By Atul A. Bodkhe, Prashant Zurao, A. V. Chandewar, S. B. Jaiswal
Venlafaxine is a unique antidepressant that differs structurally from other currently available antidepressants. Sustained release tablets of venlafaxine to be taken once daily were formulated with venlafaxine hydrochloride equivalent to 37.5 mg of venlafaxine base. Matrix system based on non swellable polymers was selected for sustaining the drug release. Different polymers and waxes viz. hydroxypropylmethylcellulose (HPMC), stearic acid, cetyl alcohol, ethyl cellulose etc. were studied. Combinations of non-swellable waxes with HPMC were also tried in order to get the desired sustained release profile over a period of 24 h. The effect of drug to wax ratio on in vitro release was studied. The marketed formulation was evaluated for different parameters such as appearance, weight variation, drug content and in vitro drug release. The optimized formulation was subjected to stability studies at 40oC/70% RH. These were evaluated for appearance, weight variation, thickness, hardness, friability, drug content and in vitro drug release at selected time intervals.
Key Words : Venlafaxine, matrix system, cetyl alcohol, stearic acid, ethyl cellulose.
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