FORMULATION AND IN-VITRO EVALUATION OF … was a gift sample from CADILA Pharmaceuticals Pvt. Ltd....

Vol-3, Issue-4, Suppl-1, Nov 2012 ISSN: 0976-7908 Patel et al

www.pharmasm.com IC Value – 4.01 2532

PHARMA SCIENCE MONITOR

AN INTERNATIONAL JOURNAL OF PHARMACEUTICAL SCIENCES

FORMULATION AND IN-VITRO EVALUATION OF MUCOADHESIVE

BUCCAL TABLET OF DOMPERIDONE

Rahul B. Patel *, K. R. Patel, M. R. Patel, N. M. Patel

Shri B. M. Shah College of Pharmaceutical Education & Research, College Campus, Dhansura Road, Modasa, Dist. Sabarkantha, 383350, Gujarat, India.

ABSTRACT The object of this research work is to design efficacious and prolonged release buccal tablet of Domperidone. It is Anti-emetic agent. It has very low bioavailability 15%. It undergoes first pass metabolism that lowering bioavailability. Direct access to the systemic circulation bypasses drug from the hepatic first pass metabolism, leading to high bioavailability. Moreover, the buccal route is easily accessible, has a good patient compliance and can be used in patients who can’t swallow. Bilayer buccal tablet was prepared by using mucoadhesive polymers combination of HPMC K4M and Carbopol 934P, by direct compression method using HP-β-CD as solubility enhancer and ethyl cellulose as backing layer. The formulation was optimized by 32 full factorial statistical designs by selecting independent variables, Ratio of polymer as factor X1 and Concentration of polymer as factor X2. The prepared formulations were evaluated for various evaluation studies. Statistical analysis as well as kinetic studies performed. Statistical study showed that both factors X1 and X2 had significant effect on dependable variables Q8 (P=0.000), Mucoadhesive strength (P=0.000) and Swelling index (P=0.00).By using HP-β-CD with drug in complex formation enhance the solubility of drug, as well as dissolution of tablet, Formulation D1 was selected as an optimum formulation as it shows more similarity in dissolution profile with theoretical profile (f2 = 72.43 and f1 = 1.24). The optimized formulation D1 had given release of 92.28% after 8hrs and it had optimum swelling, mucoadhesive property and permeation from buccal mucosa. It also had desired drug release kinetic and found to be stable for the period of 1 month. Keywords: HydroxyPropyl-β-Cyclodextrine, HPMC K4M, Carbopol 934P, Ethyl cellulose, 32 factorial designs. INTRODUCTION

The buccal region of the oral cavity is an attractive target for administration of the drug

of choice, particularly in overcoming deficiencies associated with the latter mode of

administration. Problems such as high first-pass metabolism and drug degradation in the

gastrointestinal environment can be circumvented by administering the drug via the

buccal route. Moreover, rapid onset of action can be achieved relative to the oral route

and the formulation can be removed if therapy is required to be discontinued. It is also



possible to administer drugs to patients who unconscious and less co-operative. To

prevent accidental swallowing of drugs adhesive mucosal dosage forms were suggested

for oral delivery, which included adhesive tablets, adhesive gels, adhesive patches and

many other dosage forms with various combinations of polymers, absorption enhancers.

In addition to this, studies have been conducted on the development of controlled or slow

release delivery systems for systemic and local therapy of diseases in the oral cavity. [1]

Domperidone is a dopamine receptor (D2) antagonist. It is used as an antiemetic agent for

short-term treatment of nausea and vomiting of various etiologies. It is also used for its

prokinetic actions. It is rational to formulate the mucoadhesive dosage form of

Domperidone as it is known to have a low oral bioavailability due to extensive first-pass

effect. Sudden death may occur when Domperidone is administered intravenously in high

doses. The plasma half-life of Domperidone is 7 hrs. It has a low molecular weight

(425.92) and no objectionable taste. These make it an appropriate candidate for being

incorporated into the mucoadhesive formulation. [2-3] Systematic optimization techniques

have frequently been employed for the design and development of pharmaceutical dosage

forms. Embodying the use of appropriate experimental designs, generation of polynomial

relationships and optimum search methods, generally using pertinent software. Factorial

designs (FDs), where all the factors are studied in all possible combinations, are

considered to be the most efficient in estimating the influence of individual variables

(main effects) and their interactions using minimum experimentation. An FD for two

factors at three levels each (32) is considered. Identical to a two-factor composite design.

The aim current study was to develop and optimize the mucoadhesive buccal tablet of

Domperidone for buccal delivery. A computer-aided optimization process using a 32 FD

was employed to investigate the effect of two independent variables, i.e. ratio of polymer

(Carbopol 934P: HPMC K4M) (X1) and concentration of polymers (Carbopol and HPMC

K4M) (X2). [4]

MATERIAL AND METHOD

Materials

Domperidone was a gift sample from CADILA Pharmaceuticals Pvt. Ltd. (Ahmadabad,

India), HP-β-CD from Triveni interchem pvt. Ltd., Methocel K4M and ethyl cellulose by



Colorcon Asia Pvt. Ltd. (Goa, India), Carbopol 934P from M/s Lobe Chemie Ltd.

(Mumbai, India) and lactose and magnesium stearate from ACME Chemicals. Were

procured from commercial sources. All other chemicals used in the study were of

analytical grade.

Compatibility study [5]

This study has been done to check whether there is any compatibility related problems

are associated with drug and excipients used for the formulation of tablet. The drug and

excipients must be compatible with one another to produce a product that is stable,

efficacious, attractive and easy to administer and safe. If the excipients are new and not

been used in formulations containing the active substance, the compatibility studies are of

paramount importance. The IR spectral analysis of a drug and other excipients were taken

using Press pellet technique (using KBr). The IR spectra’s were determined by using

Shimadzu FTIR 8400 S. All the spectra were recorded in the range of 400‐4000 cm‐1.

Differential Scanning Calorimeter (DSC)

Thermo grams were obtained by using differential scanning calorimeter at a heating rate

20°C/min over a temperature range of 50-300°C by using instrument Differential

Scanning Calorimeter. The sample was hermetically sealed in an aluminum crucible.

Thermo grams of drug and formulation were compared for any disappearance or shifting

in characteristic peak of drug melting point.

Formulation of Inclusion Complex

Preparation of Physical mixture (PM):

Equimolar physical mixtures were prepared by blending exact weighed amounts of

drug and HP-β-CD until homogenous mixture is obtained.

Preparation of inclusion complex by kneading method (KM):

In this method the equimolar physical mixture (1:1) was prepared as discussed above and

then slowly 1.5 times of water to the total weight of physical mixture was added slowly

during continuous kneading. The mixture is kneaded for about 1 hour to get the paste.

Then this paste was allowed to dry at room temperature for 24 hour and then the dried

powder sieved to get uniform particle size distribution.

In vitro dissolution study of prepared inclusion complex:



In vitro dissolution study of inclusion complex was conducted using USP dissolution

apparatus II at 50 rpm, using 500 ml phosphate buffer pH 6.8 as a dissolution media

maintaining at 37 ± 0.50 C. Quantity of inclusion complex equivalent to 10 mg of drug

was taken. 5 ml Sample were withdrawn at time intervals of 5, 10, 20, and 30 up to 60

min. and filtered through a 45µm filter paper, diluted and assayed at 284 nm using UV/

Visible double beam spectrometer. The volume of dissolution fluid was adjusted to 500

ml by replacing each 5 ml aliquot withdrawn with 5 ml of phosphate buffer.

Selection of drug: HP-β-CD ratio has been carried out by preparing inclusion complex

of different ratio like 1:1, 1:2, molecular ratio and enhancement of solubility, which is

proved as a best for the improvement of solubility.

Preparation of Bilayer Buccal Tablets:

Buccal tablets were composed of two layers i.e., Core layer and Backing layer, Core layer

contains drug complex made by inclusion complexation, different mucoadhesive

Polymers, Lactose, Talc, Magnesium stearate and Aspartame as a sweetener. This layer

weighed about 100mg. Backing layer contains water impermeable compound, ethyl

cellulose. The weight of this layer was 50 mg. Therefore total weight of the tablet was

150 mg.

Preparation: Direct double compression technique was employed for the formulation. In

this technique, first intermediate layer was formed and blend of second layer was placed

on first intermediate layer and compressed to get bilayer tablet. Compositions of the core

layer contains drug, mucoadhesive polymers.

Pre-Compression Evaluation Parameters[6-7]

Bulk Density:

Weigh accurately 25g of powder, which was previously passed through 20# sieve and

transferred in 100 ml graduated cylinder. Carefully level the granules without

compacting, and read the unsettled apparent volume (V0). Calculate the apparent bulk

density in gm/ml by the following formula

Bulk density (Eq. 2.1)

Tapped bulk density:



Weigh accurately 25 g of granules, which was previously passed through 20# sieve and

transfer in 100ml graduated cylinder. Then mechanically tap the cylinder containing the

sample by raising the cylinder and allowing it to drop under its own weight using

mechanically tapped density tester that provides a fixed drop of 14± 2mm at a nominal

rate of 300 drops per minute. Tap the cylinder for 500 times initially and measure the

tapped volume (V1) to the nearest graduated units, repeat the tapping an additional

750times and measure the tapped volume (V2) to the nearest graduated units. If the

difference between the two volumes is less than 2% then final the volume (V2). Calculate

the tapped bulk density in gm/ml by the following formula:

Tapped Density (Eq. 2.2)

Carr’s Index:

The Compressibility Index of the granules blend was determined by Carr’s

compressibility index. It is a simple test to evaluate the BD and TD of a granules and the

rate at which it packed down. The formula for Carr’s Index is as below:

Carr’s Index (Eq. 2.3)

Hausner’s Ratio:

The Hausner’s ratio is a number that is correlated to the flow ability of a granular

material.

Hausner’s Ratio (Eq. 2.4)



TABLE 1: EFFECT OF CARR’S INDEX AND HAUSNER’S RATIO ON FLOW

PROPERTY

Carr’s Index (%) Flow Character Hausner’s Ratio < 10 Excellent 1.00–1.11 11–15 Good 1.12–1.18 16–20 Fair 1.19–1.25 21–25 Passable 1.26–1.34 26–31 Poor 1.35–1.45 32–37 Very poor 1.46–1.59 >38 Very, very poor >1.60

Angle of repose:

The flow characteristics are measured by angle of repose. Improper flow of powder is

due to frictional forces between the particles. These frictional forces are quantified by

angle of repose. Angle of repose is defined as the maximum angle possible between the

surface of a pile of the powder and the horizontal plane.

(Eq. 2.5

Where,

h = Height of pile.

r = Radius of the base of the pile.

θ = Angle of repose

TABLE 2: EFFECT OF ANGLE OF REPOSE (Θ) ON FLOW PROPERTY

Sr. No. Angle of Repose (θ) Type of Flow 1 < 200 Excellent 2 200-300 Good 3 300-340 Passable 4 >350 Very poor

32 full factorial design

A 32 randomized full factorial design was employed in the present study. In this design 2

factors were evaluated, each at 3 levels, and experimental trials were performed for all 9

possible combinations. The ratio of polymer (Carbopol:HPMC K4M) (X2) and

concentration of polymers Carbopol and HPMC K4M (X2) were chosen as independent

variables in 32 full factorial design, while Q8 (% drug release after 8 hours), swelling



index, Mucoadhesive strength were taken as dependent variables. The composition of

factorial design batches (D1-D9) is shown in Table 4.10 and Table 4.11. The prepared

formulations were evaluated for assay, friability and hardness and in vitro release study.

Statistical treatment was carried out to the factorial design batches using design expert

DX8 stat ease software.

TABLE 3: CODING OF VARIABLE TABLE

Evaluation of Prepared Tablets:[8]

Weight Variation:

Twenty tablets were selected at random, weighed and the average weight was calculated.

Not more than two of the individual weights should deviate from the average weight by

more than 7.5 % as per IP.

TABLE 4: OPTIMIZE FORMULATIONS OF BILAYER BUCCAL TABLET

Coded Values Actual Values

X1 = ratio of polymers (Carbopol : HPMC K4M)

X2 = concentration of polymer (Carbopol and HPMC K4M)

-1 1:2 10% 0 1:1 15% 1 2:1 20%

Ingredients R1 R2 R3 R4 R5 R6 R7 R8 R9

Ingr

edie

nts

(m

g)

Domperidone+HP-β-CD(10mg drug)

37 37 37 37 37 37 37 37 37

Carbopol 934P 3.33 5 6.66 5 7.5 10 6.66 10 13.34

HPMC-K4M 6.66 5 3.33 10 7.5 5 13.34 10 6.66

Lactose 49 49 49 44 44 44 39 39 39

Magnesium Stearate 1 1 1 1 1 1 1 1 1

Talc 1 1 1 1 1 1 1 1 1

Aspartame 2 2 2 2 2 2 2 2 2

Backinglayer:-Ethyl Cellulose

50 50 50 50 50 50 50 50 50

Total weight in mg 150 150 150 150 150 150 150 150 150



Friability:

For each formulation, pre weighed tablet sample (20 tablets) were placed in the Roche

friabilator which is then operated for 100 revolutions. The tablets were deducted and

reweighed. Conventional compressed tablets that loose <1% of their weight are

considered acceptable.

Hardness:

Hardness was measured by using Monsanto hardness tester. For each batch ten tablets

were tested. It is measured in “Kg/ cm2” unit.

Content Uniformity:

Twenty tablets were weighed and powdered in a glass mortar. Quantity of powder

equivalent to 10 mg of Domperidone was accurately weighed and transferred to 100 ml

pH 6.8 phosphate buffers in volumetric flask. From the resulting solution 10 ml of the

sample was withdrawn and adjusted final volume in volumetric flask up to 100 ml using

pH 6.8 phosphate buffers. The solution was analyzed at λmax value of 284 nm by using

UV-Visible spectrophotometer. The content of drug was calculated from calibration

curve.

In Vitro Swelling or Swelling Index:

This test was carried out by using Petri dishes having 10 ml of phosphate buffer of pH 6.8

and tablet was placed in Petri dish. The initial weights of the drug loaded tablets in each

batch were determined (W0) using an electronic balance. Tablets from each batch were

removed at different time intervals (1, 2, 3, 4, 6 and 8 hrs), wiped with filter paper to

remove excess water from the tablet surface, and then reweighed (W1). The swelling

index (% w/w) was determined from the following relationship and plotted against time.

The experiment was performed in triplicate. (Eq.4)

Swelling index (Eq. 2.6)

In Vitro Residence time test:

The in vitro residence time is one of the most important physical parameters of buccal

tablet. A buccal tablet was pressed over the excised goat buccal mucosa for 30 sec after

previously being secured on a glass slide and was immersed in a beaker containing 500



ml of pH 6.8 isotonic phosphate buffer, at 37±0.2°C. One stirrer was fitted at a distance

of 5 cm from the tablet and rotated at 25 rpm. The time for complete erosion or

detachment of the tablet from the mucosa was recorded.

Surface pH measurement:

The buccal tablets were first allowed to swell by keeping them in contact with 5 ml of pH

6.8 phosphate buffer for 2 hrs. The surface pH was then found by bringing a combined

glass electrode near the surface of the tablets and allowing the reading to stabilize for at

least 1 min. The measurements were taken in triplicate for each batch of the buccal tablet.

In Vitro Mucoadhesive strength test:

Figure 1 Modified Mucoadhesive Strength Tester

Mucoadhesive strength of the buccal tablets was measured by using the modified

physical balance. The test assembly was fabricated as shown in schematic presentation

(Figure 1). This method involves the use of goat buccal mucosa as the model mucosal



membrane. The fresh goat buccal mucosa was purchased from slaughter house and it was

then washed in isotonic phosphate buffer pH 6.8. The two sides of the balance were

balanced with a 5 gm weight on the right hand side. A piece of fresh membrane was

glued to a support (glass block) with cyanoacrylate adhesive. The block was then lowered

into the glass container, which was then filled with isotonic phosphate buffer pH 6.8 kept

at 37± 1 °C, such that the buffer just reaches the surface of mucosal membrane, and keeps

it moist. This was then kept below the left hand setup of the balance. The test

mucoadhesive tablet was glued with the same adhesive to a rubber block hanging on the

left hand side and the balance beam raised with the 5 gm weight on the right pan was

removed off the weight. This lowered the rubber block along with the tablet over the

mucosa with a weight of 5 gm. The balance was kept in this position for 3 minutes and

then slowly water was added to the plastic container in the right pan by pipette. The

detachment of two surfaces was obtained. Weight of water was measured. Then the

Mucoadhesive strength of tablet was calculated. Three tablets were tested on each goat

buccal mucosal membrane. After each measurement, the tissues were gently and

thoroughly washed with phosphate buffer pH 6.8 and left for 5 minutes before the next

experiment. Fresh membrane was used for each batch of tablets. The experiment was

performed in triplicate.

In Vitro Dissolution study:

The USP type II rotating paddle method was used to study the drug release from the

bilayer tablet. The dissolution medium consisted of 500 ml of pH 6.8 phosphate buffer.

The release study was performed at 37 ± 0.5°C, with a rotation speed of 50 rpm. The

backing layer of the buccal tablet was attached to the glass slide with cyanoacrylate

adhesive. The disk was placed at the bottom of the dissolution vessel. Aliquots were

withdrawn at regular time intervals and replaced with fresh medium to maintain sink

conditions. The samples were filtered, made appropriate dilutions with phosphate buffer

and were thereafter analyzed spectrophotometrically at λmax value of 272 nm using a

Shimadzu UV-Visible1800 double-beam spectrophotometer. Cumulative percentage drug

release was calculated using an equation obtained from a calibration curve which was



developed in the range of 5-35µg/ml for pH-6.8 phosphate buffer. The experiment was

performed in triplicate.

Ex vivo permeation study

Figure 2 Franz Diffusion Cell

The fresh goat buccal mucosal membrane was obtained from slaughter house. It was than

excised by removing the underlying connective and adipose tissue and was equilibrated at

37 ± 1.0 C for 30 min in pH 6.8 isotonic phosphate buffer. The buccal epithelium was

carefully mounted in between the two compartments of Franz Diffusion Cell. Tablets

were stuck to the mucosa in the donor side containing pH 6.8 phosphate buffers. Receiver

medium was 20 ml of pH 6.8 phosphate buffer maintained at 37 ± 0.5 C under gentle

stirring. From the receiver compartment, 5 ml aliquots were collected at predetermined

time intervals and replaced by an amount of fresh buffer. The samples removed were

filtered, diluted and analyzed at λmax value of 284 nm using a Shimadzu UV-Visible 1800



double-beam spectrophotometer. The schematic representation of Franz diffusion

apparatus was displayed in Figure 2.

KINETIC TREATMENT ON DRUG RELEASE [9]

Different mathematical models may be applied for describing the kinetic of the drug

release process from the formulation matrix; the most suited being the one which best fits

the experimental results. The kinetic of Domperidone release from tablets was

determined by finding the best fit of the dissolution data (drug release Vs time) to distinct

models: Zero order [eq.2.7], first‐order [eq.2.8], Higuchi [eq. 2.9], and Korsmeyer-

peppas model [eq. 2.10].

Qt = k0 t………. (Eq. 2.7)

Qt = Q∞ (1‐e–k1t)………. (Eq. 2.8)

Qt = kH t1/2………. (Eq. 2.9)

Qt/Q∞ = kKPtn………. (Eq. 2.10)

Where,

k0 = Zero order rate constant expressed as concentration/time & t is the time.

k1 = First order constant.

kH = Constant reflecting the design variables of the system.

Qt = Amount of drug released in time t.

Q0 = Initial amount of drug in tablet.

Qt/Q∞ = Fraction of drug release.

kKP = Release rate constant.

n = Diffusion release exponent indicative of the drug release mechanism

Accelerated Stability Study[10]

Stability testing of drug products begins as a part of drug discovery and ends with demise

of compound or commercial product. FDA and ICH specifies the guidelines for stability

testing of new drug products, as a technical requirement for registration of

pharmaceuticals for human use (ICH Q1C Guidelines).

The samples of optimized batch were kept at 40˚C temperature and 75% RH (Relative

Humidity) for one month in HDPE bottle. Then samples were withdrawn and analyzed

for physical evaluation and in-vitro dissolution study.



RESULTS & DISCUSSION

Interference Study:

FT-IR Spectroscopy:

Overlapping of IR spectra indicate no significant difference in characteristic peak at wave

numbers of the drug in presence of the excipients given in figure 3 & table5.

50075012501750250035001/cm

-50

0

50

100

150

%T

3099.7

1

17

16.7

01695.4

9 1545.0

31490.0

6

1341.5

4

1246.0

6

11

47.6

8

832.3

1732.0

1 664.5

0

3023.5

23017.7

32941.5

42819.0

6

2138.1

6

1705.1

31688.7

316

29.9

0

1487

.17

1276.9

2

1144.7

91062

.81

Domperidone Formulation

Overlay spectra

Figure 3 Overlapping of FTIR spectra

TABLE 5: VIBRATION FREQUENCY OF FT-IR SPECTRA OF

DOMPERIDONE

Sr. No. Functional Group Frequency (cm-1)

drug formulation

1 N-H stretching 3108 3120

4 C=O stretching 1717 1720

5 N-H Bending 1684 1684

7 C-O 1250 1250



Upon comparing the IR spectra of the formulation with that of the pure drug (figure 5.1),

it was noticed that the characteristic peaks of the pure drug were also present in the

sample spectra revealing the inert nature of the carrier used for formulation. Overlapping

of IR spectra indicate no significant difference in characteristic peak at wave numbers of

the drug in presence of the excipients.

DSC study:

Figure 4 DSC study of drug

Figure 5 DSC study of drug complex



From the study of DSC it was concluded that length of peak of drug was decrease and

width was increase in formulation it means solubility of drug was increased.

Evaluation of Domperidone Buccal Tablets:

Precompression Evaluation Parameters:

TABLE 6: PRECOMPRESSION EVALUATION OF FORMULATED

INCLUSION COMPLEX AND EXCIPIENTS

Parameter Angle of repose(0)

bulk density (g/ml)

Tap density (g/ml)

Hausner’s ratio

Carr’s Index (%)

D1 26.28±0.2 0.494±0.05 0.565±0.04 1.14±0.07 12.57±0.04 D2 24.30±0.5 0.510±0.04 0.582±0.02 1.14±0.05 12.37±0.05 D3 27.14±0.3 0.515±0.02 0.593±0.05 1.15±0.04 13.15±0.03 D4 23.65±0.4 0.526±0.05 0.583±0.02 1.11±0.03 9.83±0.07 D5 25.22±0.2 0.534±0.02 0.602±0.03 1.13±0.02 11.30±0.03 D6 25.13±0.5 0.495±0.05 0.567±0.06 1.15±0.05 12.70±0.04 D7 24.19±0.6 0.498±0.03 0.560±0.04 1.13±0.06 11.07±0.02 D8 27.11±0.4 0.527±0.04 0.583±0.05 1.11±0.07 9.60±0.06 D9 25.32±0.6 0.493±0.04 0.575±0.07 1.17±0.05 14.26±0.05

Post-compression Evaluation Parameters:-

Tablets of each formulation were evaluated for parameters such as thickness, diameter,

weight variation, hardness, friability and drug content in given table.

TABLE 7: POST COMPRESSION EVALUATION OF FORMULATED

INCLUSION COMPLEX AND EXCIPIENTS

Batch Code

Thickness (mm)±SD

Weight variation (mg)±SD

Hardness (Kg/cm2)±SD

Friability (%)±SD

Drug content

(mg)±SD

Surface pH±SD

2.03±0.03 149±0.27 5.2±0.22 0.63±0.05 9.79±0.04 6.75±0.02 D2 2.05±0.05 149±0.90 5.4±0.14 0.55±0.02 9.75±0.15 6.73±0.05 D3 2.02±0.07 151±0.75 5.5±0.19 0.52±0.05 9.92±0.30 6.66±0.06 D4 2.14±0.08 150±0.35 5.6±0.34 0.57±0.03 9.97±0.12 6.68±0.04 D5 2.05±0.02 147±0.85 5.4±0.15 0.56±0.05 9.99±0.36 6.62±0.05 D6 2.02±0.03 148±0.30 5.6±0.20 0.61±0.12 9.86±0.14 6.70±0.02 D7 2.05±0.04 149±0.37 5.3±0.28 0.54±0.10 9.95±0.31 6.65±0.07 D8 2.11±0.06 148±0.63 5.2±0.32 0.60±0.05 9.94±0.15 6.68±0.03 D9 2.03±0.04 151±0.72 5.4±0.21 0.54±0.08 9.82±0.06 6.77±0.01



In-Vitro Drug Release Study:

TABLE 8: IN-VITRO DISSOLUTION STUDY OF FACTORIAL BATCHES D1-

D9

The release of Domperidone from buccal tablets varied according to the ratio and

concentration of Carbopol 934P and HPMC K4M polymers.

From dissolution study it was found that D1, D2 and D3 formulations having 10%

concentration of polymers but in ratio of 1:2, 1:1 and 2:1 respectively, it shows 92.28%,

89.65% and 87.30% release after 8 hours it shows in same concentration of polymers

release decreased because of ratio of polymers, D1 to D3 Carbopol 934P increase and

release was decrease so, it shows in formulation which having higher rate of Carbopol

934P shows lowering the release. In D4, D5 and D6 batches 15% of polymer

concentration so, lower release rate and as concentration of Carbopol 934P increase

release rate was decreased it shows 87.80%, 84.74% and 82.60% release respectively. In

D7, D8 and D9 formulations retardation of release was higher than other because higher

concentration of polymers.

Time(hr.) D1 D2 D3 D4 D5 D6 D7 D8 D9

1 38.02 36.25 33.22 34.11 33.75 31.26 33.58 29.66 26.64

2 51.22 43.55 41.74 42.99 40.14 38.16 39.43 35.12 33.66

3 58.13 51.10 49.45 49.82 49.97 48.68 48.18 44.72 40.23

4 64.75 61.39 58.12 55.83 57.05 55.03 53.64 51.74 47.03

5 74.46 68.04 63.49 66.16 61.16 59.49 65.20 56.34 56.03

6 81.59 77.24 71.94 69.83 71.37 67.00 71.17 65.43 62.63

7 86.65 83.86 81.53 77.62 79.71 74.06 77.55 73.72 67.86

8 92.28 89.65 87.30 87.80 84.74 82.60 85.41 80.65 76.16



Figure 6 In-vitro release of factorial batches D1-D3





Swelling Study of Prepared Tablets:

The swelling index of the tablets was increased with increasing concentration of polymer

absorbed large volumes of water rapidly and swells to its maximum hydrated size without

dissolving in aqueous media,

TABLE 9: SWELLING INDEX OF FACTORIAL BATCHES D1-D9

Batch code Swelling index (%) D1 40.21 D2 33.40 D3 30.11 D4 53.58 D5 45.14 D6 40.35 D7 58.45 D8 50.12 D9 48.30

Mucoadhesive strength of Prepared Tablets:

Mucoadhesive strength was determined by using self developed force detachment method

and observed within the range of 15.26 to 35.68gm. From study it was observed that as



ratio of Carbopol 934P increase the mucoadhesion was increase. Decreasing the content

of the Carbopol 934P resulted in decreased adhesion force.

TABLE 10: MUCOADHESIVE STRENGTH OF FACTORIAL BATCHES D1-D9

Kinetic of Domperidone Buccal Tablets:-

In 32 full factorial design study, the effect of combination of independent variables i.e.

ratio of polymer (Carbopol: HPMC K4M) (X1), concentration of polymers (Carbopol and

HPMC K4M) (X2), on dependent variables Q8 (Cumulative percentage drug release after

8 hr), swelling index and mucoadhesive strength. A statistical model incorporating

interactive and polynomial terms was used to evaluate responses.

To know the mechanism of drug release from these formulations the data were treated

according to first-order (log cumulative percentage of drug remaining vs. time),

Higuchi’s (Cumulative percentage drug released vs. squared root of time & Korsmeyer

and peppas (log cumulative percentage drug released vs. time) pattern. The results of

kinetic treatment applied to dissolution profiles of tablet of each batch were shown in

table 5.16. All the formulation follows the zero order patterns as compare to first order.

Zero order Correlation co-efficient value is nearest to 0.999 as compare to first-order

correlation co-efficient value. Here zero order values are between 0.993 – 0.999 and first

order values are between 0.983 – 0.990.

Formulation code

Mucoadhesive strength (gm)

D1 15.26 D2 20.93 D3 30.34 D4 18.24 D5 25.03 D6 32.77 D7 27.09 D8 29.22 D9 35.68



TABLE 11: RESULTS OF DEPENDENT VARIABLES FOR 32 FULL

FACTORIAL DESIGNS

The kinetic of the dissolution data were well fitted to zero order, Higuchi model and

Krossmayer-Peppas model as evident from regression coefficients (Table 11). In case of

the controlled release formulations, diffusion, swelling and erosion are the three most

important rate controlling mechanisms. Formulation containing swelling polymers show

swelling as well as diffusion mechanism because the kinetic of swelling include

relaxation of polymer chains and imbibitions of water, causing the polymer to swell and

changing it from a glassy to rubbery state. The value of diffusion exponent n for most

factorial formulations is between 0.425-0.512 (Table 11) indicating Fickian drug release

from the formulations.

TABLE 12: KINETIC TREATMENT OF DISSOLUTION PROFILE OF BATCH

D1-D9

D1 D2 D3 D4 D5 D6 D7 D8 D9

Zero Order Model

B 7.584 7.862 7.742 7.373 7.417 7.122 7.547 7.341 7.069

A 34.261 28.502 26.008 27.344 26.359 24.986 25.306 21.638 19.466

R2 0.993 0.998 0.999 0.997 0.997 0.997 0.998 0.998 0.999

First Order Model

B 0.052 0.057 0.059 0.056 0.057 0.058 0.058 0.062 0.064

A 1.586 1.531 1.501 1.513 1.501 1.477 1.490 1.438 1.398

Batch code Q8

Swelling index

Mucoadhesive strength

D1 92.28 40.21 15.26 D2 89.52 33.4 20.93 D3 87.32 30.11 30.34 D4 87.74 53.58 18.24 D5 84.64 45.14 25.03 D6 82.41 40.35 32.77 D7 85.32 58.45 27.09 D8 80.93 50.12 29.22 D9 76.09 48.3 35.68



R2 0.971 0.987 0.988 0.988 0.988 0.983 0.990 0.990 0.988

Higuchi Model

B 29.709 30.460 29.936 28.471 28.670 27.599 29.120 28.283 27.299

A 7.834 1.796 -0.170 2.490 1.299 0.780 -0.085 -2.974 -4.363

R2 0.998 0.992 0.991 0.988 0.989 0.991 0.988 0.987 0.990

Korsmeyer and Peppas Model

n 0.425 0.454 0.470 0.445 0.456 0.466 0.464 0.492 0.512

k 0.375 0.335 0.311 0.322 0.312 0.294 0.306 0.271 0.246

R2 0.997 0.987 0.990 0.987 0.986 0.990 0.982 0.984 0.988 B = Slope, A = Intercept, R2 = Square of Correlation co-efficient, n = diffusion

exponent

Full and Reduce Model for Q8:

Surface response plot to depict the polymer ratio (x1) and polymer concentration (x2) on

Q8, swelling index and mucoadhesive strength.

Full Model of Q8 = 84.8 - 3.25 X1 - 4.46 X2 + 0.163 X11 + 0.313 X22 - 1.07 X12 (Eq.

3.1) Reduce Model of Q8 = 85.1 - 3.25 X1 - 4.46 X2 - 1.07 X12

(Eq. 3.2)

From the reduced model generated based on study of magnitude of co-efficient and the

mathematical sign it carries, the above polynomial equations can be used to draw the

conclusion regarding the influence of independent variable on the given dependent

variables. The positive and negative coefficient value of independent variables indicates

the change in response of dependable variable. The results of reduced model depicts that

dependable variable Q8 has negative signs of coefficients of factor X1 and X2 which

indicates as there was increase in concentration and ratio of polymers from 1:2, 1:1 to 2:1

was decrease in release of drug at 8 hr.

Full and Reduce Model for Swelling Index

Full Model of swelling index = 44.4 - 5.58 X1 + 8.86 X2 + 2.28 X11 - 2.93 X22 - 0.013 X12

Reduce Model of swelling index = 42.9 - 5.58 X1 + 8.86 X2 + 2.28 X11 (Eq. 3.4)

The results of reduced model depicts that dependable variable swelling index has

negative signs of coefficients of factor X1 which indicates as there was increase in ratio



of polymers, means increase in concentration of matrix forming polymer HPMC K4M

from 1:2 to 1:1 and 2:1 was decrease in swelling index of tablet.

Full and Reduce Model for Mucoadhesive Strength

Full Model of mucoadhesive strength = 24.3 + 6.37 X1 + 4.24 X2 + 1.50 X11 + 1.07 X22 -

1.62 X12 (Eq. 3.5)

Reduce Model of mucoadhesive strength = 26.1 + 6.37 X1 + 4.24 X2 (Eq. 3.6)

The results of reduced model depicts that dependable variable mucoadhesive strength has

positive signs of coefficients of factor X1 and X2 which indicates as there was increase in

concentrations and ratio of polymers from 1:2 to 1:1 and 2:1 was increase in

mucoadhesive strength of tablet because of mucoadhesive polymer Carbopol 934P.



Figure 9 Response surface plot of Q8, Swelling Index and Mucoadhesive Strength

TABLE 13: CALCULATIONS OF TESTING MODEL IN PORTIONS

For Q8

Regression

FM RM

DF SS MS F R2 FCal. FCrit.

DF = (1,5) 5.00 187.84 37.57 94.14 0.994

0.31

9.55

3.00 187.59 62.53 216.08 0.992 Error FM

RM 3.00 1.20 0.40 - - 5.00 1.45 0.29 - -

For swelling index

Regression FM RM


DF = (1,5) 5.00 685.15 137.03 98.68 0.994

3.74

9.55

3.00 674.75 224.92 77.22 0.979 Error FM

RM 3 4.17 1.29 - -

5.00 14.56 2.91 - - For Mucoadhesive strength

Regression

FM RM


DF = (3,3) 5.00 368.60 73.72 63.05 0.991

4.95

9.27

2.00 351.24 175.62 50.51 0.944 Error FM

RM 3.00 3.51 1.17 - - 6.00 20.86 3.48 - -



SELECTION OF OPTIMUM BATCH

The values of similarity factor (f2) for the batch D1 showed maximum f2 value 72.43 as

shown in Table 5.10. Hence, formulation batch D1 was considered as optimum batch.

TABLE 14: SIMILARITY FACTOR (F2) FOR BATCHES D1-D9

Figure 10 Comparisons of ex-vivo permeation study

Batch Similarity factor (f2) Dis-similarity factor (f1) D1 72.43 1.24 D2 61.51 7.75 D3 52.82 12.13 D4 51.38 12.60 D5 49.82 13.74 D6 44.57 17.64 D7 49.08 14.41 D8 41.23 21.05 D9 36.76 15.95



TABLE 15: EX-VIVO PERMEATION STUDY OF OPTIMIZE BATCH

Time(hr.) Ex-vivo Release of D1 batch

In-vitro Release of D1 batch

0 0.00 0.00 1 33.75 38.02 2 45.84 51.22 3 53.59 58.13 4 61.23 64.75 5 67.35 74.46 6 76.01 81.59 7 84.04 86.65 8 89.12 92.28

RESULTS OF ACCELERATED STABILITY STUDY

In order to determine the change in in-vitro release profile on storage, stability study of

formulation D1 was carried out at 40°C in a humidity jar having 75 % RH. Samples

evaluated after one month showed no change in-vitro drug release pattern as shown in

Table 16. The value of similarity factor (f2) was 81.53 (Table 16) indicating good

similarity of dissolution profiles before and after stability studies. The similarity factor

must be above 50. If the similarity factor value is near to 100, similarity factor is very

good. The comparative dissolution profile of before and after accelerated stability study

showed in figure 11.

TABLE 16: ACCELERATED STABILITY STUDY

Time (hr) CPR (Initial)

CPR (After storage at 40o C for 1month)

0 0 0 1 38.02 37.49 2 51.22 49.61 3 58.13 56.69 4 64.75 63.12 5 74.46 71.56 6 81.59 78.8le4 7 86.65 85.30 8 92.28 90.03

Similarity factor (f2) 67.49 Dissimilarity factor (f1) 3.86



Figure 11 Accelerated Stability Study

CONCLUSION

Mucoadhesive bilayer buccal tablets contains Domperidone drug, Carbopol 934P and

HPMC K4M as polymers. Mucoadhesive bilayer buccal tablets of Domperidone

composed of a drug containing core layer of Carbopol 934P: HPMC K4M and backing

layer ethyl cellulose. Magnesium stearate, lactose and sweetening agents. Tablets of all

formulations showed good physical appearance, both layers of the tablet were easily

distinguishable. Weight variation tests showed that tablets of all formulations passes USP

specifications. Hardness and friability test indicates that, tablets of all formulations were

having good compactness and mechanical strength. The content uniformity of tablets

revealed that the drug was uniformly mixed in the polymers. The surface ph of tablets

was almost within the range of salivary pH. Swelling study showed that, HPMC

exhibited high swelling capacity and concentration of polymers increase the swelling

index. Mucoadhesive strength studies of all formulations showed that mucoadhesion was

increased with increasing concentration of Carbopol 934P. Highest mucoadhesion was

found in (2:1) combination of Carbopol and HPMC K4M. In-vitro dissolution studies

revealed that the drug release increased with decrease in concentration of Carbopol



934p.the high cumulative release was obtained in the formulation of (1:2 ratio of

Carbopol 934P and HPMC K4M) and 10% concentration of total polymer. The kinetic

data showed that the optimized formulations were followed diffusion and erosion

supported by regression coefficient(r) and followed non fickian behavior with nearly zero

order release pattern. Stability study for the three months at 40°C in a humidity jar having

75 % RH as specified by ICH guideline, revealed that the selected batch D1 was stable(f1

value<50%<f2 value).

REFERANCES

1. Gandhi PA “A review article on mucoadhesive buccal drug delivery system”Int.

J. Pharma Research and Dev., 2011, 3, 11.

2. European pharmacopoeia. 3 rd ed. Strasbourg: Council of European, Strasbourg;

1997. pp. 779-80.

3. British Pharmacopoeia. Vol. 1. London: HMSO; 2001. pp. 215.

4. Rowe RC, Shesky PJ and Owen SC. Hand book of pharmaceutical excipients;

3rd Edn; American pharmaceutical association, Washington publisher, 2000, pp

398, 1446, 1617.

5. Indian Pharmacopoeia, 6th Edn, the Indian Pharmacopoeia Commission,

Ghaziabad, Sept. 2010, Volume-I, pp 111-117.

6. ICH guideline Q1A- Q1F, www.ich.org/cache/compo/363-272-1.html.

7. Flese EF, Hugen TA. Preformulation, Lachman L., The theory and practice of

industrial pharmacy, 4th Edn, Varghese publishing house, Mumbai, 1987, pp 171-

293.

8. Indian Pharmacopoeia, volume I, Year 2010, 192-193.

9. Higuchi T. “Mechanism of sustained action mediation, theoretical analysis of rate

of release of solid drugs dispersed in solid matrices.” J. Pharm. Sci. 1963, 52,

1145-1149.

10. Korsmeyer RW, Gurny R, Doelker E, Buri P and Peppas NA. “Mechanism of

solute release from porous hydrophillic polymers.” Int. J. Pharma. 1983, 15, 25-

35.

For Correspondence: Rahul B. Patel Email: [email protected]

FORMULATION AND IN-VITRO EVALUATION OF … was a gift sample from CADILA Pharmaceuticals Pvt. Ltd....

Documents

Transcript of FORMULATION AND IN-VITRO EVALUATION OF … was a gift sample from CADILA Pharmaceuticals Pvt. Ltd....