Captopril: determination in blood and pharmacokinetics after single oral dose.

The study describes a specific, precise, sensitive and accurate method for determination of unchanged captopril, an angiotensin-converting enzyme inhibitor, in human plasma. Captopril was stabilized by forming an adduct with p-bromophenacyl bromide and this adduct was measured by high-performance liquid chromatography with UV detection. The standard curve was linear over a range of 30-800 ng ml-1. The average yield of derivatization of the unchanged captopril was 73.6% and the recovery of captopril-adduct reached 93.1%. The limit of detection was 15 ng ml-1, while the quantitative limit was 30 ng ml-1. Inter- and intra-assay RSD was below 9%, but inter- and intra-assay accuracy was below 8%. On the basis of elaborated method, a single-dose pharmacokinetics in 12 men, in two doses (25 and 50 mg of captopril) has been investigated. The comparison of the pharmacokinetic parameters obtained from both doses of the drug have been made.