RP-HPLC-UV method coupled with post-column iodine-azide reaction for determination of free captopril in urine samples.
BACKGROUND
A free urinary captopril is measured indirectly employing the iodine-azide reaction in post-column mode. The pre-clean-up and/or derivatization step is needless, so that the method is adequate for rapid captopril determination in the urine samples and its monitoring at clinical trial. Captopril is separated on a C4 column by the eluate composed of sodium azide solution (4% [w/v], pH 5.8), acetonitrile and water at a ratio of 50:5:45 (v/v/v). The linearity exists in the range from 0.06 to 2.25 µmol/ml of urine. LOD and LOQ receive 0.03 and 0.06 µmol/ml of urine, respectively.


RESULTS
Inter-day precision and accuracy of measurements of the captopril-spiked urine samples were 9, 8 and 5%, and 104, 107 and 105%, respectively, for 0.060 (low level), 0.50 (medium level) and 1.25 (high level) µmol/ml of urine.


CONCLUSIONS
Captopril content was determined in real urine samples delivered from patients treated with this drug.
Department of Inorganic & Analytical Chemistry, Faculty of Chemistry, University of Łódź, 12 Tamka St, 91-403 Łódź, Poland.
Adam
A
Łuczak
Robert
R
Zakrzewski
Miłosz
M
Dobrogowski
D000097:Acetonitriles; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use / Q000652:urine*; D002216:Captopril / Q000627:therapeutic use / Q000652:urine*; D056148:Chromatography, Reverse-Phase / Q000295:instrumentation / Q000379:methods*; D004355:Drug Stability; D004867:Equipment Design; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D007455:Iodine / Q000737:chemistry; D057230:Limit of Detection; D016014:Linear Models; D012015:Reference Standards; D019810:Sodium Azide / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*
D000097:Acetonitriles; D000806:Angiotensin-Converting Enzyme Inhibitors; D007455:Iodine; D019810:Sodium Azide; D002216:Captopril; C032159:acetonitrile