Characterization of Eudragit types and Kollidon SR inter-polymer complexes and their effects on the drug release

A novel of polymer combination promotes an increase of the ability for controlling the drug release. The objectiveof this research was to characterize the inter-polymer complexes (IPCs) of Eudragit (Eud) types (Eud RS, Eud L, orEud E) and Kollidon SR (KSR), and elucidate their effects on the drug release kinetics and mechanism. Differentpreparation techniques were proposed using spray drying and ultrasonic-assisted anti-solvent techniques. The thermalactivity, e.g., glass transition temperature (Tg) and Fourier transform infrared spectroscopy were used to characterizethe molecular interaction of these IPCs. Theophylline (THP) was selected as a drug model. The effect on the drugrelease kinetics and mechanism was the main concern of this study. Depending on the results, the hydrogen bondingformation between polymers was observed by a shifting of OH and carbonyl group vibrations. In addition, the van derWaals interaction was identified by an alteration in the vibrational band around the 1,000–1,500 cm−1. Meanwhile, thechange of physicochemical characteristic was identified by the Tg of IPCs. Eud E-KSR and Eud E-Eud L IPC wereunable to control the THP release. Meanwhile, Eud L-KSR IPC and Eud RS-KSR IPC were success to control theTHP release, but it was pH dependent and independent, respectively. This study concluded that the IPCs allowed theTHP release in a controlled manner based on the IPC characteristics and their interactions. Either positive or negativeinteractions on the drug release were observed due to native characteristics of polymers.