Host - guest System of Zofenopril and Randomly Methylated β - cyclodextrin Preparation, characterization and solubility

Zofenopril calcium (ZOF) is one of the newest angiotensin converting enzyme (ACE) inhibitor, highly lipophilic and with low water solubility. This research investigates the interaction between ZOF and randomly methylated β-cyclodextrin (RAMEB), in order to prove the formation of an inclusion complex that has an enhanced water solubility profile for ZOF. This paper reports, for the first time, the physicochemical characterization and the solubility profile of an inclusion complex between ZOF and RAMEB, which is prepared using the kneading method. Different spectroscopic techniques, namely powder X-ray diffraction, ATR FT-IR spectroscopy, were applied in order to prove the formation of the ZOF/RAMEB inclusion complex, both in water and in solid state. The complex formation is further backed by thermal analysis (TGA/DTG/HF). The obtained results confirm that the physicochemical properties of the ZOF/RAMEB 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 RAMEB, the solubility test has indicated that the water solubility of ZOF was increased by 4 times.