ABSTRACT
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