Formulation Development of Venlafaxine Hydrochloride Extended Release Tablet and Invitro Characterizations

Venlafaxine is a unique antidepressant that differs structurally from other currently available antidepressants. Short biological half life, low bioavailabilty and frequent administration of drug led rational for development of extended release formulation of Venlafaxine that releases the drug and maintian the plasma drug concentration for more than 12h.Polymers like Hydroxy propyl methyl cellulose (HPMC) K4M and K00M, Novocoat K100M, xanthan gum, Polyox, Carbopol etc. were selected for sustaining the drug release. The tablets were prepared by direct compression method. In vitro drug release study revealed that Novocoat K100M alone was not able to retard the drug release whereas carobopol has high potential to retard the drug release due to its gelling property. The optimized formulation containing combination of HPMC K100M and Polyox WSR303 showed similar drug release profile as marketed formulation VENTAB XL75. Kinetic modeling of in vitro drug release data was best fitted in KorsmeyerPeppas equation indicates drug releases by mixed mechanism of diffusion and erosion. The optimized formulation was subjected to stability studies at different temperature and humidity conditions as per ICH guidelines.