Determination of captopril and its mixed disulphides in plasma and urine by high-performance liquid chromatography

Determination of endogenous thiols and thiol drugs in urine by HPLC with ultraviolet detection

“…Among several methods for measurement of captopril in human urine, HPLC has been widely used [77][78][79][80][81]. Hayashi et al [77] reported method which enables determination of captopril and its mixed disulfides in plasma and urine.…”

Recent Advances in Pharmaceutical Chemistry—angiotensin-Converting Enzyme Inhibitors

“…These equilibria and the conditions under which they arise have to be considered in the development of the technique, especially with respect to storage and sample preparation. One way of reducing the possibility of these reactions occurring in situ is to add Nethylmaleimide (h, NEM) to the biological sample once collected (23,26,27,(29)(30)(31)(32)(33).…”

“…As captopril does not possess a suitable chromophore to make it amenable to either ultraviolet or fluorescent detection with HPLC, one approach has been to utilize the maleimide derivatization step to form a derivative which can be separated by HPLC, and measured with ultraviolet (26,27), fluorescence (25) or electrochemical (29) detection. Some of the methods are multi-step, i.e.…”

“…After free captopril has been measured, a reducing agent such as tributylphosphine is added to another aliquot of the sample to reduce the disulphide to captopril, and the sample is anaiysed again for free captopril. Standards are biological specimens spiked with either captopril disulphide or HSA-captopril (26), which are reduced in a similar way to the test sample and analysed for free captopril.…”

Long-Term Plasma Levels and Dose Modulation of Alacepril in Patients with Chronic Renal Failure

“…Captopril exists in both free and protein-combined forms. We measured the total (free plus protein-combined forms) concentration of captopril by high-performance liquid chromatography (25). Plasma levels of captopril were measured 2 h after taking alacepril in the morning.…”