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Int J Pharm Biomed Res 2013, 4(1), 27-33
Research article
International Journal of
PHARMACEUTICAL
AND BIOMEDICAL
RESEARCH
ISSN No: 0976-0350
Design and development of mucoadhesive buccal tablet of labetalol
hydrochloride
Jasvir Singh 1 *, Kanu Saini 2
1 School of Pharmaceutical Sciences, Shoolini University, Solan (HP), Oachghat -173 212, India
2 Amar Saheed Baba Ajit Singh Jujhar Singh Memorial College of Pharmacy, Bela-Ropar, Punjab-140 111, India
Received: 25 Dec 2012 / Revised: 10 Jan 2013 / Accepted: 15 Jan 2013 / Online publication: 15 Feb 2013
ABSTRACT
The aim of the present study is to design and development of mucoadhesive buccal tablets of labetalol hydrochloride.
Since the drug has only 25% oral bioavailability, an attempt was made to develop mucoadhesive buccal tablets of labetalol
hydrochloride to improve the bioavailability and therefore to reduce the frequency of administration. Tablets were prepared
by direct compression method using Carbopol 934P, HPMC K4M as primary polymer and chitosan as secondary polymer in
different drug: polymer ratio. The tablets were evaluated for hardness, weight variation, thickness, percentage drug content,
surface pH, drug-excipients interaction (FTIR). In-vitro studies like swelling index, mucoadhesive strength, and drug release
were performed. Swelling index was increased with increase with increase in polymer concentration. The in-vitro studies
were carried out at phosphate buffer 6.8 at 37±0.5ºC. The best formulation was selected based on the in vitro drug release
profile. The tablet containing drug polymer ratio 1:1.8:1.8 (drug: chitosan: HPMCK4M) was selected as best formulation
which shows the drug release of 92% after 8h and has bioadhesion strength 12.2g. From the present investigation it may be
concluded that the potential mucoadhesive buccal tablets of labetalol hydrochloride could be prepared by direct compression
method, using chitosan and HPMC K4M as a carrier.
Key words: Carbopol 934P, HPMC K4M, Chitosan, In-vitro release studies, Release kinetics.
1. INTRODUCTION
Amongst the various routes of drug delivery, the oral
route is most preferred to the patient and the clinician alike.
However, oral administration of drugs has Disadvantages
such as hepatic first pass metabolism and enzymatic
degradation within the gastro intestinal (GIT), that prohibit
oral administration of certain classes of drugs especially
peptides and proteins. Transmucosal routes of drug delivery
(mucosal linings of nasal, rectal, Vaginal, ocular and oral
cavity) offers distinct advantages over oral administration for
Systemic drug delivery. These advantages include possible
bypass of first pass effect, Avoidances of pre-systemic
elimination within GIT and better enzymatic flora for drug
*Corresponding Author. Tel: +91 9023041520 Fax:
Email: saini.jassi666@gmail.com
©2013 PharmSciDirect Publications. All rights reserved.
absorption. In buccal drug delivery, the buccal mucosa is the
preferred region as compared to the sublingual mucosa. One
of the reasons is that buccal mucosa is less permeable and is
thus not able to elicit a rapid onset of absorption and hence
better suited for formulations that are intended for sustained
release action [1-4].
Within the oral mucosal cavity, the buccal region offers
an attractive route of administration for controlled systemic
drug delivery. Buccal delivery is the administration of drugs
through the mucosal membrane lining the cheeks [5].
Labetalol hydrochloride is an adrenergic antagonist capable
of blocking both alpha and beta receptor, used in the
treatment of hypertension. Labetalol was selected as a model
drug for investigation because of its suitable properties like
half-life 4-6h optimum Labetalol Hydrochloride is rapidly
absorbed following an oral dose but undergoes extensive first
pass metabolism, resulting in only 25% oral bioavailability.
The half-life of labetalol hydrochloride is approximately
4-6h. Hence, the aim was to prepare a mucoadhesive tablet of

Jasvir Singh and Kanu Saini, Int J Pharm Biomed Res 2013, 4(1), 27-33 28
labetalol hydrochloride to ensure satisfactory drug release in
oral cavity with the use of optimum polymer and thereby to
avoid first pass metabolism and prolong duration of action.
So, that it can retain in oral cavity for desired duration and
localize the dosage form in a specific region and control the
release rate of drug.
In the present study, the mucoadhesive buccal tablets of
labetalol hydrochloride were formulated using the polymers
chitosan, carbopol-934 and HPMC K4M.
2. MATERIALS AND METHODS
2.1. Materials
Labetalol hydrochloride was gift sample from Samarth
Pharma, Chitoan from S.D. Fine Chemicals, Mumbai, HPMC
K4M from Colorcon Asia Pvt. Ltd, Carbopol-934P
Qualikems Fine Chemicals Pvt. Ltd.
2.2. Formulation of mucoadhesive tablets [6]
Mucoadhesive tablets of labetalol hydrochloride were
prepared by direct compression technique using different
grades of polymer with varying concentrations (Table 1). The
tablets were prepared using Carbopol 934P, HPMC-K4M as
primary polymers and Chitosan used as secondary polymer as
a penetration enhancer [5-6]. The effect of secondary
polymer on drug release mucoadhesion was studied. The
tablets were compressed using 8mm flat faced punch on a
single stroke punching machine [7-8].
Table 1
Composition of labetalol hydrochloride buccoadhesive tablets
Ingredients (mg) F1 F2 F3 F4 F5 F6 F7 F8
Labetalol hydrochloride 50 50 50 50 50 50 50 50
Chitosan 90 60 120 90 60 120 90 60
Carbopol 934 90 120 60 - - - - -
HPMC K4M - - - 90 120 60 - -
Mgnesium stearate 01 01 01 01 01 01 01 01
Lactose qs qs qs qs qs qs qs qs
2.3. Pre-compression evaluation
The formulated blends were examined for their physical
parameters such as bulk density, tapped density, Hausner’s
ratio, compressibility index and angle of repose (Table 2).
2.4. Post-compression evaluation
The tablets from different formulation (F1 to F8) were
subjected to following tests:
2.4.1. Hardness [7]
Tablets were evaluated for their hardness using Monsanto
hardness tester.
2.4.2. Weight variation
Ten tablets from each formulation were weighed using an
electronic digital balance and the average weight was
calculated. The results are shown in Table 3.
2.4.3. Thickness
Tablets were evaluated for their thickness using slide
calipers. The results are shown in Table 3.
2.4.4. Friability
Friability of the tablets was determined using Roche
friabilator. This device subjects the tablets to the combined
effect of abrasions and shock in a plastic chamber revolving
at 25rpm and dropping the tablets at a height of 6 inch in
each revolution. Pre-weighed sample of tablets was placed in
the friabilator and were subjected to 100 revolutions. Tablets
were de dusted using a soft muslin cloth and reweighed. The
friability (F %) is given by the formula:
% 1
100
where, W 0 is weight of the tablets before the test and W is the
weight of the tablets after test
2.4.5. Drug content [8]
Three tablets from each batch were taken in separate
100mL volumetric flaks containing 100mL of pH 6.8
phosphate buffer and were kept for 24h under constant
stirring. The solutions were then filtered, diluted suitably and
analyzed at 302nm using UV-spectrophotometer. The
average of three tablets was taken as the content of drug in
one tablet unit.
2.4.6. Surface pH [9]
The surface pH of the buccal tablets was determined in
order to investigate the possibility of any in-vivo side effects.
An acidic or alkaline pH may cause irritation to the buccal
mucosa. The method developed by Battenberg et al was used.
A combined glass electrode was used for this purpose. The
tablets were allowed to swell by keeping it in contact with
distilled water (pH 6.5 ± 0.05) for 2h at room temperature.
The pH was measured by bringing the electrode in contact
with the surface of the tablet and allowing it to equilibrate for
1min. The results are shown in Table 4.

Jasvir Singh and Kanu Saini, Int J Pharm Biomed Res 2013, 4(1), 27-33
29
Table 2
Evaluation parameter of pre-compression blend
Formulation code Bulk density (g/mL)
F1
0.434±0.04
F2
0.440±0.08
F3
0.431±.02
F4
0.437±0.07
F5
0.442±0.09
F6
0.427±0.01
F7
0.446±0.08
F8
0.434±0.02
Tapped density (g/mL)
0.490±0.100
0.518±0.03
0.498±0.13
0.526±0.08
0.549±0.111
0.495±0.17
0.515±0.055
0.537±0.100
Compressibility index (%) Hausner’s ratio
11.42±2.1
1.129±0.04
15.05±1.9
1.177±0.02
13.45±0.6
1.155±0.02
16.92±1.6
1.20± ±0.40
19.48±0.63
1.24± ±0.031
13.73±0.43
1.159±0.47
13.39±1.4
1.54± ±0.21
19.18±1.3
1.23± ±0.45
Angle of repose (º)
30.11±3.1º
29.68±2.3º
30.96±1.6º
28.36±1.2º
33.42±2.1º
33.02±2.5º
31.42±1.0 º
31.79±1.4º
Table 3
Evaluation parameter of post-compression tablet
Formulation
code
F1 F2 F3 F4 F5 F6 F7 F8 Weight variation
(mg)
503±5.2
500±10.9
502±4.4
500±4.5
504±7.1
501±3.3
500±4.7
504±2.6
Hardness
(kg/cm2 )
4.4±0.3
4.4±0.2
4.5±0.4
5.0±0.3
4.5±0.34
4.0±0.1
4.0±0.2
5.0±0.2
Friability
(%)
0.455±0.12 0.425±0.3 0.575±0.2 0.40±0.27 0.60±0.07 0.42±0.52 0.61±0.42 0.62±0.71 Thickness
(mm)
4.24± ±0.005
4.24± ±0.01
4.24± ±.005
4.24± ±0.04
4.24± ±.005
4.24± ±.005
4.24± ±0.01
4.24± ±0.01
Table 4
Evaluation parameters of mucoadhesive strengths and surface pH
Formulation code
F1
F2
F3
F4
F5
F6
F7
F8
(n=3, Mean ±SD)
Mucoadhesive strength (g)
12.77±0.5
14.28±0.35
11.45±0.28
12.2±0. .39
11.43±0.33
8.65±0. .31
8.08±0. .40
7.50±0. .45
Surface pH
6.5±0.15
6.4±0.99
6.5±0.15
6.5±0.11
6.5±0.17
6.5±0.09
6.5±0.17
6.6±0.20
% Swelling index
300
250
200
150
100
50
0
0 2 4 6 8
Time (h)
Fig.1. Percentage swelling index of buccal tablets versus time
F1
F2
F3
F4
F5
F6
F7
F8
10
2. .4.7. In-vitro swelling studies [10]
The degreee of swelling of bio‐adhesive polymers
is an
important factor affecting adhesive. For conducting the
study,
a tablet was weighed and placed in a petri‐dish containing
5mL of phosphate buffer at pH 6.8 for 12h, the tablets were
taken out from
the petri‐dish
and excess water was removed
carefully by using filter paper. The swelling index was
calculated using the following formula and results are shown
in
Fig.1.
Fig.2. Bioadhesion testing instrument
% Swelling index Wet w eight Dry weight 100
Wet weight
2. .4.8. In vitro mucoadhesivee study
The tensilee strength required to detach the polymeric
patch from the mucosal surface was applied as measuree of the
bioadhesive performance.
Instrument: The apparatus was locally assembled and
was a
modification of the physical balance apparatus (Fig.2). The
device was mainly composed
of a two-arm
balance. The left
arm
of the balance was replaced by the petri-dish vertically
suspended through a 3 threads. At the same side, the buccal
mucosa of goat is attached to both petri-dishes.
Method: The fabricated balance described above was used for
the
bioadhesion
studies. The goat buccal mucosa, excised and
washed
was fixed to the movable
platform. The
mucoadhesive
tablet was fixed to petri-dish by using
‘cyanoacrylate’
as adhesive. The exposed
tablet surface was
moistened with 1mL of isotonic phosphate buffer for 30sec
for
initial hydration and swelling. The platform was
then

Jasvir Singh and Kanu Saini, Int J Pharm Biomed Res 2013, 4(1), 27-33 30
Table 5
In vitro release of labetalol hydrochloride buccal tablet
Time
Formulation code
F1 F2 F3 F4 F5 F6 F7 F8
0.5h 2.9±0.2 1.7±0.8 2.2±0.6 3.5±1.7 3.8±1.3 2.9±1.2 5.7±1.6 3.0±0.9
1h 4.5±0.3 5.9±1.7 4.8±1.6 16.2±1.8 12.6±2.2 6.7±1.6 8.0±3.4 11.2±4.3
2h 14.1±0.4 10.9±2.4 13.7±3.9 31.5±1.2 25.3±3.8 14.4±1.2 29.3±0.8 28.4±2.4
3h 25.1±1.1 15.6±1.7 22.0±5.8 53.8±4.6 35.8±4.0 23.3±2.1 53.8±4.1 49.2±3.1
4h 31.4±0.6 24.6±2.9 34.2±4.8 60.7±5.6 39.8±5.0 33.1±2.3 71.2±2.7 68.4±0.3
5h 45.9±3.1 29.3±1.8 43.5±5.3 69.3±3.1 47.7±3.8 39.9±2.3 73.6±1.6 70.3±1.5
6h 54.6±1.0 35.5±3.6 53.6±4.9 76.4±3.4 59.4±0.7 52.7±3.6 63.7±1.9 75.7±1.6
7h 60.9±1.4 42.5±1.9 62.9±2.3 84.2±1.4 71.4±0.3 63.7±1.9 Discarded due to release of drug
8h 67.6±1.2 50.3±2.1 70.8±0.9 92.1±0.8 81.5±0.7 75.7±1.6 before time
Table 6
Effect of storage condition on optimized tablet (F4)
Days Weight (mg) Surface pH Mucoadhesive
strength (g)
% Drug
content
0 505.50 6.5 12.2 97.08
30 505.47 6.4 12.1 97.05
60 505.42 6.4 12.0 97.03
90 505.30 6.3 12.0 97.0
powders were mixed separately with IR grade KBr and
pellets were prepared by applying a pressure of 10 tons in a
hydraulic press. The pellets were scanned over a wavelength
range of 400 to 4000cm ‐1 using an FTIR instrument.
Drug‐excipients interactions play a vital role in the release of
drug from formulations. FTIR techniques have been used to
study the physical and chemical interactions between drug
and excipients used.
% Cumulative drug release
100
90
80
70
60
50
40
30
20
10
0
% CDR (o day)
%CDR (90 days)
0 2 4 6 8 10
Time (h)
Fig.3. Comparison of drug release before and after storage
2.4.10. In-vitro release studies [12]
Various apparatus has been designed to study dissolution
rate and in vitro release rate profile of drug from bioadhesive
drug delivery systems and tablets. The study was carried out
in USP II apparatus, employed paddle stirrer at 50rpm and
900mL of phosphate buffer pH 6.8 as dissolution medium
maintained at 37±0.5°C. The tablets were supposed to release
drug from one side only hence a one side of tablets was fixed
a glass disk with cyanoacrylate adhesive. The disk was
placed at the bottom of dissolution vessel. An aliquots of
5mL was withdrawn at 0.5, 1, 2, 3, 4, 5, 6, 7 and 8 th h and
replaced with fresh medium. The samples were filtered and
analyzed it at 302nm using UV-Visible spectroscopy and the
results were summarized as in Table 5.
raised upward until the hydrated patch was brought into the
contact with the mucosal surface. A preload of 20g was
placed over the petri-dish surface for 3min as initial pressure
to attach the buccal mucosa with tablet. And then weights
were slowly increased on the right pan, till the patch detaches
from the mucosal membrane. The weight required to detach
the patch from the mucosa give the bioadhesive strength of
the mucoadhesive patch. The procedure is repeated for 3
times for each patch and mean value of the 3-trials was taken
for each set of formulation. After each measurement the
tissue was gently and thoroughly washed with isotonic
phosphate buffer and left for 5min before taking reading.
2.4.9. Interaction studies [11]
The pure drug, labetalol hydrochloride and its mixture
with the polymer Chitosan, HPMC K4M and Carbopol 934P
2.4.11. Stability studies [13]
Most recently a guideline issued by the International
Conference on Harmonization (ICH, 1993) indicates that the
purpose of stability testing is to provide evidence on how the
quality of a drug substance or the drug product varies with
time under the influence of variety of environmental factors,
such as temperature, humidity and light, and enables
recommended storage conditions, retest periods, to be
established.
Short term stability studies were performed at a
temperature o of 40±2°C/75±5%RH over a period of 3 month
(90 days) on the promising buccal tablet of labetalol
hydrochloride. Sufficient number of tablets (15) were packed
in amber coloured rubber stopper vials and kept in stability
chamber maintained at 40±2°C/75±5%RH. At intervals of 1
month, the tablets were visually examined for any physical
changes, changes in weight, surface pH, mucoadhesive

Jasvir Singh and Kanu Saini, Int J Pharm Biomed Res 2013, 4(1), 27-33 31
80.8
75
70
65
60
2526.67
946.08
1011.32
900.81
1148.08
1120.81
1035.64
1323.37
1310.97
1212.36
753.00
666.88
521.28
453.31
%T
55
50
45
2752.08
2805.43
2980.97
3029.12
3066.16
1602.56
1580.99
1389.78
1499.33
1437.93
1641.35
1415.56
1251.83
1268.11
1063.48
824.59
698.10
588.32
40
3355.00
35
3189.57
1674.40
30.0
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400.0
cm-1
Fig.4. Observed spectra of labetalol hydrochloride
70.4
, g
65
%T
60
55
50
45
40
35
2752.29
2858.52
2807.29
3029.06
2981.13
3087.60
3066.06
522.22
452.53
945.54
900.07
1148.09
752.92
1211.96
666.90
1323.32 1120.28
1311.11 1105.67
1034.97
698.44 588.64
825.42
1602.29
1063.29
1581.01
1251.59
1268.08
1499.21
1438.37
1389.49
1641.21 1415.67
3354.85
30
3189.71
25.0
1674.28
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400.0
cm-1
Fig.5. IR Spectra of mixture of labetalol hydrochloride + Chitosan
77.5
76
, g
74
72
70
909.01
723.08
751.98
516.24
453.54
68
946.21
668.48
%T
66
64
62
2944.05
1602.85
1581.00
1323.67
1311.21 1148.25
1212.14
1120.99
1035.35
825.46
697.86
588.06
60
58
1641.26
1499.28
1251.56
1437.55 1268.28
1389.54
1063.27
56
1415.57
54
52
3355.66
50
3190.10
1674.45
48.0
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400.0
cm-1
Fig.6. IR Spectra of mixture of labetalol hydrochloride + HPMC K4M
81.7
80
78
76
74
72
70
1581.05
1499.31
1310.35
944.28
904.97
1119.49
1034.82
1062.50
519.82
452.90
753.64
665.90
698.49
589.12
%T
68
66
1389.49
1211.00
823.59
64
62
3354.76
2951.51
1641.71
1710.17
1438.90
1415.34
1266.64
60
58
3189.46
56
1674.90
55.0
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400.0
cm-1
Fig.7. IR Spectra of mixture of labetalol hydrochloride + Carbopol 934

Jasvir Singh and Kanu Saini, Int J Pharm Biomed Res 2013, 4(1), 27-33 32
strength and drug content and at the end of 3 month period
(Table 6); they were also tested for in vitro drug release
pattern (Fig.3).
3. RESULT AND DISCUSSION
In the present project buccal tablets of labetalol
hydrochloride were prepared and evaluated for achievement
of extend release action of active moiety. The tablets were
prepared by direct compression method using varying
concentration of polymers. These prepared tablets were
evaluated for their various quality control parameters.
The pure drug was confirmed by chemical test as
prescribed in IP (2007). The melting point of obtained sample
was found to be 195 o C. The IR Spectra of obtained sample
drug was concordant with reference spectra as given in IP
(2007). Their important chromospheres groups elucidated the
IR Spectra. The various peaks were depicted in Fig.4-Fig.7.
The IR Spectra verified the authenticity of the obtained
sample.
The solubility of labetalol hydrochloride was determined
in phosphate buffer. The solubility was found in phosphate
buffer (pH 6.8) was 80±0.57μg/mL. The IR Spectra of the
various mixtures reveal all the peak of the drug. No
significant shifts in the peaks corresponding to the drug were
observed on the mixing. Hence the drug and polymers can be
successfully incorporated in the design of buccal tablets.
The formulated blends and prepared tablets were
examined for their physical properties. The various
parameters were evaluated such as bulk density, tapped
density, Hausner’s ratio, compressibility index and angle of
repose. After compression of blend, the tablets were
evaluated for their physical organoleptic properties (colour,
odour, taste) and quality control parameter (thickness,
hardness and friability). All the formulations were white in
colour, odourless, flat in shape with smooth surface without
any defects. The prepared tablets were elegant and having lot
to lot tablet uniformity and also frees from any surface
texture problems.
The bulk density of mixed blend varied between
0.427±0.01 to 0.442±0.09g/mL. The results indicate good
packaging capacity of tablets. The tapped density was found
in the range of 0.490±0.10 to 0.549±0.11mg/mL. The
compressibility index was found in between 11.42±2.1 to
19.48±0.11. The angle of repose was found to be 28.36±1.2
to 33.42±2.12°. The results for characterization of blend of
buccal tablets labetalol hydrochloride tablets were shown in
Table 2. This result indicates the good flow property of the
mixed blend.
The hardness of prepared mucoadhesive buccal tablets
was from 4.0±0.1 to 5.0±0.3kg/cm 2 . The thickness of the
tablets was found 4.24±0.1 to 4.24±0.4mm. All prepared
tablets complies the Indian Pharmacopoeia standard for
weight variation and friability. The drug content was from
90±0.1to 97.2±0.4% suggested uniform mixing of drug. The
surface pH for all the buccal tablets was from 6.4 to 6.6
which was near to salivary pH (6.5-7.5) suggesting that the
prepared buccal tablets can used without the risk of mucosal
irritation and discomfort.
The swelling study of prepared buccal tablets was
performed in phosphate buffer pH 6.8 and the results are
prepared as percentage weight change with respect to time in
Table 3. The swelling of all the tablets was increased as the
time proceeds because the polymers gradually absorb water
due to hydrophilicity to the polymer. After 8h the swelling
index of the different formulations was within the range of
160.3 to 243.9%. The chitosan is insoluble in aqueous media
of pH 6.8 but absorb large quantity of water and hence
formulation of gel. The swelling was getting affected in the
formulation containing secondary polymer chitosan. The
percent swelling index determined at 0.5, 1, 2, 3, 4, 5, 6, 7
and 8h and it was increased with an increase polymer
concentration with respect to time. The general trend
suggested an increase in percent swelling index with an
increase in the hydrophilic polymer. Chitosan-Carbopol 934P
buccal tablets showed the greatest swelling (F3 – 51.4% in
1h) followed by (Fig.2).
In vitro drug release experiments were performed at
37±1 o C in U.S.P II dissolution apparatus. The results showed
that all the formulations release the drug within 0.5 to 8h.
The maximum drug release was found in formulation F4
(92.1±1.2 %) within 8h. The order of drug release was found
to be: F4>F5 >F6 >F7 >F3 >F8>F1>F2. Formulations F1,
F2, F3 which contain Chitosan-Carbopol 934P in varying
concentration and the release were found to be after the 8h
67.6, 50.3, and 75.8% respectively. The drug release was
found to be 92.1, 81.5 and 75.7% respectively for the
formulations F4, F5, F6. The formulation F7 and F8 were
discarded because they release the drug before time.
The strength of the formulation (tablet) was depends on
the property of mucoadhesive polymers, which adhere to the
mucosal surface and also the concentration of polymers used.
The highest bond strength was possessed by the formulation
F2 containing Chitosan and Carbopol 934P in the ratio of 1:2.
Decrease the content of the Carbopol 934P resulted in
decreased adhesion force. Table 4 deposits the mean values
of in-vitro bioadhesivity (g) of the polymeric tablets. The
bioadhesivity increased with an increase in hydrophilic
polymers.
The obtained release data were subjected for the kinetic
treatment to know the type and order of drug release. The invitro
release data was subjected to zero order, first order,
Higuchi and Korsemeyer-Peppas model in order to establish
the drug release mechanism and kinetics of drug release from
the buccal tablets. The regression analysis which correlation
coefficient ‘r 2 ’ values for different kinetic model is
summarized in Table 7. When the data was subjected to zero
order and first order kinetic model, a linear relationship was
observed with high ‘r 2 ’ value for zero order as compared to
first order model suggested that the formulation was zero
order controlled release. Higuchi’s model was applied to the
in vitro release data, linearity was obtained with high

Jasvir Singh and Kanu Saini, Int J Pharm Biomed Res 2013, 4(1), 27-33 33
Table 7
Release kinetics studies
Formulation Zero order First order Higuchi Korsmeyer-Peppas
code
r 2 r 2 r 2 r 2 n
F1 0.985 0.946 0.877 0.991 0.852
F2 0.990 0.974 0.869 0.992 0.912
F3 0.993 0.959 0.898 0.994 0.819
F4 0.923 0.976 0.898 0.962 0.951
F5 0.979 0.969 0.876 0.988 0.866
F6 0.984 0.909 0.881 0.993 0.907
F7 0.952 0.908 0.868 0.954 0.835
F8 0.965 0.922 0.874 0.954 0.821
‘r 2 ’ value suggested that the drug release from tablet follow
diffusion mechanism as all the polymer used were gel based
matrix type. Korsemeyer-Peppas model was applied which
will define exact release mechanism when more than one
type of release phenomenon was observed. Good linearity
with high ‘r 2 ’ value was observed with Korsemeyer-Peppas
model. The values of release exponent ‘n’ calculated as a
slope define the release mechanism. The value of ‘n’
obtained for all the tablets formulation was ˃0.5 and˂1.0
suggested that the drug release followed non- fickian
anomalous dissolution due to higher affinity of hydrophilic
polymers towards water.
4. CONCLUSIONS
From the present investigation it may be concluded that
the potential mucoadhesive buccal tablets of labetalol
hydrochloride could be prepared by direct compression
method, using chitosan and HPMC K4M as a carrier. The
best formulation was selected based on the in vitro drug
release profile. The best formulation, F4 which contains drug
polymer ratio of 1:1.8:1.8 (drug: chitosan: HPMCK4M)
shows the prolonged drug release upto 8h. Further, the best
formulation can be manufactured with consistent
reproducible physical and dissolution characteristics and
compared to that of a reputed marketed product. Further
pharmacodynamic and pharmacokinetic studies should be
carried out for the best formulation and compared with the
marketed product.
ACKNOWLEDGMENT
Authors wish to give thanks to School of Pharmaceutical
Sciences, Shoolini University, Solan, and authority for
providing suitable research laboratory to carry out this project
work and also my deep greatness to Samarth Pharma,
Nalagarh, India, for providing gift sample of labetalol
hydrochloride.
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