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RP-HPLC-UV method coupled with post-column iodine-azide reaction for determination of free captopril in urine samples
Adam Łuczak1, Robert Zakrzewski, Miłosz Dobrogowski
1Department of Inorganic & Analytical Chemistry, Faculty of Chemistry, University of Łódź, 12 Tamka St, 91-403 Łódź, Poland.
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.
Conclusion:
Captopril content was determined in real urine samples delivered from patients treated with this drug.
