Formulation and evaluation of film coated pulsatile release tablets of Venlafaxine Hydrochloride

Hyma.P*
Scientific and Applied Research Center, Hyderabad, Telangana

A B S T R A C T
Conventional dosage form of venlafaxine HCl has a poor pharmacokinetic profile and shorter half life (5hrs) that necessitates 2-3 times daily dosing. Thus, this study attempts to design and evaluate a chronomodulated pulsatile drug delivery system of venlafaxine by rupturable coating method. The core containing venlafaxine were prepared by direct compression method and then coated sequentially with an inner swelling layer containing superdisintegrants like sodium starch glycollate, crosscaramellose, crosspovidone and an outer rupturable layer consisted of Eudragit L 100 and S-100 and HPMC E-15. Total 12 formulations with different levels of inner swelling layer and outer polymeric layer were prepared and subjected to various processing and formulative parameters were investigated. In vitro drug release and rupture tests were performed using USP paddle method at 50 rpm in 0.1 N HCl and phosphate buffer of pH 6.8. The results show that as the amount of inner swelling layer increases the lag time decreases and as the Eudragit coating level increases the lag time increases and percent water uptake of time dependent pulsatile release system decreases. The presence of an osmotic agent and effervescent agent helped in shortening of lag time. Results of stability study revealed that the developed pulsatile release formulation was stable over a range of temperature and period tested.
Keywords: Pulsatile Drug Delivery, Lagtime, Venlafaxine HCl