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 objective of this research was to characterize the inter-polymer complexes (IPCs) of Eudragit (Eud) types (Eud RS, Eud L, or Eud E) and Kollidon SR (KSR), and elucidate their effects on the drug release kinetics and mechanism. Different preparation techniques were proposed using spray drying and ultrasonic-assisted anti-solvent techniques. The thermal activity, e.g., glass transition temperature (T_g) and Fourier transform infrared spectroscopy were used to characterize the molecular interaction of these IPCs. Theophylline (THP) was selected as a drug model. The effect on the drug release kinetics and mechanism was the main concern of this study. Depending on the results, the hydrogen bonding formation between polymers was observed by a shifting of OH and carbonyl group vibrations. In addition, the van der Waals interaction was identified by an alteration in the vibrational band around the 1,000-1,500 cm^-1. Meanwhile, the change of physicochemical characteristic was identified by the T_g of IPCs. Eud E-KSR and Eud E-Eud L IPC were unable to control the THP release. Meanwhile, Eud L-KSR IPC and Eud RS-KSR IPC were success to control the THP release, but it was pH dependent and independent, respectively. This study concluded that the IPCs allowed the THP release in a controlled manner based on the IPC characteristics and their interactions. Either positive or negative interactions on the drug release were observed due to native characteristics of polymers. © 2019 Syaiful Choiri et al.