FORMULATION DESIGN AND EVALUATION OF MUCOADHESIVE BUCCAL TABLETS OF NITROGLYCERIN

摘要

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 vivo permeation 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