Design and Development of Controlled Porosity Osmotic Pump Tablets of Zidovudine Using Sodium Chloride as Osmogen for the Treatment of Aids

Abstract

Chinmaya keshari sahoo, Nalini kanta Sahoo, Surepalli Ram Mohan Rao, Muvvala Sudhakar

The present study investigates the feasibility of the design and develops controlled porosity osmotic pump (CPOP) tablets to prolong the drug release of an antiretroviral drug zidovudine of 600mg once daily. Five formulations (ZS1to ZD5) were prepared by wet granulation method using various excipients. The CPOP consisted of an osmotic core coated with a micro porous membrane made up of cellulose acetate, poly ethylene glycol and sorbitol as in situ micro pore former. The prepared tablets were evaluated for pre compression parameters, post compression parameters, in vitro drug release study, Fourier Transform Infrared Spectroscopy (FTIR) study, Differential Scanning Calorimetry (DSC) study and scanning electron microscopy (SEM) study. The formulation variables such as effect of osmogen concentration, effect of pore former concentration, effect of membrane thickness of semi permeable membrane were evaluated for drug release characteristics. For the optimized formulation (ZS4) effect of osmotic pressure, effect of pH and effect of agitation intensity was evaluated. The in vitro release kinetics were analyzed for different batches by different pharmacokinetic models such as zero order, first order, Higuchi, Korsmeyer-Peppas and Hixson-Crowell model. The result of optimized formulation releases drug up to 16 hrs in a controlled manner and follows Higuchi kinetics and which is independent of the pH and agitation intensity. The optimized formulation was found to be stable up to 3 months when tested for stability study at 40±2ºC/ 75±5% RH

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