[6]-Shogaol/ß-CDs inclusion complex: preparation, characterisation, in vivo pharmacokinetics, and in situ intestinal perfusion study.

Aims: The aim was to improve the absorption and bioavailability of [6]-shogaol with ß-cyclodextrin (ß-CD) prior to in vitro and in vivo evaluation. Methods: [6]-Shogaol/ß-CDs inclusion complexes (6-S-ß-CDs) were developed using saturated aqueous solution method and characterised with appropriate techniques. The absorption and bioavailability potential of [6]-shogaol was evaluated via in vivo pharmacokinetics and in situ intestinal perfusion. Results: The results of characterisation showed that 6-S-ß-CDs (drug loading, 7.15%) were successfully formulated. In vitro release study indicated significantly improved [6]-shogaol release. Pharmacokinetic parameters such as Cmax, AUC0-36 h, and oral relative bioavailability (about 685.36%) were substantially enhanced. The in situ intestinal perfusion study revealed that [6]-shogaol was markedly absorbed via passive diffusion in the intestinal segments, and duodenum followed by ileum and jejunum. Conclusions: Cyclodextrin inclusion technology could enhance the intestinal absorption and oral bioavailability of hydrophobic drugs like [6]-shogaol.

Thermal degradation kinetics of all-trans and cis-carotenoids in a light-induced model system.

Thermal degradation kinetics of lutein, zeaxanthin, ß-cryptoxanthin, ß-carotene was studied at 25, 35, and 45°C in a model system. Qualitative and quantitative analyses of all-trans- and cis-carotenoids were conducted using HPLC-DAD-MS technologies. Kinetic and thermodynamic parameters were calculated by non-linear regression. A total of 29 geometrical isomers and four oxidation products were detected, including all-trans-, keto compounds, mono-cis- and di-cis-isomers. Degradations of all-trans-lutein, zeaxanthin, ß-cryptoxanthin, and ß-carotene were described by a first-order kinetic model, with the order of rate constants as kß-carotene>kß-cryptoxanthin>klutein>kzeaxanthin. Activation energies of zeaxanthin, lutein, ß-cryptoxanthin, and ß-carotene were 65.6, 38.9, 33.9, and 8.6kJ/moL, respectively. cis-carotenoids also followed with the first-order kinetic model, but they did not show a defined sequence of degradation rate constants and activation energies at different temperatures. A possible degradation pathway of four carotenoids was identified to better understand the mechanism of carotenoid degradation.