Radioimmunoassay of a new angiotensin-converting enzyme inhibitor (perindopril) in human plasma and urine: advantages of coupling anion-exchange column chromatography with radioimmunoassay.
Perindopril (P) is a prodrug whose active metabolite perindoprilat (PT) is an antihypertensive agent which acts by inhibition of angiotensin-converting enzyme (ACE). Anti-PT antiserum was produced in a rabbit immunized against PT that was covalently linked to bovine serum albumin. The radioligand is an iodinated (125I) derivative of PT-glycyltyrosinamide. Both the drug (PT) and the prodrug (P) are assayed in the same sample; PT is assayed as is and P is assayed after quantitative alkaline hydrolysis into PT. Certain data obtained from such assays suggest the occurrence in plasma and urine of a third immunoreactive component. A chromatographic fractionation of samples allowed us to isolate a new immunoreactive metabolite which was further identified as a glucuronide of PT (PT-G). Therefore, the whole assay was carried out as follows: biological samples were fractionated by stepwise chromatography on a anion-exchange resin (the first fraction contained P, the second contained PT, and the third contained PT-G); and RIA was performed on fractions 2 and 3 as is, and on fraction 1 after alkaline hydrolysis. Performances and assessments of this method are presented together with an example of a pharmacokinetic profile.
Doucet
L
L
Immunotech S. A. Case 915, Marseille, France.
De Veyrac
B
B
Delaage
M
M
Cailla
H
H
Bernheim
C
C
Devissaguet
M
M
D000328:Adult; D000918:Antibody Specificity; D000936:Antigen-Antibody Complex; D002852:Chromatography, Ion Exchange; D006801:Humans; D006868:Hydrolysis; D007211:Indoles / Q000032:analysis* / Q000276:immunology / Q000493:pharmacokinetics; D007457:Iodine Radioisotopes; D008297:Male; D020913:Perindopril; D011863:Radioimmunoassay
D000936:Antigen-Antibody Complex; D007211:Indoles; D007457:Iodine Radioisotopes; D020913:Perindopril