DETERMINATION OF MK-383, A NONPEPTIDE FIBRINOGEN RECEPTOR ANTAGONIST, IN HUMAN PLASMA AND URINE BY RADIOIMMUNOASSAY

MK-383 is a novel, non-peptide fibrinogen receptor antagonist. A sensitive and specific radioimmunoassay has been developed for the determination of this drug candidate in plasma and urine. The immunogen was prepared by coupling to albumin via the N-hydroxysuccinimide ester from which the radioligand was also prepared by reaction with [I-125]iodotyrosine. The method was specific and no immunoreactive material other than the parent drug was detectable in plasma and urine from dosed volunteers. This direct assay, using 5 mu l of plasma or 0.5 mu l of urine, is sensitive to 1 and 10 ng ml(-1), respectively, without matrix interference and has sufficient sensitivity, specificity, accuracy, and precision for the analysis of clinical samples.