title: High-performance liquid chromatographic assay of tolbutamide and carboxytolbutamide in human plasma.
abstract: A high-performance liquid chromatographic method was developed for the simultaneous measurement of tolbutamide and its major metabolite, carboxytolbutamide, in plasma. The assay involves the ether extraction of 1 ml of plasma, using chlorpropamide and an internal standard. The extract is dried, the residue is taken up in acetonitrile, and 5 micro l is injected into a reversed-phase column. The mobile phase consisted of 35% acetonitrile and 65% 0.05 M phosphoric acid buffer (pH 3.9). A fixed-wavelength detector was set at 254 nm. The sensitivity limits for the tolbutamide and carboxytolbutamide assay were 2 and 0.1 microgram/ml, respectively. The ratio of carboxytolbutamide to tolbutamide in plasma obtained from a subject given a 500-mg tolbutamide tablet was 1:20.
mesh_terms: D002747:Chlorpropamide / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004355:Drug Stability; D006801:Humans; D013056:Spectrophotometry, Ultraviolet; D014044:Tolbutamide / Q000031:analogs & derivatives* / Q000097:blood*
chemical_list: C006913:carboxytolbutamide; D014044:Tolbutamide; D002747:Chlorpropamide