Development and application of a radioimmunoassay for fluphenazine based on monoclonal antibodies and its comparison with alternate assay methods.

The development of a monoclonal antibody towards fluphenazine allows the measurement of plasma concentrations of this highly potent neuroleptic. The method demonstrates sufficient sensitivity to measure 0.02 ng of fluphenazine per milliliter of plasma and employs a 150-microL plasma extract derived from a 2-mL plasma sample. The procedure is linear over the concentration range of 0.02 to 2.5 ng/mL, with a mean overall coefficient of variation of less than 3%. The validity of the described monoclonal-based RIA procedure was confirmed by comparison to alternate assay methods in replicate samples. Comparison to a newly developed HPLC-coulometric procedure in 159 samples showed a strong correlation, with a slope value of close to unity (1.0484) and a coefficient of correlation of 0.8136, while comparison to a previously developed polyclonal-based RIA procedure showed a correlation of 0.95 and a slope of 0.91 (n = 26).