Effect of processing variables of spray drying technique on physical properties of controlled release theophylline matrices

Abstract

Manufacture of controlled release theophylline matrices using spray drying process was studied. The influences of processing variables including the inlet air temperature, the feed rate of the spray drying solution, the atomizing air pressure and the concentration of feed solution on physical properties of the spray dried powders and on the release characteristics of the resultant matrices were investigated. This technique provided uniform distribution of drug in spray dried products which were not affected by processing variables used. The dissolution behaviors of matrices were not sensitive to processing variables except the inlet air temperature in the drying chamber and at the high concentration of solution (25%). With an increase in inlet air temperature, there was a reduction in drug release rate. The effect of tableting process on release pattern of the spray dried matrices was also studied. Variation of compressional force during tableting did not remarkably alter the drug release of the matrices. This process offered good reproducibility of drug release rate from matrices of different production batches.