Stabilization and control of aspirin release via solid dispersion systems

The objective of this investigation was to prepare more stable controlled release aspirin tablets. This was achieved via incorporation of the drug into solid dispersions using three different carries. The carries selected were stearic acid, sodium stearate and magnesium stearate in different ratios. Solid dispersions were prepared by melting technique. The prepared dispersions were evaluated by various methods viz infrared analysis, X-ray diffraction, thermal analysis and microscopic scanning. The previously prepared solid dispersions were utilized to prepare aspirin tablets. It was found that the release from these tablets was dependent on the drug ratio as well as the matrix type. Aspirin release was found to obey first order kinetics. In addition, the drug release was found to be diffusion controlled at 20%, 40% and 60% drug concentration, while solid dispersions containing 80% drug concentration did not follow Higuchi diffusion model

Studying the effect of surfactant on eudragit RS100 microspheres prepared by solvent evaporation technique

Solvent evaporation technique was used to prepare Eudragit RS100 microspheres containing ibuprofen as an example for acidic drugs. The aqueous phase was 0.1 N HCl containing different concentrations of either cetrimide or dioctyl sodium sulfosuccinate [DOSS] as an antiaggregating agent. It was found that the percent of drug content was equal to theoretical drug content on using 0.25, 0.5 or 1% cetrimide. This may be due to that, cetrimide acts as a good transport barrier for dichloromethane, but not for the drug. At the same time the percent of drug content was markedly decreased on using 1.5% cetrimide. That is may be due to the cetrimide micelle formation. The effect of different concentrations of DOSS on the percent of drug content was also studied