A radioreceptor assay for determination of nicardipine in human serum using 3H(+)PN 200-110 as radioligand

A radioreceptor assay for the determination of nicardipine in human serum using the active enantiomer 3H(+)PN 200-110 as radioligand is described. The assay is simple to perform, of low cost and requires only a small volume of serum. The standard curve permits measurements in the range 2.5 to 320 nM nicardipine (i.e. 1.2 to 153 ng/ml). The precision and the reproducibility of the method, evaluated from two different concentrations: 120 and 12 nM, show coefficients of variation for within and between assays, of 6% and 15% and 6% and 9%, respectively. Concentrations of nicardipine from 3 ng/ml could be measured with a satisfactory precision. The performances of the method permit the determination of nicardipine concentrations reached after therapeutic administration. Other dihydropyridine calcium channel antagonists may be measured using this assay if these compounds are used to generate the standard curves