Cyclodextrin inclusion complex of a multi-component natural product by hot-melt extrusion

Abstract

This study aimed to investigate whether hot-melt extrusion (HME) processing can promote molecular encapsulation of a multi-component natural product composed of volatile and pungent hydrophobic substances (ginger oleoresin, OR) with cyclodextrins. 6-gingerol and 6-shogaol, the biomarkers of ginger OR, were quantified by HPLC. Phase-solubility studies were performed using β-cyclodextrin (βCD) and hydroxypropyl-β-cyclodextrin (HPβCD) for ginger OR complexation. Solid complexes were then prepared by thermal (HME) and solvent (slurry, SL)-based methods. Morphology, thermal behavior, solubility, in vitro dissolution, and in vivo anti-inflammatory activity were evaluated. HPβCD gave rise to AL-type complexes with ginger OR, whereas βCD led to materials with limited solubility. Ginger OR was complexed with HPβCD by HME without significant change in gingerol and shogaol content. Additionally, TGA suggested higher volatile retention in HME complexes than SL ones. Shogaol and gingerol solubility and dissolution significantly increased from SL and HME complexes compared with ginger OR. In turn, 1: 2 OR/HPβCD HME complex showed higher 6-shogaol solubility than SL, associated with a gradual release. The carrageenan-induced pleurisy test showed that the anti-inflammatory activity of ginger OR was maintained after complexation with HPβCD. The complexes significantly decrease the levels of IL-1β and inhibit cell migration. HME complex showed performance equivalent to the positive control and superior to the SL material. Taken together, these results indicate that HME can be useful for promoting the molecular encapsulation of complex natural products that contain volatile and thermolabile substances. HME complexes showed better in vivo and in vitro performance than complexes prepared using the solvent-based method.