Radioimmunoassay for MPV-295, a new antihypertensive drug

A specific and simple radioimmunoassay for the determination of MPV-295, 4(5)-[2-(2,6-dimethylphenyl)-ethyl]imidazole, in human serum is described. The antibodies were produced in rabbits immunized with a conjugate of MPV-295 and bovine thyroglobulin prepared by diazo reaction. They were shown to be specific for MPV-295 tested against several synthetic analogues. MPV-295 was iodinated with the chloramine-T method and 125I-MPV-295 was purified in cation exchange chromatography for use as tracer. The sensitivity of the assay is 2-5 pmol/ml depending on the sample volume. Serum determinations were carried out directly with 20-50 microliter serum volumes. This assay has been used to monitor serum levels of MPV-295 in pharmacokinetic studies in healthy and hypertensive subjects.