Formulation Development and Characterization of Controlled Release Core-in-cup Matrix Tablets of Venlafaxine HCl

Background: Venlafaxine HCl is a selective serotonin reuptake inhibitor, which is given in the treatment of depression. The delivery of the drug at a controlled rate can be of great importance for a prolonged effect. Objective: The objective was to prepare and optimize the controlled release core in a cup matrix tablet of venlafaxine HCl using the combination of hydrophilic and hydrophobic polymers to prolong the effect with rate controlled drug release. Methods: The controlled release core in cup matrix tablets of venlafaxine HCl was prepared using HPMC K5, K4, K15, HCO, IPA, aerosol, magnesium stearate, hydrogenated castor oil and micro crystalline cellulose PVOK-900 using wet granulation technique. Total ten formulations with varying concentrations of polymers were prepared and evaluated for different physicochemical parameters such FTIR analysis for drug identification. In-vitro drug dissolution study was performed to evaluate the amount of drug release in 24 hrs, drug release kinetics study was performed to fit the data in zero order, first order, Hixson-crowell and Higuchi equation to determine the mechanism of drug release and stability studies for 3 months as observed. Results: The results of hardness, thickness, weight variation, friability and drug content study were in an acceptable range for all formulations. Based on the in vitro dissolution profile, formulation F-9was considered to be the optimized, extending the release of 98.32% of drug up to 24 hrs. The data fitting study showed that the optimized formulation followed the zero order release rate kinetics and when compared with the innovator product (flavix XR), showed better drug release profile. Conclusion: The core-in-cup technology has the potential to control the release rate of freely water soluble drugs for single administration per day by optimization with the combined use of hydrophilic and hydrophobic polymers.