Optimization of theophylline release from tablets containing Compritol

The sustained release of theophylline embedded in a Compritol matrix containing varying percentages of potassium chloride, hydroxypropylmethyl cellulose or mannitol was studied. All the formulations produced tablets with good mechanical properties ties. The release rate was found to increase with the increase in the percentage of each of the three additives used in the matrix. Approximately 20% of either potassium chloride or mannitol, as well as 5% hydroxypropylmethyl cellulose, could provide the desired drug release (50% in 6 h) with the tablet remaining intact. It was found that the Higuchi linear square root of time relationship with lag time (model 4) was the best model to describe the drug release kinetics from tablets containing Compritol with different additives. This also indicated that a matrix diffusion controlled mechanism was operative.