Investigation of inclusion complex of honokiol with sulfobutyl ether-β-cyclodextrin

This study aimed to prepare and characterize an inclusion complex of honokiol (HNK) with sulfobutyl ether-β-cyclodextrin (SB-β-CD). The inclusion complex (HNK/CD COMP) was prepared utilizing a freeze–drying method. Phase-solubility curves were employed to obtain stability constants and thermodynamic parameters. The phase-solubility diagram showed a typical AL-type, indicating that the 1:1 (HNK:SB-β-CD) inclusion complex was formed. The solid inclusion complex was then characterized by differential scanning calorimetry and Fourier transform infrared spectroscopy. Results showed that HNK/CD COMP exhibited a higher drug release rate than free HNK in vitro. A comparative study of the pharmacokinetics between HNK/CD COMP and free HNK was also performed in rats. In vivo results indicated that AUC0–t and Cmax of HNK/CD COMP increased by approximately 158% and 123% compared with those of the free HNK, respectively. These results suggest that SB-β-CD will be potentially useful in the delivery of poorly soluble drugs, such as HNK.