3476 Int J Pharm Sci Nanotech Vol 9; Issue 5 September October 2016

Research Paper

Formulation and Evaluation of Modified Pulsincap as Pulsatile Drug Delivery System for Treatment of Rheumatoid Arthritis Chavda D. Hiral*, Sonpal N. Rakshit, Prajapati A. Paresh, and Madhabhai M. Patel Department of Pharmaceutics, ShankersinhVaghelaBapu Institute of Pharmacy, Bapu Gujarat Knowledge Village, Near Vasaniya Mahadev, Gandhinagar Mansa Road, Vasan, Gandhinagar – 382 650, Gujarat, India.

Received June 1, 2016; accepted July 19, 2016

ABSTRACT

The aim of the present study was to design and evaluate a modified pulsincap pulsatile drug delivery system of etodolac for treatment of rheumatoid arthritis. Capsule body was made water insoluble by cross linking with formaldehyde vapour. It was filled with drug, osmogen NaCl and super disintegrant sodium starch glycolate to expel the drug after predetermined lag time. A hydro gel plug made of HPMC K4M was placed in the capsule body to achieve desired drug release after lag time for chronotherapy of rheumatoid arthritis. Untreated cap was then fitted to the treated body was sealed. Entire unit was coated with 5% Eudragit S-100 to prevent variable gastric emptying. A 32 full factorial design was used for optimization in which concentration ratio of NaCl and SSG (X1), and the weight of hydrogel plug (X2) were selected as independent variables while lag time and t

90% were taken as

dependent variables. FTIR and DSC studies confirmed

drug excipient compatibility. Developed formulation was evaluated for in-vitro drug release in pH 1.2, phosphate buffer pH 6.8 and phosphate buffer pH 7.4. Statistical analysis confirmed the significance of selected independent variables. Response surface plot and contour plot indicate augmentation of the line toward the weight of hydrogel plug factor indicating greater significance. Formulation with highest desirability containing 34.4 mg of SSG, 137.6 mg of NaCl and 48 mg of HPMC K4M plug was selected as an optimized formulation as it provided the desired lag time of 6 hours and t

90% of about 477 mins.

Accelerated stability study performed on optimized formulation suggested stable and viable formulation. A stable, efficient formulation modified pulsincap of Etodolac as a pulsatile drug delivery system was developed with proposed increased patient compliance and improved dosage form efficiency.

KEYWORDS: Etodolac; Modified pulsincap; Chronotherapy; Rheumatoid arthritis.

Introduction

Rheumatoid arthritis is an autoimmune-mediated, systemic, inflammatory disease which is chronic and progressive in nature. It is the most common form of inflammatory arthritis and affects 1% of men and 3% of women (Trieb, 2005; Roger et al., 2008). It is based on the circadian rhythm of the body because peak pain occurs in early morning and decreases as the time passes. With conventional dosage forms either the patient would have to take the medication at night or early in the morning. If the patient would take the medication at night then when he wakes up early in the morning and when the pain is severe, he would not get significant benefit as the drug effect would have subsided during the night. Patient has to get up very early for medication so that the drug attains peak concentration when the pain is severe. These compulsions reduce the patient compliance severely. The above drawback can be overcome by formulating pulsatile drug delivery systems

wherein the patient takes medication at an appropriate and comfortable time but the drug gets released in pulses or after a predetermined lag time that could be designed according to the circadian rhythm of the body, in this case early in the morning when pain is severe. Pulsatile systems are gaining a lot of interest as they deliver the drug at the right site of action at the right time and in the right amount, thus providing spatial and temporal delivery and increasing patient compliance. The release of the drug as a pulse after a lag time has to be designed in such a way that a complete and rapid drug release follows the lag time. (Vinupama et al., 2014). For rheumatoid arthritis, a pulsatile drug delivery system could be designed where the patient takes the medication at night time. The medication remains intact during the night and starts releasing the drug only early in the morning such that the drug achieves its peak concentration and provides maximum benefit when the pain is severe early in the morning when the patient wakes up.

 

  

International Journal of Pharmaceutical Sciences and Nanotechnology

Volume 9Issue 5 September – October 2016

MS ID: IJPSN-6-1-16-HIRAL

ABBREVIATIONS: ETD: Etodolac; PDDS: Pulsatile drug delivery, RA: Rheumatoid arthritis; CDDS: Colon targeted drug delivery system; GIT: Gastro intestinal tract; BCS: Biopharmaceutical Classification System; DSC: Differential Scanning Calorimetry; FTIR: Fourier transform infrared spectroscopy; USP: United States Pharmacopoeia; ICH: International Conference on Harmonization.

3476

Chavda et al: Formulation and Evaluation of Modified Pulsincap as Pulsatile Drug Delivery System for Treatment of ... 3477 

Etodolac is a non-steroidal anti-inflammatory drug (NSAID) with anti-inflammatory, analgesic and antipyretic properties. Its therapeutic effects are due to its ability to inhibit prostaglandin synthesis. It is indicated for relief of signs and symptoms of rheumatoid arthritis. It is used for rheumatoid arthritis, including juvenile idiopathic arthritis, osteoarthritis, and for the treatment of acute pain. (Abd-Elbary et al., 2011).

The prepared modified pulsincap formulation will be taken by the patient at bed time roughly around 10:00 pm. After administration the formulation will remain intact in the stomach for the period of 2 hours & in small intestine for another 3. 5–4 hours due to insoluble coating. After 6 hours from administration, the formulation will reach the colon and the drug will be released in the colonic fluid and it will be rapidly absorbed. The tmax of Etodolac is about 2.8 hours. So, from start of absorption, after 2.5 – 3 hours, i.e. in early morning when the patient will wake up, the time to peak concentration of drug will be achieved and the patient will get relief from severe pain of the rheumatoid arthritis prevalent at early morning. (Dharmamoorthy and Nandhakumar, 2011; Srikanth et al., 2014; Rajput et al., 2012)

Therefore, we sought to design and evaluate a modified pulsincap pulsatile drug delivery system of etodolac for treatment of rheumatoid arthritis.

Materials and Methods

Reagents

Etodolac was gifted from the IPCA Pvt. Ltd. Sodium chloride, Sodium starch glycolate, Sodium alginate, Acetone and Methanol were obtained from the Astron chemicals (India) Pvt. Ltd. HPMC K4M and HPMC K100M was obtained from Seva fine chemicals, Ahmedabad. Cellulose acetate phthalate and Formaldehyde obtained from the Chemdyes Corporation, Ahmedabad. Potassium Permanganate was obtained from ACS chemicals, Ahmedabad. Empty gelatin capsules of size “0” were obtained from RutvikPharma, Ahmedabad.

Equipments

Weighing machine, Tablet punching machine, Monsanto hardness tester, Hot air oven, Dissolution apparatus, Dissolution apparatus, Dissolution apparatus, UV spectrometer, FTIR spectrometer, DSC analysis.

Methods Drug-excipients compatibility study Fourier transform infrared spectroscopic study: FT-IR

spectroscopic studies were performed to check the compatibility between drug and excipients. The FT-IR spectra of drug alone and physical mixture with all the excipients were obtained by KBr method and the peak corresponding to functional groups were compared.

Differential Scanning Calorimetry study: DSC measurements were carried out on a Shimadzu corporation, Japan DSC-60 differential scanning. The

accurately weighed sample was placed in an aluminum pan. An empty aluminum pan was used as reference. The experiment was carried out in Air atmosphere at scanning rate of 200C per min in the range of 20–300°C.

Preparation of cross linked gelatin capsules Formaldehyde treatment: Formalin treatment has

been employed to modify the solubility of gelatin capsules. Hard gelatin capsule of size ‘0’ and 50 in number were taken. Their bodies were separated from the caps. The formaldehyde solution 15% (v/v) was prepared in methanol and taken in the beaker. Then these solutions were put on to the hot plate. Vapors of formalin were generated from this reaction. The reaction time was optimized by removing capsule bodies at different time intervals and dried at 50°C for 30 min. The bodies were then dried at room temperature to facilitate removal of residual formaldehyde. These capsule bodies were capped with untreated caps and stored in a polythene bag.

Tests for formaldehyde treated empty capsules: Various physical and chemical tests were carried out simultaneously for formaldehyde treated and untreated capsules.

(a) Physical test: Identification attributes: The size ‘0’ capsule were one with a red cap and cream colored body. They were lockable type, odorless, softy and sticky when treated with wet fingers. After formaldehyde treatment, there were no significant changes in the capsules. They were non-tacky when touched with wet fingers. Visual defect: In about 50 capsule bodies treated with formaldehyde, about five were found to be shrunk or distorted. Dimensions: Variations in dimensions between formaldehyde, treated and untreated capsules were studied. The length and diameter of the capsules were measured before and after formaldehyde treatment, using dial caliper.

(b) Chemical test: Qualitative test for free formaldehyde: Standard formaldehyde solution used is formaldehyde solution (0.002 w/v) and sample solution is formaldehyde treated bodies (about 25 in number) were cut into small pieces and taken into a beaker containing distilled water. This was stirred for 1 hour with a magnetic stirrer, to solubilize the free formaldehyde. The solution was then filtered into a 50 ml volumetric flask, washed with distilled water and volume was made up to 50 ml with the washings. 1ml of sample solution, 9 ml of water was added. One ml of resulting solution was taken into a test tube and mixed with 4 ml of water and 5 ml of acetone solution reagent. The test tube was warmed in a water bath at –40oC and allowed to stand for 40 min. The was not more intensely colored than a reference solution prepared at the same time and in the same manner using 1ml of standard solution in place of the sample solution. The comparison should be made by examining tubes down their vertical axis.

3478 Int J Pharm Sci Nanotech Vol 9; Issue 5 September October 2016

Formulation of modified pulsincap drug delivery systems Preparation of powder blend: Drug etodolac was

mixed with osmogen NaCl and superdisintegrant SSG to form core physical mixture. Core physical mixture was passed through sieve no. 120 and then filled in capsule body.

Preparation of hydrogel plug: Hydrogel plug of three polymers HPMC K4M, HPMCK100M and Na-alginate were initially selected as they were swellable hydrophilic polymers and could control the lag time. Concentrations of these polymers were weighed and directly compressed using 6 mm punch in punching machine.

Filling of powder blend and hydrogel plug in capsule body: Weighed blend was placed in the formaldehyde treatment capsule and it was locked by hydrogel plug. Finally non-treated cap of the capsule was placed on it.

Sealing of capsules: Sealing solution of 0.25% ethyl acetate in ethanol was prepared. The cap was sealed with the body using this sealing solution.

Enteric coating of capsule: Enteric coating was done using 5% cellulose acetate phthalate and 5% Eudragit S-100 in acetone. Capsules were completely coated with coating solution to prevent variable gastric emptying. Coating was repeated until a 5% increase in weight was obtained. (Yezihaaz et al., 2014, Srinivas et al., 2013, Modi et al., 2013 and Patel et al., 2011)

Preliminary trial formulations of modified pulsincap Preliminary trial formulations were prepared to

finalize the excipients. Modified pulsincap pulsatile drug delivery system composed of formaldehyde treated capsule bodies and untreated caps. Drug was filled in the capsule body along with osmogen (NaCl) and super disintegrant (SSG) were added to form core physical mixture so as to achieve a desirable lag time. A hydrogel plug which further controls the drug release after lag time was placed above the physical mixture in the capsule body. HPMC K4M, HPMCK100M and sodium alginate were used for preparation of hydrogel plug. CAP was selected for enteric coating of entire capsule in the preliminary formulations P1 to P9 and Eudragit S100 for P10 to P15 and factorial formulations F1 to F9. The preliminary trial formulations are listed in Table 1 and Table 2.

Full factorial design A full factorial 32 design was used for optimization

where 2 factors were evaluated at 3 levels. The concentration ratio of NaCl and SSG and weight of HPMC K4M hydrogel plug were chosen as independent variables, while lag time and t90% were taken as dependent variables. Table 3 summarizes the independent variables along with their levels. The resulted formulations are shown in Table 4 and Table 5.

TABLE 1

Preliminary Trial Formulations: P1 – P9.

Ingredients (mg) P1 P2 P3 P4 P5 P6 P7 P8 P9 Etodolac 200 200 200 200 200 200 200 200 200Sodium chloride - 150 130 - 150 130 - 150 130Sodium starch glycolate - - 20 - - 20 - - 20HPMCK4M 200 200 200 - - - - - -HPMCK100M - - - 200 200 200 - - -Na alginate - - - - - - 200 200 200Weight of capsule 90.2 90.2 90.2 90.2 90.2 90.2 90.2 90.2 90.2Weight with capsule 490.2 640.2 640.2 490.2 640.2 640.2 490.2 640.2 640.2Total weight after coating(mg)

514.7 ± 1.3 672.2 ± 1.2 672.2 ± 1.5 514.7 ± 1.1 672.2 ± 1.6 672.2 ± 1.5 514.7 ± 1.3 672.2 ± 1.3 672.2 ± 1.6

(Coating solution: 5%w/v Cellulose acetate phthalate in acetone, 5% weight gain)

TABLE 2

Preliminary Trial Formulations: P10 – P15.

Ingredients (mg) P10 P11 P12 P13 P14 P15 Etodolac 200 200 200 200 200 200 Sodium chloride 130 130 80 130 160 - Sodium starch glycolate 20 20 20 20 40 - HPMCK4M 100 - 100 100 50 50 HPMCK100M - 100 - - - - Weight of capsule 90.2 90.2 90.2 90.2 90.2 90.2 Weight with capsule 540.2 540.2 390.2 540.2 540.2 340.2 Total weight after coating(mg) 567.2 ± 1.3 567.2 ± 1.5 409.7 ± 1.1 567.2 ± 1.4 567.2 ± 1.4 357.2 ± 1.2

(5%w/v Eudragit solution in acetone, 5% weight gain)

TABLE 3

Coding of Independent Variables

Coded values Actual values

X1(Concentration ratio of sodium chloride and sodium starch glycolate in mg) X2 (Weight of hydrogel plug in mg)

-1 150 (120:30) 40 0 200 (160:40) 50

+1 250 (200:50) 60

Chavda et al: Formulation and Evaluation of Modified Pulsincap as Pulsatile Drug Delivery System for Treatment of ... 3479 

TABLE 4

Full Factorial Design with Coded Value.

Formulation Etodolac (mg) X1 X2

F1 200 -1 -1 F2 200 0 -1 F3 200 +1 -1 F4 200 -1 0 F5 200 0 0 F6 200 +1 0 F7 200 -1 +1 F8 200 0 +1 F9 200 -1 +1

TABLE 5

Compositionof Factorial Formulations.

Ingredients (mg) F1 F2 F3 F4 F5 F6 F7 F8 F9 Etodolac 200 200 200 200 200 200 200 200 200Sodium chloride 120 160 200 120 160 200 120 160 200Sodium starch glycolate 30 40 50 30 40 50 30 40 50HPMCK4M 40 40 40 50 50 50 60 60 60Weight of capsule 90.2 90.2 90.2 90.2 90.2 90.2 90.2 90.2 90.2Weight with capsule 480.2 530.2 580.2 490.2 540.2 590.2 500.2 550.2 600.2Total weight after coating 504.2 ± 1.1 556.7 ± 1.2 609.2± 1.5 514.7 ± 1.5 567.2 ± 1.1 619.7 ± 1.1 525.2 ± 1.2 577.7 ± 1.5 630.2 ± 1.1

(5% Eudragit S-100 coating solution in acetone- 5% weight gain)

Statistical analysis Statistical analysis of the factorial design

formulations was performed by multiple regression analysis using Design Expert 7.0. Contour plots and 3D response surface plots were also constructed. Data was evaluated by t-test and one way analysis of variable (ANOVA) was applied to check significance of drug release from different formulations. A p value of less than 0.05 (p < 0.05) were considered to be significant.

Evaluation of modified pulsincap

Thickness of coating: The thickness of cellulose acetate phthalate and eudragit S 100 coating was measured using Vernier calipers and expressed in mm.

Weight variation: Twenty tablets were collected at random and were weighed collectively and individually. From the collective weight, average weight was calculated. The percent weight variation was calculated.

Drug content: 20 capsules were randomly selected from each batch of the prepared pulsincap of etodolac and the contents were removed and powdered. From this sample 100 mg powder was accurately transferred into a 100 ml volumetric flask. The solution is made up to volume with methanol. The resulted solution was filtered through 0.45 μm filter paper and suitably diluted and the drug content was estimated spectrophotometrically by measuring the absorbance at 276 nm.

Lag time: Lag time is the total time period after which the plug is ejected out of the capsule body and the drug releases immediately. Lag time was determined visually using phosphate buffer pH 6.8 and 7.4. For lag time determinations USP paddle apparatus was used. Capsules were tied with the paddle by cotton thread; temperature was maintained at 37°C at 50 rpm.

In-vitro drug release study: Dissolution studies were carried out by using USP XXIII dissolution test

apparatus (Basket) method. In order to simulate the pH changes along the GI tract, three dissolution media with pH 1.2, 6.8 and 7.4 were sequentially used referred to as sequential pH change method. When performing experiments, the pH 1.2 medium (0.1 N HCL) was first used for 2 hours (since the average gastric emptying time is 2 hours) then removed and the fresh pH 6.8 phosphate buffer was added. After 4 hours (average small intestinal transit time is 4 hours) the medium was removed and fresh pH 7.4 dissolution medium was added for subsequent hours. 900ml of the dissolution medium was used at each time. Rotation speed was 100 rpm and temperature was maintained at 37±0.5 °C. Aliquots were withdrawn at predetermined time intervals and simultaneously equal volume of fresh dissolution media was replaced to maintain sink conditions. The withdrawn samples were analyzed at 276 nm, by UV spectroscopy after suitable dilution. Cumulative percentage drug release was calculated and in vitro drug release profile was constructed. The in vitro drug release profile of optimized batch was then compared with that of a marketed product.

Stability study: Short term accelerated stability study was performed according to ICH and WHO guidelines. Optimized batch F10 was packed in an airtight amber glass bottles. The bottles were kept at 40˚C ± 2 ˚C / 75% RH ± 5% RH. The samples were withdrawn at 0, 15 days and 1 month and evaluated for stability by determining drug content and t90%. (Jagdale et al., 2014, Reddy SG et al., 2014, Nagaraja G et al., 2013 and ICH GUIDELINES, 2009)

Results and Discussion Drug-excipients compatibility study Fourier-Transform infrared spectroscopic study: The

compatibility study between drug and polymer was

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Chavda et al: Formulation and Evaluation of Modified Pulsincap as Pulsatile Drug Delivery System for Treatment of ... 3481 

Optimization of formaldehyde concentration & exposure time for cross-linking The solubility of the capsule bodies checked and it was

found that 15% v/v formaldehyde solution and 6 hours exposure times was optimum in which capsule bodies remained intact up to 12 hours in all the media as shown in Table 6. After formaldehyde treatment of 100 capsule bodies about 10 were found to be distorted. Then they were subjected to measurement of dimensions as shown in Table 7. From the observations of the cross linked capsule bodies it was found that there was slight decrease in the diameter and length after formaldehyde treatment.

TABLE 6

Solubility Study of Cross-Linked Capsule Bodies.

Formaldehyde conc. (%v/v)

Time of exposure (hours)

Observation in dissolution media

0.1 N HCL Phosphate buffer 6.8

Phosphate buffer 7.4

15% 6 Intact up to 12 hour

Intact upto 12 hour

Intact upto 12 hour

TABLE 7

Comparison of Dimensions of Capsule Bodies.

Parameter (mm) Before treatment After treatment

Avg. capsule length 7.10 6.62 Avg. diameter of capsule body 17.62 16.12 Avg. length of capsule body 20.56 19.04

Qualitative test for free formaldehyde: The formal-dehyde capsules were tested for the presence of free formaldehyde. The sample solution was not more intensely colored than the standard solution inferring that less than 20 μg and free formaldehyde is present in 25 capsules.

Evaluation of modified pulsincap preliminary formulations Lag time: From the results of lag time of preliminary

trial formulations, it was found that there is no significant effect of osmogen (NaCl) alone on the lag time but in combination with the superdisintegrant (SSG) it

helps in ejection of plug after lag time and releases the drug immediately as shown in Table 9.

TABLE 8

Evaluation of Hydrogel Plug of Trial Formulations.

Type of plug Thickness

(mm) Friability

(%)

Swelling index (%) (in 4 hours)

pH 6.8 pH 7.4 HPMCK4M 2.20 ± 0.05 0.7 50 ± 1.0 55 ± 1.5HPMCK100M 2.24 ± 0.06 0.8 45 ± 1.7 50 ± 1.0Na-alginate 2.22 ± 0.05 0.5 - -All values are mean ± S.D, n=3

TABLE 9

Lag Time of Preliminary Formulations.

Formulations Lag time (min) Formulations Lag time (min) P1 540 ± 2 P9 540 ± 4P2 600 ± 4 P10 540 ± 2P3 600 ± 2 P11 480 ± 3P4 570 ± 2 P12 510 ± 1P5 540 ± 3 P13 600 ± 2P6 510 ± 2 P14 370 ± 3P7 540 ± 2 P15 480 ± 4P8 600 ± 1

In-vitro drug release study of preliminary formulations In the formulation P1 to P9, it was found that it did

not give the desired lag time and drug release because of the higher concentration of the hydrogel plug and in which CAP did not give the desired lag time. So, 5% Eudragit S–100 was selected for enteric coating of the capsule. In the formulation P10–13, the weight of hydrogel plug and concentration ratio of NaCl and SSG were decreased respectively but still it did not give the desired lag time and drug release. Formulation P14 having the ratio of NaCl to SSG was 80:20 (160 mg NaCl and 40 mg SSG) and the HPMCK4M plug of 50 mg weight gave the desired drug release 101.95% upto 8.5 hours and lag time of about near to 6 hour Hence it was used for the setting of levels and factors for the 32 full factorial designs as shown in Figure 3.

Fig. 3. (a)

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P5

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P7

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(a) P1 to P9

3482 Int J Pharm Sci Nanotech Vol 9; Issue 5 September October 2016

Fig. 3. (b) In vitro Drug Release Study of Preliminary Formulations (a) P1 – P9 (b) P10 – P15.

Fig. 4. In vitro Drug Release Study of Factorial Formulations.

Evaluation of modified pulsincap factorial formulations The drug content of the prepared capsules was found

to be in the range (not less than 98% to not more than 102%). The drug content values for all the capsules were within the acceptable limits indicating that there was no loss of drug during the process of filling. The weight variation was found in all desired formulations. All capsules passed weight variation test as the average percentage weight variation was within 7.5% limits as prescribed in the pharmacopoeia.These evaluation parameters are listed in Table 10.

TABLE 10

Evaluation of Factorial Formulations.

FormulationsThickness of coating(mm)

Drug content (%) Weight Variation

F1 0.052 ± 0.001 98.94 ± 0.4 505.8 ± 1.5 F2 0.052 ± 0.001 99.24 ± 0.9 557.0± 2.3 F3 0.058 ± 0.002 100.37 ± 0.3 607.6± 4.5 F4 0.052 ± 0.002 98.25 ± 0.3 516.3± 1.9 F5 0.051 ± 0.002 100.43 ± 0.2 568.8± 1.4 F6 0.055 ± 0.003 99.72 ± 0.4 619.9± 4.6 F7 0.058 ± 0.002 101.37 ± 0.4 526.9± 4.1 F8 0.052 ± 0.002 98.90 ± 0.7 618.6± 2.8 F9 0.055 ± 0.003 99.10 ± 0.3 633.3± 3.5

0

20

40

60

80

100

120

0 2 4 6 8 10

%Cumulative drug release

Time (hr)

F1 to F9

F1

F2

F3

F4

F5

F6

F7

F8

F9

Chavda et al: Formulation and Evaluation of Modified Pulsincap as Pulsatile Drug Delivery System for Treatment of ... 3483 

Fig. 5. In vitro Drug Release Study of Factorial Formulations.

In-vitro drug release study of factorial formulations Factorial formulation of F1-F9 showed distinctly

different lag time and drug releases. Upon contact with dissolution media the hydro gel plug starts to swell and due to pressure inside the capsule body plug comes out. So both the parameters affected the lag time. F1, F2 and F3 showed the drug release 105.77%, 105.62%, 105.5% at 7, 8.5, and 8.5 hours respectively. While formulations F4, F5 and F6 showed the drug release 100.07%, 104.97%, and 104.8% at 8, 8.5 and 8.5 hours respectively. Whereas, batches F7, F8 and F9 showed the drug release 99.52%, 104.82%, and 100.98% at 8, 8.5 and 8.5 hours respectively as shown in Figure 5. Due to enteric coating by Eudragit S-100 pulsincap remained intact in 0.1N HCL but starts to dissolve in phosphate buffer. It was postulated that after the dissolution of coating the cap starts to dissolve and fluid enters the body because it was insoluble but permeable. After entering the body, the osmogen and superdisintegrant creates the pressure on swollen plug and hence plug ejected out of the body.

Statistical analysis The statistical analysis of the factorial design batches

was performed multiple quadratic regression analysis. The lag time and t90% were evaluated as shown in Table 11.

TABLE 11

Value of Dependent Variables

Formulations Lag time (min) t90%

F1 280 388 F2 325 490 F3 375 479 F4 320 459 F5 370 489

F6 400 502 F7 425 530 F8 435 522 F9 450 525

Statistical analysis of lag time Polynomial equation for lag time Full model: Y1 = +364.44 + 33.33A + 55.00B + (-17.50) AB +

(-1.67A2) + (-18.33B2); R2=0.9725 The p value for A, B, AB, A2 and B2 was found to be

0.0022, 0.0005, 0.0238, 0.7930 and 0.0511 respectively. In which, A2 and B2 were found to be not less than 0.05. Thus polynomial terms A2 and B2 had no significant effect on the dependent variables Y1 (Lag time). So, reduced model was developed to obtain a better fit.

Reduced model: Y1 = 375.56 + 33.33A + 55B + (-17.5AB); R2= 0.9973 The p value for A, B and AB was found to be 0.0016,

0.0002 and 0.0461 respectively which is less than 0.05. Thus, A, B and AB has significant effect on the dependent variables Y1 (Lag time).

Contour plot and Response Surface Plot for lag time Contour plot and Response Surface Plot was drawn

using design expert 7 to understand the effect of Concentration ratio of NaCl and SSG and Weight of hydrogel plug on lag time. They are shown are Figure 6.

ANOVA for Lag time From the ANOVA results, values of p less than 0.05

indicate model terms are significant. Here, terms A and B are significant. Response surface plot and Perturbation plot indicate the augmentation of the line toward the B factor. So, factor B (weight of hydrogel plug) is more significant as shown in Table 12.

0

20

40

60

80

100

120

0 2 4 6 8 10

%Cumulative drug release

Time (hr)

F1 to F9

F1

F2

F3

F4

F5

F6

F7

F8

F9

3484

Fig. 6. (a) Con Lag Tim

TABLE 12

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after lag timFormulation w

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ning

3486 Int J Pharm Sci Nanotech Vol 9; Issue 5 September October 2016

34.4 mg of SSG, 137.6 mg of NaCl and 48 mg of HPMC K4M plug was selected as an optimized formulation as it provided the desired lag time of 6 hours and t90% of about 477 mins.

Check point analysis Validation of factorial design was carried out using

check point analysis by preparing an extra design check point batch. Extra design check point batch was prepared and the response was predicted using the developed model and then compared with experimentally determined response using t test. The p value was found to be 0.1127 for lag time and 0.06452 for t90%. A p value of greater than 0.05 indicated non-significant difference between the measured and predicted response thus validating the design.

Comparison with marketed formulation In the in-vitro drug release comparison of optimized

formulation with the marketed formulation, it showed

that marketed formulation gave the continuous drug release while pulsincap formulation gave the maximum effect of drug after the 6 hours when patient would be having a severe pain. The comparison was shown in Figure 8.

Stability study of optimized batch The selected optimized formulation was evaluated for

short term accelerated stability studies by storing finished formulationat 40˚C ± 2 ˚C / 75% RH ± 5% RH. The results are shown in Figure 9. The residual drug content of formulations was found to be 99.8%, 98.9%, 98.5% at the end of 0, 15 and 30 days and was within the permissible limits. While results of t90% for 0, 15 days and 1 month duration was found to be 504,505,510, respectively. So, it concluded that there was no significant change in the prepared formulation and can be deemed stable.

Fig. 8. Comparison of in vitro Drug Release Profile of Optimized and Marketed Formulation.

Fig. 9. Stability Study of Optimized Formulation.

Chavda et al: Formulation and Evaluation of Modified Pulsincap as Pulsatile Drug Delivery System for Treatment of ... 3487 

Conclusions

Based on the in vitro drug release study, it was found that formulation with highest desirability of 0.9 containing 34.4 mg of SSG, 137.6 mg of NaCl and 48 mg of HPMC K4M plug was selected as an optimized formulation. It prevented any drug release in the stomach and intestine but release the entire contents as soon as the formulation reached colon. It also provided desired lag time of 6 hours and t90% of about 477 mins. Hence, it can be concluded that the prepared modified pulsincap pulsatile drug delivery system of Etodolac can be considered as one of the promising formulation technique for chronotherapeutic management of rheumatoid arthritis and can be applied for other drugs as well. Further detailed in vivo studies must be carried out for demonstrating viability of this formulation.

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Reddy SG, Sirisha B, Rao VUM, VijayaLakshm P, and Ajitha A. (2014). Formulation and in vitro Evaluation of Colon Specific Drug Delivery of Naproxen Sodium by using Pulsincap Technology. An International Journal of Advances in Pharmaceutical Sciences, 5(1): 1751-1760.

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Yezihaaz, Babu KM, Vasavi CM, Murali KGV and Kumar KNP. (2014). Design And Development of Metoprolol Succinate Pulsincap Technology Chronotherepeutic System using Natural Gum as a Material for Colon Targeting. International Journal of Pharmaceutical, Chemical and Biological Sciences, 4(2): 317-327.

Address correspondence to:  Chavda D. Hiral, Department of Pharmaceutics, Shankersinh Vaghela Bapu Institute of Pharmacy, Bapu Gujarat Knowledge Village, Gandhinagar – Mansa Road, Vasan, Gandhinagar – 382650, Gujarat, India. Ph: +91 8511396677; E-mail: rsonpal.mpharm1985@gmail.com