Radioimmunoassay for desciclovir, 2-[(2-amino-9H-purin-9-yl)methoxy]ethanol, a prodrug for the antiviral acyclovir.

A direct radioimmunoassay for the detection of desciclovir (DCV)(2) in biological fluids has been developed. The radioimmunoassay was validated by comparing results obtained from human plasma samples analyzed by both this RIA and a gas chromatographic method. None of the crossreactivities noted interfere with the assay system. Although the succinylated antigen has a slightly higher affinity constant, the non-succinylated tritiated antigen was chosen for routine use. The assay is sensitive with an I50 value of 20 nM and with a lower limit of detection of about 3 nM. Intra-assay precision gave sample coefficients of variation which ranged from 2.2 to 9.6% for the standard curve with human plasma and from 2.0 to 8.2% for the standard curve with human urine. Inter-assay precision and accuracy were within acceptable limits.