Inclusion Complex of Chrysin with Hydroxypropyl-β-cyclodextrin (HP-β-CD) Preparation, Characterization, and Dissolution Study

The objective of the study was to prepare and characterize the inclusion complex of chrysin (CHR) with hydroxypropyl-β-cyclodextrin (HP-β-CD). The phase solubility study was performed to reveal supramolecular drug-ligand interactions between CHR with HP-β-CD. CHR/HP-β-CD inclusion complex was prepared using kneading, physical mixture, and coprecipitation method. Physicochemical characterization was performed using FTIR analysis, TGA, SEM, and 1H NMR analysis for CHR, HP-β-CD, and physical mixture (PM). A USP II dissolving test apparatus was utilized to determine the degree of solubility of both pure CHR and CHR/HP-β-CD complex. Results showed that increases in both CHR and HP-β-CD concentrations were directly proportional to increases in the complex’s formation indicating perfect 1:1 stoichiometry. FTIR study showed that because of poly-hydroxyl activity of CHR/HP-β-CD inclusion complex. TGA analysis showed that sharpening of the endothermic peak at 287.69 °C was indicative of CHR melting. SEM analysis revealed that different sized plate-like clusters of crystals were seen in CHR, while amorphous shrinking thread-like particles were seen in HP-β-CD. CHR/HP-β-D inclusion complex displayed a uniform amorphous structure and no evidence of the typical plate-shaped CHR crystal. The presence of CHR causes chemical shifts of the H3 and H5 protons of HP-β-CD to differ significantly from those of the other protons. In vitro dissolution release study exhibited majority of the drug (62.5%) was found to be released within the first 20 min. The stabilizing effect of HP-β-CD was slightly attenuated in the alkaline media. The results showed that the resulting compound was more stable in water under physiologically relevant conditions. It can be concluded from the study that HP-β-CD is preferable to overcome the CHR’s low aqueous solubility.