In vitro Release Kinetic Study of Theophylline from Eudragit RS PO and Eudragit RL PO Matrix Tablets

The aim of the present study was to investigate the release kinetics of theophylline from permeable acrylic polymer matrix tablets. Matrix tablets were prepared by direct compression method using Eudragit RS PO and Eudragit RL PO. Two batches of matrix tablets were prepared. Only Eudragit RS PO was used in the first batch, and in the second batch both Eudragit RS PO and Eudragit RL PO were used as the rate retarding polymers in different proportions. The variation of hardness was insignificant in batches. Drug release was investigated by using USP basket method and the results of release rates were analyzed by using correlation coefficient value of Zero order release plot & Higuchi plot and exponent value of Bi-exponential release profile. Theophylline tablets having only Eudragit RS PO showed comparatively slow release but release rate improved significantly as seen in formulations containing Eudragit RL PO and Eudragit RS PO. It was also revealed that, in all cases the release of theophylline followed mixed release kinetics where Zero order release kinetics was predominant. Key words: Sustained release; matrix tablet; theophylline; acrylic polymers; eudragit; release rate; dissolution; hardness. DOI: 10.3329/dujps.v8i1.5328 Dhaka Univ. J. Pharm. Sci. 8(1): 1-6, 2009 (June)