Comparative study of drug release profiles of theophylline matrix tablets prepared by melt granulation and coacervation techniques

Abstract

Matrix system is a well-established approach for prolonging the activity of otherwise short acting drugs. The present study compared the release profiles of theophylline matrix tablets prepared by melt granulation and coacervation techniques with conventional theophylline tablets. In order to form matrix tablets by melt granulation, molten carnauba wax at 3 different concentrations was mixed with theophylline powder and stirred continuously with a glass rod. While still hot, the moist mass was pressed through a sieve (aperture size 710 μm) and then allowed to cool in an air-conditioned room at 20^oC. To form tablets by coacervation technique, ethanolic solution of theophylline and acrylate – methacrylate polymer (Eudragit^®RL100/RS100) was formed. Drug and polymer were co-precipitated with normal saline solution. The coacervates were collected, dried at 60 ± 0.5^oC and the dried mass was passed through a sieve (710 μm) to obtain granules. The granules were subjected to micromeritics properties evaluation prior to compression to non – disintegrating matrix tablets. The various matrix tablets were subjected to hardness, disintegration, friability, in vitro dissolution tests and release kinetic studies. Most granules were generally free flowing with angle of repose ≤ 29^o. Maximum release, Amax (90%) was achieved in 1 h 40 min (t_max) for conventional tablets. For the matrix formulations produced by melt granulation, Amax (70%) was achieved in 12 h (t_max); while A_max (90%) was achieved in 11 h with tablets produced by coacervation using Eudragit^®RL100 (20%w/w). R² values of most of the formulations (BF2 to BF8) ranged from 0.9906 to 0.9973 (Higuchi model). Thus controlled release tablets can be produced by melt granulation using carnauba wax since the tablets compared favourably with those produced using well – established synthetic polymer (Eudragit^®).

Journal of Pharmaceutical and Allied Sciences, Vol. 16 No.3 (2019)