
Water uptake in PVA-chitosann blend films can be con-
trolled by variation of their contents, cross-linking agent
and the pH of solution. It seems likely that, the blended
films are homogeneous on both sides. Blending the PVA
with Cs improves tensile strength, flexibility, bulk and
surface hydrophilicity of the blended films.
The drug release was monitored by changing time, %
drug loading and pH of the medium. It was observed that
the release was much more pronounced in the basic me-
dium than the acidic medium. The kinetics of the drug
release was investigated and based on the kinetic pa-
rameters such as “k” and “n” values the probable drug
release (non-Fickian type of mechanism) has been re-
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