FORMULATION DESIGN AND EVALUATION OF MUCOADHESIVE BUCCAL TABLETS OF NITROGLYCERIN Original Article BALAGANI PAVAN KUMAR a* , PALLEPATI KAVITHA b , KATAMREDDY JYOTHSHNA DEVI a a* Department of Pharmaceutics, Gokula Krishna College of Pharmacy, Sullurpet-524121, A.P, India, b Received: 10 Apr 2014 Revised and Accepted: 15 May 2014 Department of Pharmaceutics,Gokula Krishna College of Pharmacy, Sullurpet-524121, A.P, India. Email: pavan.gkcp@rediffmail.com ABSTRACT Objective: The main objective of present investigation is to prolong drug action and enhance bioavailability. Methods: The tablets were prepared using Carbopol 934 in varying concentration with secondary polymers like HPMC K4M, HPMC K15M and sodium alginate by direct compression method. The compatibility studies like TLC and FTIR spectroscopy were carried out. The tablets were evaluated for hardness, thickness, weight variation, friability and drug content and concluded that all these parameters were in acceptable range of pharmacopoeial specification. The tablets were furtherevaluated for their mucoadhesive characteristics such as surface pH, swelling index, ex vivo residence time, mucoadhesive strength, ex vivo permeation,in vitro drug release and also for the effect of Carbopol concentration on mucoadhesive parameters. Results: The surface pH of the tablet was 6.48 to 6.75 which fall in the range of salivary pH and all the tablet of batch C containing sodium alginate as secondary polymer showed ex vivo residence time of 10 to 12.30 hrs indicated good mucoadhesive capacity of tablet. The buccal tablets showed good swelling up to 8 hrs maintaining the integrity of polymers. The formulation (C3) showed better control of drug release and able to release entire amount of drug in 12 hrs than the other formulations. All the formulations of batch C & A except A1 followed zero order kinetics and all other formulations of batch B and A1 formulation followed Hixson-Crowell model.The ‘n’ value of all the formulations was found to be more than 0.89 indicating that the drug release followed Super case II transport type of release mechanism due to the erosion of the polymer. All the tablets showed good mucoadhesive strength in the range of 21.87 to 26.26.Ex vivopermeation studies of the optimized formulation C3 revealed that percent drug permeated through sheep buccal mucosa was 38.294 % for 8 hrs. The slopes of the basic in vitro data suggests that drug permeates across the membrane but slowly as the mucosa offers barrier to the transportation of the drug. Conclusion: Hence Carbopol 934 and Sodium alginate polymers can be used to prepare mucoadhesive buccal tablets of nitroglycerin having prolonged therapeutic effect with enhanced bioavailability. Keywords: Nitroglycerin, Swelling index, In vitro drug release. Mucoadhesion, Ex vivo permeation. INTRODUCTION Buccal drug delivery [1-3] has gained significant attention and momentum since it offers remarkable advantages. Over past few decades, buccal route for systemic drug delivery using mucoadhesive polymers to significantly improve the performance of many drugs has been of profound interest. Administration of compounds via the mucosa of the oral cavity avoids pre-systemic metabolism in the gastrointestinal (GI) tract and hepatic first pass elimination. In addition, the buccal mucosa is a well-vascularised tissue and is easily accessible for both application and removal of a delivery device. It’s having facility to include permeation enhancer/enzyme inhibitor or pH-modifier in the formulation and versatility in designing as multidirectional or unidirectional release systems for local or systemic action, etc. Buccal drug delivery systems is a promising area for continued research with the aim of systemic delivery of orally inefficient drugs as well as a feasible and attractive alternative for non-invasive delivery of potent peptide and protein drug molecules. Nitroglycerin[4-5]is a vasodilator used in treatment of angina. It is well absorbed from the oral cavity and has low molecular weight, which favours its administration through buccal route. The objective of this research was to formulate and evaluate mucoadhesive buccal tablet containing nitroglycerin to prolong therapeutic effect, increase bioavailability of the drug and reduce the dosing frequency.In the present investigation mucoadhesive polymers [6-7] like Carbopol 934p, HPMC K4M, HPMC K15M and Sodium alginate were used to prepare mucoadhesive buccal tablets by employing direct compression technique. The prepared buccal tablets are subjected to evaluated for physicochemical properties and release characteristics MATERIALS AND METHODS Nitroglycerin was obtained as gift sample from Shasun pharmaceuticals Ltd, Pondicherry. Carbopol 934, Sodium alginate, Lactose and Talc were purchased from S.D. Fine – Chem. Ltd, Mumbai. HPMC K4M and HPMC K15M were purchased from Colorcon Asia Pvt. Ltd, Goa. The chemical reagents used were of analytical grade. Drug – Excipient compatibility studies Drug – Excipient compatibility study by Thin Layer Chromatography In this method drug and excipients in 1:2 ratio were mixed and analyzed for compatibility by using TLC after one, two, three and four weeks. 10µl of reference and test solutions were applied as spots on the dry activated plate. The solvent system was allowed to run up to desired height; the plates were removed and allowed to dry. The dry plates were then exposed to iodine vapors in a chamber to observe the spots. The plates were then removed and the Rƒ Drug – Excipient compatibility study by Fourier Transform Infrared Spectroscopy (FTIR) values calculated. The details of chromatographic conditions were shown in Table no. 1. The pure drug and optimized formulations were subjected for FTIR analysis. The samples were scanned over a range of 4000-400 cm -1 using Fourier transformer infrared spectrophotometer. Spectra’s were analyzed for drug polymer interactions. International Journal of Pharmacy and Pharmaceutical Sciences ISSN- 0975-1491 Vol 6, Issue 7, 2014 Innovare Academic Sciences