Formación de complejos fármaco-resina usados en preparados de liberación prolongada

time intervals required for reaching the proper balance of ion exchange reactions during the formation of polystirene-dyvinil-benzene-sulphonate complex salts with drugs such as dexamphetamina, metylhomatropine and salbutamol are analyzed. drug salt solutions were caused to react with resin in "sodium" form, then supernadant concentration was estimated at intervals following the development of the reaction and determining the point of balance. a simple statistical method which makes it possible to determine the time when the reaction shall be finished was proposed, and also values lower than those reported in literature were found. some comment on the association between molecular dimension and the saturation level of the drug-resine complex are made