Comparison of high pressure liquid chromatography and fluorescence polarization immunoassay methods in a XXXX pharmacokinetic study.

@entity2544 @entity101
@entity101 ( @entity101 ) and fluorescence polarization immunoassay (FPIA) were compared in a @entity2544 pharmacokinetic study. Eight healthy subjects received single 600-mg oral doses of two different sustained-release @entity2544 formulations. Fourteen blood samples were collected over 57 h after each dose, and the serum was analyzed for @entity2544 using both @entity101 and FPIA methods. In comparing the two formulations using @entity101 , there was no statistical difference in the area under the curve (AUC), terminal rate constant (k), or time of peak. However, there was a 13% difference in peak @entity2544 concentration (p less than 0.05). The same statistical conclusions were made for all parameters when using FPIA. When comparing the kinetic parameters determined with each assay, the AUC was 12% greater and the k was 17% smaller with FPIA (p less than 0.05). Orthogonal regression of all serum @entity2544 concentrations showed that FPIA = 1.04 @entity101 + 0.20; r = 0.987, p less than 0.001. Stratification of serum @entity2544 concentrations into different ranges showed that FPIA overestimated the @entity101 results in each range, but the percentage of overestimation was greater at lower concentrations (p less than 0.05). The use of FPIA seems appropriate in comparative studies of @entity2544 pharmacokinetics; however, the calculated kinetic parameters may differ slightly from those obtained with @entity101 .
