Determination of 1-[5-(2-cyclopropyl-5,7-dimethyl-imidazo[4,5-b] pyridin-3-ylmethyl)thiophen-2-yl]cyclopent-3-enecarboxylic acid (CP-191,166), an angiotensin II antagonist, in dog and rat plasma by high-performance liquid chromatography.
A simple and precise high-performance liquid chromatographic (HPLC) assay was developed and validated for the determination of a novel angiotensin II antagonist, 1-[5-(2-cyclopropyl-5,7-dimethyl-imidazo[4,5-b]pyridin-3-ylmethyl) thiophen-2-yl]cyclopent-3-enecarboxylic acid (CP-191,166, I), in dog and rat plasma. The internal standard (II, a saturated derivative of I) and analyte were extracted by liquid-liquid extraction using methyl tert.-butyl ether. Samples were analyzed by reversed-phase HPLC using a Zorbax C8 narrow-bore column with ultraviolet detection at 289 nm. The quantitation limit of I was 10 ng/ml and the calibration curve was linear over the range of 0.01-10.0 micrograms/ml (r2 > 0.99). In dog and rat plasma, intra- and inter-assay precision ranged from 0.00 to 3.36% and 0.00 to 4.95%, respectively. The average recoveries were similar (73%) for both I and II and the upper limit of quantification of I can be as high as 500 micrograms/ml. The method described has been successfully applied to the quantification of I in about 2000 dog and rat plasma samples over a nine-month period.
Allen
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MC
Drug Metabolism Department, Pfizer Inc., Groton, CT 06340, USA.
Day
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D000804:Angiotensin II / Q000037:antagonists & inhibitors*; D000818:Animals; D000959:Antihypertensive Agents / Q000097:blood* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004285:Dogs; D007093:Imidazoles / Q000097:blood* / Q000493:pharmacokinetics; D011725:Pyridines / Q000097:blood* / Q000493:pharmacokinetics; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013045:Species Specificity; D013056:Spectrophotometry, Ultraviolet
D000959:Antihypertensive Agents; C099503:CP 191166; D007093:Imidazoles; D011725:Pyridines; D000804:Angiotensin II