Study on the Absorption and Excretion of Capsaicin in Rabbits

가토에 있어서 Capsaicin의 흡수 및 배설에 관한 연구

Quantitative determination of capsaicin in biological fluid was investigated. The pharmacokinetic study of capsaicin in rabbits was performed by high-pressure liquid chromatography, equipped with a microparticulate reversed-phase column and a fixed wavelength detector. Elution was carried out using methanolwater(70:30). It allows the quantitative determination at 8-400 ng level. When single dose of capsaicin(4mg/kg) was given to rabbits intravenously, the elimination phase was extremely short with average half-life to 17.35 minute. Urine excretion of capsaicin itself during first 2 hours after intravenous administration (4mg/kg) was 0.004-0.04% of the administered amount. The maximum plasma concentration of capsaicin after oral administration (300mg/kg) was $4{\times}10^{-7}$g/ml at 40 minutes. The $LD_{50}$ of capsaicin in mouse was 0.40mg/kg (i.v.) and 47.2 mg/kg (p.o.) which was determined by Litchfield and Wilcoxon's method, suggesting that the gastrointestinal absorption of capsaicin is poor.