INTERNATIONAL JOURNAL OF PHARMACEUTICAL RESEARCH AND BIO-SCIENCE

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1 INTERNATIONAL JOURNAL OF PHARMACEUTICAL RESEARCH AND BIO-SCIENCE FORMULATION AND EVALUATION OF SUSTAINED RELEASE PELLETS OF BOSENTAN HCl SIDDHI V. PATEL 1,2, DR. MUKESH S. PATEL 2 1. Research scholar, Gujarat Technological University, Gujarat. 2. Department of Pharmaceutics, Shri B. M. Shah College of Pharmaceutical Education and Research, Modasa , Gujarat, India. Accepted Date: 10/04/2016; Published Date: 27/04/2016 Abstract: The objective of present study was develop Bosentan HCl pellets, sustained release Dosage form, for the treatment of pulmonary arterial hypertension Diseases. Drug Excipients Compatibility study was performed through FTIR and DSC revealed that there no interaction between drug and polymers. Pellets were prepared by Extrusion-Spheronization technique using different Concentration of HPMC K 100, Eudragit RS 100, and Eudragit RL 100. Prepared formulation was subjected to Evaluation parameter like Bulk density, Tapped density, Hausner ratio, Carr s index, Angle of repose, % yields of pellets, %drug loading, %Friability, Mean particle size. In vitro dissolution study in 0.1 N HCl (ph 1.2) for first 2 hours followed by phosphate buffer (ph 6.8) for remaining 10 hours. The optimized formulation batch (F6) on the basis of acceptable pellets properties and In vitro drug release study F6 batch was found to 99.1% drug release at 12 hour. The formulation meet the needed theoretical drug release profile and has the sustain action i.e. retarding the drug release so the release is for the long time. Keywords: Bosentan HCl, Sustained release pellets, Extrusion-spheronization, Eudragit RS 100, Eudragit RL 100 Corresponding Author: MS. SIDDHI V. PATEL Access Online On: PAPER-QR CODE How to Cite This Article: 124

2 INTRODUCTION Bosentan HCl is an antihypertensive drug. It is used as pulmonary arterial hypertension. It is endothelial receptor antagonist. The administered bosentan HCl is antihypertensive drug is BCS II So, it has low solubility and high permeability. Its half life is 5 hours. To require Prepared sustained release pellets of bosentan hcl and improves patient compliance and increase efficiency in the treatment. The oral route of administration for sustained release systems has received greater attention because of more flexibility in dosage form design.oral drug delivery has been known for decades as the most widely utilized route of administration. Conventional drug therapy typically involves the periodic dosing of a therapeutic agent conventional method of formulation is quite effective. Sustained release systems include any drug delivery system that achieves slow release of drug over an extended period of time. Sustained release dosage forms provide a better control of plasma drug level. Control release systems denotes systems which can provide some control whether this be of a temporal or partial nature or both of drug release in the body. The pellets can be utilized to provide a controlled release of drug. Pellets disperse freely in GIT so, maximum absorption of drug and reduce peak plasma fluctuation. To prepare sustained release pellets without coating by extrusion spheronization process is to produce pellets of uniform size with high drug loading capacity. Pellets are recommended for patient with difficulty in swallowing and dysphasia like in case of children and geriatrics patients. MATERIAL AND METHOD Materials Bosentan HCl was purchased from Alembic Pharmaceutical Ltd. Eudragit RS 100 and RL 100- Evonik degusa India Pvt. Ltd, Mumbai, Avicel PH 101- Chemodyes Corporation, PVP K 30- Tuton Pharma, Ahmedabad. Preliminary Studies Determination of λ max UV spectrophotometric study of Bosentan HCl was carried out to identify λ max of drug in 0.1 N HCl and 6.8 ph phosphate buffer. The prepared solution was scanned from 200 to 400 nm in UV spectrophotometer. The wavelength of the maximum absorption was noted and UV spectrum was recorded. 125

3 Standard calibration curve of Bosentan HCl A stock solution of Bosentan HCl of concentration 100µg/ml was prepared in 0.1 N HCl and 6.8 ph phosphate buffer. The calibration curves were constructed using standard solution in the range 2-16µg/ml diluted with appropriate solvent. The assignments were represented in Table.7, 8 and Figure. 7, 8. Drug Excipient Interaction Study FTIR of Bosentan HCl, Eudragit RS 100 and Eudragit RL 100 were recorded using KBr mixing method. Drug-excipient interactions play a vital role in the release of drug from formulation. The drug bosentan HCl and formulation previously ground and mixed thoroughly with KBr, an infrared transparent matrix, at 1:10 or 1:100 (sample: KBr) ratio respectively. The KBr discs were prepared by compressing the powders. The samples were scanned between cm-1. METHOD OF PREPARATION OF SUSTAINED RELEASE PELLETS In prepared the pellets by using Extrusion spheronization technique. Pellets was prepared batch F1-F9 with various concentration of Polymer (Eudragit RS 100, Eudragit RL 100).In the Factorial Study, Avicel PH 101 used as a spheronizing agent. In this study, (2%) PVP K 30 in water was used to prepared dump mass. All the Factorial formulation contains bosentan HCl as an active ingredient. Eudragit RL 100, Eudragit RS 100 are used to polymer (matrix forming agents). All ingredients were mixed in double cone minimixer. In above mixture 2 % PVP K-30 water was added to make dump mass. Prepare dump mass were subjected to undergoes to extrusion (using 1mm sieve) then, resultant extrudate was spheronized equipped with 4.2 mm friction plate at various rotational speed and time. Pellets were formed and collected in tray. Table 1: Formulation of SR pellets Factorial Batches (F1-F9) using 3 2 Full Factorial Designs Ingredients (%) FORMULATION BATCH CODE (%) F1 F2 F3 F4 F5 F6 F7 F8 F9 Bosentan HCl Eudragit RS Eudragit RL Avicel PH % PVP K-30 in Water q.s. q.s. q.s. q.s. q.s. q.s. q.s. q.s. q.s. 126

4 Evaluation of pellets: 1) Loose Bulk Density: Weigh accurately 5 gm of pellets, and transferred in 100ml graduated cylinder. Carefully level the powder blend without compacting, and read the unsettled apparent volume (Vo). Calculate the apparent bulk density in gm/ml by the following formula: Bulk Density = Mass/apparent volume 2) Tapped Bulk Density: Weigh accurately 5 gm of pellets, and transferred in 100 ml 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 750 times 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 = Mass/tapped volume 3) Carr s index: The Compressibility index of the pellets was determined by Carr s compressibility index. It is a simple test to evaluate the bulk density and tapped density of a pellets and the rate at which it packed down. The formula for Carr s index is as below: Carr s Index = Tapped Density-Bulk Density 100/ Tapped Density 4) Hauser s Ratio: The Hauser s ratio is a number that is correlated to the flow ability of a pellets material. Hauser s Ratio = Tapped density/bulk Density Table 2: Effect of Carr s index and Hausner s ratio and flow property Carr s index Flow Character Hauser s ratio 10 Excellent Good Fair Passable

5 26-31 Poor Very poor Very, Very poor ) Angle of Repose: The angle of repose of powder blend powder was determined by the funnel method. The pellets were taken in the funnel. The height of the funnel was adjusted in such a way the tip of the funnel just touched the apex of the pellets. The pellets were allowed to flow through the funnel freely on to the surface. he diameter of the pellets cone was measured and angle of repose was calculated using the using following Equation. Angle of Repose (Ø) = tan -1 (h/r) Where, h = Height of the pellets cone r = Radius of the pellets cone Table 3: Effect of angle of repose on flow property Angle of Repose Type of flow <20 Excellent Good Passable <35 Very poor 6) Particle size and size distribution: The particle size and size distribution of the pellets produced was determined by agitation for 10 min with a sieve shaker fitted with a progression of standard sieves. From the weight retained on each sieve particle size is determined from standard sieve aperture size as per Indian pharmacopeia. 7) % Friability: Accurately weight quantity of pellets 4 gm were taken from final batch of pellets and placed in a friabilator and tumbled for 100 revaluations at 25 rpm. Twelve steel balls (weighing gm each) were used as attrition agent. Subsequently, the pellets were sieved through sieve no. 20. The weight loss (%) is calculated as: % F= (Wi Wr/ Wi) 100 Where, Wi= initial weight of pellets before friability testing, and 128

6 Wr = the weight of pellets retained above the sieve after friability testing. 8) % Drug Loading: The pellets were crushed and the powder equivalent of 100 mg of drug was dissolved in 20 ml methanol and then transferred to100 ml of 0.1 N HCl in volumetric flask. The solution was analyzed at 247 nm using double beam UV-Vis spectrophotometer after suitable dilution. The content of drug was calculated from calibration curve. 9) % Practical yield: The percentage of production yield was calculated from the weight of dried pellets (w1) recovered from each of batches and the sum of the initial dry weight of starting materials (w2). The formula for calculation of percentage yield is as follows. % Practical yield = (practical value/ theoretical value) * ) In-Vitro Dissolution Study: The in vitro dissolution study of 62.5 mg equivalent weight of Bosentan HCl pellets were performed as described in USP type-i apparatus fitted with basket (100 rpm) at 37 o C ± using simulated gastric fluid (ph 1:2 700 ml) as a dissolution medium for first 2 hour and followed by phosphate buffer (ph ml) by adding 200 ml of 0.2 mol/l tri basic sodium phosphate in dissolution media for remaining hours. At the 1 hour time intervals, 10 ml samples were withdrawn, and analyzed at 247 nm in 0.1 N HCl and 247 nm in 6.8 phosphate buffer using a shimadzu UV 1800 double beam spectrophotometer (Shimadzu, Kyoto, Japan) Cumulative percentage drug release was calculated using an equation obtained from a calibration curve which is developed in the range of 2-16 µg/ml for 0.1 N HCl and ph 6.8 phosphate buffer. STABILITY STUDY Stability testing of drug products beings as a part of drug discovery and ends with the demise of the compound or commercial products. To assess the drug and formulation stability, stability studies were done according to ICH guideline Q1C. The stability studies were carried out on the most satisfactory formulation as per ICH guideline Q1C.The optimized formulation (F6) sealed in vial with rubber cap and kept in humidity chamber maintained 40±2 o C/75±5% RH for 1 month. At the end of studies, samples were analysed for the in vitro drug release study. Comparison of both batches was carried out using similarity factor (f2) and disimilarity factor (f1) and t Test: two samples assuming equal variance. 129

7 RESULT AND DISCUSSION Drug polymer compatibility studies The formulation contains Bosentan HCl, and Eudragit RS 100 and Eudragit RL 100. There is no significant difference observed in characteristic peaks of pure drug and drug excipients mixture. So it was indicated that drug was compatible with excipients. 100 %T bosentan HCl /cm Figure 1: FTIR Spectra of Bosentan HCl (Pure drug) Table 4: Frequency of Pure drug Functional group Reference Frequency of pure drug (cm -1 ) Aromatic C-H bond C-N Stretch N-H bend C-H Stretch C-Cl Stretch %T 95 formulation1 bosentan bosentan HCl formulation /cm Figure 2: FTIR Spectra of Bosentan HCl + Formulation 130

8 Table 5: FTIR spectra of pellets formulation Functional group Frequency cm -1 Pure drug Formulation Aromatic C-H bond C-N Stretch N-H bend C-H Stretch C-Cl Stretch Differential Scanning Calorimetry DSC thermogram study was performed for interaction between the drug and polymer. The drug and polymer were closely maintained at same temperature throughout the analysis. The DSC thermogram was showed peak for the drug, individually as well as in combination with polymers, which indicated that there was no significant interaction between the drug and polymers. Table 6: Interpretation of DSC spectral data Name of Substance Bosentan Drug + polymer Eudragit RL 100 Eudragit RS 100 Temperature o C o C o C o C o C o C Figure 3: DSC spectrum of Pure drug Bosentan HCl 131

9 Figure 4: DSC spectrum of Drug+ Formulation Figure 5: DSC spectrum of Eudragit RL 100 Figure 6: DSC spectrum of Eudragit RS

10 Absorbance Research Article CODEN: IJPRNK Impact Factor: ISSN: Analytical Results The calibration curve for bosentan was developed in 0.1 N HCl and phosphate buffer ph 6.8. A plot was obtained in the concentration range of 2-16µg/ml and the absorbance was measured at 247 nm. Table 7: Standard curve of Bosentan HCl in 0.1 N HCl Sr. No Conc. (µg/ ml) Absorbance Calibration curve of Bosentan HCl in 0.1 N HCl y = 0.055x R² = Sr. No Figure 7: Standard curve of Bosentan HCl in 0.1 N HCl at 247nm Table 8: Standard curve of Bosentan HCl in 6.8 ph phosphate buffer Conc. (µg/ml) Concentartion ( µg/ml) Average Absorbance 133

11 Absorbance Research Article CODEN: IJPRNK Impact Factor: ISSN: Calibration curve of Bosentan HCL in 6.8 phosphate buffer Concentration (µg/ml) y = 0.057x R² = Figure 8: Standard Calibration curve of Bosentan HCl in 6.8 ph Phosphate buffer EVALUATION PARAMETER Table 9: Flow properties of factorial batches (F1-F9) of pellets Batch code Bulk density ( g/cm 3 ) Tapped density ( g/cm 3 ) Hausner s Ratio Carr s Index (%) Angle repose (Degree) F1 0.67± ± ± ± ±1.39 F2 0.72± ± ± ± ±0.82 F3 0.65± ± ± ± ±2.12 F4 0.64± ± ± ± ±1.46 F5 0.76± ± ± ± ±1.46 F6 0.62± ± ± ± ±0.75 F7 0.74± ± ± ± ±0.56 F8 0.66± ± ± ± ±0.57 F9 0.70± ± ± ± ±1.87 of 134

12 Table 10: Evaluation Factorial batches (F1-F9) of pellets Batch code % yield of % Drug loading % friability Mean particle Size pellets (µm) F F F F F F F F F Table 11: In Vitro drug release studies of Factorial batches TIME (Hour) %CPR F1 F2 F3 F4 F5 F6 F7 F8 F In the factorial batches, different ratio Eudragit RS 100 and Eudragit RL 100 were used. In Vitro drug release profiles of the factorial batches are reported in the Table.11and Figure No.9. Results specify that drug release time was increased with increase the polymer concentration. In Vitro drug release profile of the factorial batches indicated that F1 batch shows 96.1 % drug release within 10 hour while F2 batches shows 97.4% drug release within 11 hour, F3 batch shows 96.9 % drug release within 12 hour, F4 batch shows 89.2% drug release within 10 hour, F5 batch shows 99.7% drug release within 11 hour, F6 batch shows 99.1% drug release within 12 hour, F7 batch shows 95.7% drug release within 12 hour, F8 batch shows 94.5% drug release within 12 hour, F9 batch shows 93.4% drug release within 12 hour. 135

13 % CPR Research Article CODEN: IJPRNK Impact Factor: ISSN: F1 - F9 batches Time (hour) F1 F2 F3 F4 F5 F6 F7 Figure 9: In vitro dissolution of F1-F9 batches RESPONSE SURFACE PLOT In the factorial design and different graphical representation of pellets were prepared using different ratio of polymer is X1 is a Eudragit RS 100 and X2 is Eudragit RL 100 was affected on t50(hr), t90(hr), Q2 (%), Q10 (%). As increase in concentration of Eudragit RS 100 and Eudragit RL 100, increase in t50 (hr) and Q2 (%) but decrease in t90 (hr) and Q10 (%). From the result of factorial batches (F1 F9), it can be reported that F6 batch (15% Eudragit RS 100 and 12.5 % Eudragit RL 100). Figure 10: Response surface plot of t50 136

14 Figure 11: Response surface plot of Q2 Figure 12: Response surface plot of t90 Figure 13: Response surface plot of Q10 137

15 KINETIC MODELING OF DISSOLUTION DATA The kinetics of the dissolution data were well fitted to zero order, Higuchi model and Korsemeyer Peppas model as evident from regression coefficients. The value of diffusion exponent (n) for F1 to F9 batches of factorial formulations were between to so it indicates fickian diffusion of the drug from formulation which corresponds to diffusion, erosion and swelling mechanism. Kinetic model Higuchi model shows that R 2 value F1 F9 batches were in range between to shows that drug release type was diffusion type from gel network and sustained drug release for longer period of time. Kinetic model zero order representing that R 2 value of F1 F9 batches were range in between to that near about clearly mentioned that drug release from stiff gel networking was zero order drug release that not depends on concentration of drug. Kinetic model first order shows that R 2 value of F1 F9 batches were in range between to which was less than the R 2 value of zero order drug release therefore the drug release type was dominant to zero order release from gel network which is reported in Table.12. Table 12: Kinetic modeling of dissolution data F1 F2 F3 F4 F5 F6 F7 F8 F9 Zero order S I R First order S I R Higuchi S I R Hixon Crowell S I R Korsemeyer and Peppas N I R S=slope, I=intercept, R 2 =square of correlation coefficient, n=diffusion exponent 138

16 COMPARISON OF DISSOLUTION PROFILES FOR SELECTION OF OPTIMUM BATCH The values of Dissimilarity factor (f1) and similarity factor (f2) for all batches were compared with theoretical dissolution profile (Table 5.22). it was indicated that F6 batch shows minimum value of f1 (3.58) and also showed maximum value of f2 (80.15). So it was revealed that F6 batch having less dissimilarity and good similarity with theoretical release profile. Table 13: Similarity factor (f2) and Dissimilarity (f1) of F1-F9 Batch Similarity factor (f2) Dissimilarity factor (f1) F F F F F F F F F Verification of model by check point batch Time (hour) CPR (%) Table 14: Dissolution of check point batch 139

17 Table 15: Evaluation parameter and in vitro dissolution of check point batch In vitro dissolution study Check t50 t90 Q2 Q10 point P O P O P O P O batch It can be observed that the predicted value and observed value of CP t50, t90, Q2, Q10 of SR pellets were nearly similar with 3 2 factorial design batches. It can be revealed that the evolved model can be used for prediction of response i.e. In vitro dissolution time of pellets within the simplex space. Here comparative analysis of the predicted value and experimental value using paired t test was carried out. It was shows that there was no significant difference between tcal (1.23) and ttab (3.18). Hence it complies the t test because of ttab values was higher than tcal. In the present research work, no more difference between factorial batches and one check point composition. ACCELERATED STABILITY STUDY Amongst all the nine batches, pellets of batch F6 have more desirable characteristics as the pellets of batch F6 gave about 99.1 % of drug release in 12 hrs. Having Q2 value of 41.8% drug release in 2 hrs and Q10 value of 93.1% drug release in 10 hrs showing sustained release formulation. Hence the pellets batch F6 have considered as promising batch for accelerated stability study. From results of accelerated stability study, it was observed that the pellets of batch F6 was stable for period of 1 month at 40 o C/75%RH. The f1 value found was (3.58) and f2 value found was (80.15) respectively for dissolution profile of pellets after 30 days of storage comparing with the dissolution profile of freshly prepared formulation. The f1 and f2 Value was in range of 0-15 and respectively indicating similarity between two dissolution profiles. Table 16: In vitro dissolution data of F6 batch after accelerated stability study Time (hrs) CPR CPR (After 30 days) Time (hrs) CPR CPR (After 30 days)

18 CONCLUSION In the Present Research work, attempt has been made to formulation and evaluation of Sustained Release Pellets Bosentan HCl. FTIR spectroscopy revealed that there was no chemical interaction between drug and polymer so; drug is compatible with polymer. DSC thermogram study was performed for interaction between the drug and polymer. It was showed peak for the drug, individually as well as in combination with polymers, which indicated that there was no significant interaction between the drug and polymers. As increase in concentration of Eudragit RS 100 and Eudragit RL 100, increase in t50 (hr) and Q2 (%) but decrease in t90 (hr) and Q10 (%). From the result of factorial batches (F1 F9), it can be reported that F6 batch (15% Eudragit RS 100 and 12.5 % Eudragit RL 100) shows 99.1% drug release at 12 hours. Comparative analysis of the predicted value and experimental value using t test revealed that there was no significant difference between the two values thereby establishing validity of generated mode of in vitro dissolution time of pellets with one check point composition. Various kinetic models confirmed that In vitro release kinetic of optimize batch (F6) was followed diffusion and erosion mechanism and n value indicates non fickian behaviour with mixed order drug release pattern. Finally, we can conclude that formulation and evaluation of sustained release pellets was successfully completed so, It will be used for the large scale production. REFERENCE 1. Patidar S and Chauhan BP, Oral sustained release dosage form: A Review. J. of drug discovery and therapeutic. 2013, 1(12), Chugh I, Seth N, Rana AC, Gupta S, A Review On: Oral Sustained Release Drug Delivery. Int. Res. J.Pharm. 2012, 3(5), Bhargava A, Rathore RSP, Tanwar YS, Gupta S, Bhaduka G, Oral Sustained Release Dosage Form: An Opportunity to Prolong the Release of Drug. Int J. Advanced Res. Pharm. Bio. Sci Gupta MM and Ray B, A Review on: Sustained release technology. Int. J. of therapeutic application, 2012, 8, Costa P, Manuel J and Labao S, Modeling and Comparison of dissolution profiles. Euro. J. Pharm. Sci. 2002, 13,

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