Physicochemical characterization of zofenopril inclusion complex with hydroxypropyl-β-cyclodextrin

Zofenopril calcium (ZOF)is one of the newest angiotensin converting enzyme (ACE) inhibitor, is one of the highly lipophilic newest angiotensin and with low water solubility. This research investigates the interaction between ZOF and a β-cyclodextrin chemically modified derivative, 2-hydroxypropyl-β-cyclodextrin (HPBCD), in order to prove the formation of an inclusion complex with an enhanced water solubility profile of ZOF. In this research is reported for the first time the physicochemical characterization and the solubility profile of an inclusion complex between ZOF and HPBCD. Different spectroscopic techniques (UV absorption spectrometry, powder X-ray diffraction, attenuated total reflectance Fourier transform IR spectroscopy) were applied in order to prove the formation of the ZOF/HPBCD inclusion complex, both in water and in solid state, backed by thermal analysis (TGA/DTG/HF). The obtained results confirm that the physicochemical properties of the ZOF/HPBCD binary system, prepared using the kneading method, are different in comparison both with the parent substances and the corresponding physical mixture, thus suggesting that an inclusion complex was formed. After the formation of the inclusion complex with HPBCD, the solubility test indicated that the water solubility of ZOF was increased by 5 times.