Preparation and evaluation of sustained release tablets of Theophylline and ephedrine hydrochloride

ABSTRACT

Compressed tablets were prepared from theophylline and /or ephedrine HCL after mixing with sodium carboxymethylcellulose [Na CMC]. The effect of polymer content in the tablets on release patterns of the studied drugs was examined in vitro. A linear relationship between 150% of tablets [time to release 50% of the drug in vitro] and the ratio of polymer content to drug was found to exist within certain limits. The order of release was determined by fitting the experimental data into a simple semiempirical equation. Tablets containing [10.51.5] theophylline and Na CMC as intra- and extra granular additive showed a linear, zero-order release and achieved 100% release within 10.5 hours. A similar release of ephedrine HCL from tablets with drug to polymer ratio of 12 was observed. Complete release of ephedrine HCL took place within 8 hours. Tablets of theophylline, ephedrine HCL and Na CMC at ratio of 415 showed complete release of both drugs within 7 hours