Physicochemical investigation of the interaction between cellulose derivatives and plasticizers in controlled release forms: Application to spray-dried acetaminophen microparticulate systems

Various analytical methods have been used to investigate the effects of spr ay-drying on acetaminophen, cellulose derivatives and some additives and th e possible interactions between the components. The results obtained indica te that the active compound is not modified during spray-drying; no polymor phism occurs. Moreover, acetaminophen does not interact with the excipients used in the fabrication of the microparticles. Conversely, interactions we re observed between two plasticizers (tartaric and oxalic acids) and sodium carboxymethyl cellulose. They consist in ion-exchange and result in a modi fication of the film properties. They promote the formation of a more effec tive drug coating, which helps to retard drug release.