title: HPLC determination of glutathione and L-cysteine in pharmaceuticals after derivatization with ethacrynic acid.
abstract: Ethacrynic acid and its methyl ester are proposed as useful pre-chromatographic derivatization reagents for the HPLC analysis (UV detection) of reduced glutathione (GSH) and L-cysteine. The optimum experimental conditions for the thiol derivatization, the removal of the excess reagent by liquid-liquid or solid-phase extraction and the reversed-phase chromatographic separations of the thiol adducts were investigated. The method was applied to the HPLC determination of GSH and L-cysteine in commercial formulations and proved to be suitable for the HPLC determination of oxidized glutathione (GSSG) after reduction to GSH using dithiothreitol (DTT).
authors.affiliation: Dipartimento di Scienze Farmaceutiche, Università di Bologna, Italy.
authors.forename: A M
authors.initials: AM
authors.lastname: Di Pietra
authors.forename: R
authors.initials: R
authors.lastname: Gotti
authors.forename: D
authors.initials: D
authors.lastname: Bonazzi
authors.forename: V
authors.initials: V
authors.lastname: Andrisano
authors.forename: V
authors.initials: V
authors.lastname: Cavrini
mesh_terms: D002138:Calibration; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000032:analysis*; D004229:Dithiothreitol / Q000737:chemistry; D004976:Ethacrynic Acid / Q000737:chemistry*; D005978:Glutathione / Q000032:analysis*; D010084:Oxidation-Reduction; D011208:Powders; D013237:Stereoisomerism; D013607:Tablets
chemical_list: D011208:Powders; D013607:Tablets; D005978:Glutathione; D003545:Cysteine; D004976:Ethacrynic Acid; D004229:Dithiothreitol