Formulation and In Vitro Evaluation of Sustained Release Matrix Tablets of Venlafaxine
Sustained release matrix tablets of venlafaxine were formulated using synthetic polymers (ethylcellulose & hydroxypropyl methylcellulose). Six (06) different batches of matrix tablets of venlafaxine (dose 75 mg) were prepared by the wet granulation method. Polymers were used alone or in combination. The physical properties of compressed tablets were evaluated. In vitro release drug studies were performed in phosphate buffer at pH 6.8 over 24 hours. The drug release data fitted well to the First-order (R2 = 0.9725 � 0.9900). The n value obtained for most batches ranged from 0.523 to 0.946 indicates that the drug is released through an anomalous or non�Fickian transport. Results revealed that the combination of ethyl cellulose (EC) and hydroxypropyl methylcellulose produced a sustained effect compared to hydroxypropyl methylcellulose alone. Formulation F6 containing single polymer (EC) showed the highest control over initial burst release, and extended-release of the drug continued up to 16 hours.