Preparation of Liquisolid Compacts of Diclofenac Sodium and Evaluation of their Release Enahancing and Retarding Properties

Abstract

Numerous methods have been applied to improve drug release of pharmaceuticals, among which the liquisolid technology is a recent and most promising approach. With this technique liquid formulations such as solutions or suspensions of poorly soluble drugs in a non-volatile liquid vehicle are converted into acceptably flowing and compressible powders of desirable release profile. In this study, several liquisolid tablets of diclofenac sodium (DS) containing various concentrations of the liquid medication (52, 60 and 70% w/w) were prepared. The ratio of carrier to coating powder material was varied to be 10, 20, and 30. Propylene glycol (PG), polyethylene glycol 400 (PEG 400) and polysorbate 80 were used as non-volatile solvents. The prepared liquisolid compacts were then evaluated for their drug release profiles. The liquisolid compacts demonstrated considerably higher dissolution rates than marketed tablets. It was also shown that the fraction of molecularly dispersed drug in the liquid medication of the liquisolid compacts was directly proportional to the dissolution rate. Liquisolid compacts prepared to sustain the release of DS showed comparable release profile with the marketed preparation. It was revealed that polysorbate 80 and Eudragit^® RL have important role in sustaining the release of the drug from liquisolid matrices. This study showed that liquisolid technology is a flexible approach to enhance or retard the release of DS from compressed formulations.

Keywords: Diclofenac Sodium, Liquisolid Compact, Drug Release, Dissolution Rate, Sustained Release