Madhavan V

Drug release retarding polymers are the key performers in sustained release drug delivery system for which various natural, semi-synthetic and synthetic polymers have been investigated. The use of natural polymers over synthetic has gained importance due to their biodegradable, biocompatible, cost effectiveness and safety considerations. The present study deals with isolation of mucuna gum from the species of Mucuna flagillepes (Papillionaceae) and evaluating its suitability as a microencapsulating agent for delivery of propranolol hydrochloride. The gum was extracted from mucuna seeds by using 1% sodium-meta bisulphite as solvent followed by precipitation with acetone. The extracted gum was evaluated for physical characteristics like melting point, solubility, pH, total ash and micromeritic properties. Propranolol hydrochloride, a non selective beta-adrenergic receptor blocking agent was chosen as a model drug for formulation of microspheres with different drug: polymer [1:1-2.5] ratios by emulsification solvent evaporation method. The microspheres were evaluated for yield, particle size, drug loading efficiency and in-vitro drug release studies. The drug-polymer compatibility was confirmed by IR spectroscopy. The yield of formulations was found to be between 79 to 90.3% with the average particle size between 55.8 to 74.5µm.The drug encapsulation efficiency of microspheres was found to be in the range of 67.7 to 89.9%. The in-vitro drug release studies revealed that the polymer had positive effect on the drug retarding efficiency. The selected microspheres showed sustained and complete drug release up to 12 hours. Thus mucuna gum as a natural biodegradable polymer proved to be a suitable drug release encapsulate.

One of the most feasible approaches for achieving a prolonged and predictable drug delivery profiles in the GIT is to control the gastric residence time (GRT) using gastroretentive dosage forms. The aim of the present study is to prepare the floating microspheres of ketoprofen to sustain the drug release for longer time to overcome the short half life of the drug. The microspheres were prepared by emulsification-solvent evaporation technique using ethyl cellulose and heat denaturation technique using egg albumin as a natural polymer. The optimization of microspheres was carried out based on pentagonal design using response surface methodology. The floating microspheres were evaluated for micromeritic properties, particle size, percentage yield, in-vitro buoyancy, entrapment efficiency, drug polymer compatibility, scanning electron microscopy and in-vitro drug release studies. The prepared microspheres exhibited prolonged drug release (> 9 h) and remained buoyant for > 24 h. The mean particle size increased and the drug release rate decreased at higher polymer concentration. The optimized formulation of ethyl cellulose microspheres (KEC-OP) exhibited prolonged drug release of 88.31 % up to 10 h demonstrating zero order kinetics and Case II transport release mechanism where as optimized formulation of egg albumin (KEA-OP) showed drug release of 96.78 % up to 9 h demonstrating peppas kinetics and Case II transport release mechanism.