Cystine is the primary source material for the synthesis of glutathione.However,the pharmacokinetics and tissue distribution of cystine are largely unknown.A surrogate analyte D_(4)-cystine was employed to generate ca...Cystine is the primary source material for the synthesis of glutathione.However,the pharmacokinetics and tissue distribution of cystine are largely unknown.A surrogate analyte D_(4)-cystine was employed to generate calibration curves for the determination of levels of D_(4)-cystine and endogenous cystine in mice by liquid chromatography-tandem mass spectrometry(LC-MS/MS).Validation assessments proved the sensitivity,specificity and reproducibility of the method with a lower limit of quantification(LLOQ)of 5 ng/mL over 5e5000 ng/mL in plasma.The pharmacokinetics of D_(4)-cystine were evaluated after administering injections and oral solutions,both of which minimally impacted endogenous cystine levels.The absolute bioavailability of cystine was 18.6%,15.1%and 25.6%at doses of 25,50 and 100 mg/kg,respectively.Intravenously injected D_(4)-cystine resulted in dramatically high plasma levels with reduced levels in the brain and liver.Intragastrically administered D_(4)-cystine resulted in high levels in the plasma and stomach with relatively low levels in the lung,kidney,heart and brain.展开更多
基金This study was financially supported by the National Natural Science Foundation of the People's Republic of China(Grant Nos.:81773814 and 81530098)the National Key Special Project of Science and Technology for Innovation Drugs of China(Project No.:2017ZX09301013)the National Key Research and Development Program(Grant No.:2018YFC0807403).
文摘Cystine is the primary source material for the synthesis of glutathione.However,the pharmacokinetics and tissue distribution of cystine are largely unknown.A surrogate analyte D_(4)-cystine was employed to generate calibration curves for the determination of levels of D_(4)-cystine and endogenous cystine in mice by liquid chromatography-tandem mass spectrometry(LC-MS/MS).Validation assessments proved the sensitivity,specificity and reproducibility of the method with a lower limit of quantification(LLOQ)of 5 ng/mL over 5e5000 ng/mL in plasma.The pharmacokinetics of D_(4)-cystine were evaluated after administering injections and oral solutions,both of which minimally impacted endogenous cystine levels.The absolute bioavailability of cystine was 18.6%,15.1%and 25.6%at doses of 25,50 and 100 mg/kg,respectively.Intravenously injected D_(4)-cystine resulted in dramatically high plasma levels with reduced levels in the brain and liver.Intragastrically administered D_(4)-cystine resulted in high levels in the plasma and stomach with relatively low levels in the lung,kidney,heart and brain.
