Development and validation of an enzyme-linked immunosorbent assay for the quantification of gelonin in mouse plasma

This article details the development and validation of an enzyme-linked immunosorbent assay (ELISA) for the quantification of gelonin in mouse plasma. The ELISA was validated for intra- and inter-day variability and for accuracy over a standard curve range of 7.5–100 ng/mL. The assay was then applied to assess gelonin pharmacokinetics in mice. Results from the ELISA were compared to data obtained from a parallel study conducted with ¹²⁵Iodine-labeled gelonin, with quantification via gamma counting. The ELISA demonstrated good precision, as the percent coefficient of variation of quality control samples in intra-day and inter-day validation ranged from 5.4–9.3% and 2.9–7.3%, respectively. Sample recoveries ranged from 98.3–105% of nominal values. The ELISA method yielded lower plasma concentrations of gelonin than found from the less-specific gamma counting method. Consequently, pharmacokinetic analyses yielded significantly higher estimates for volume of distribution (106 ± 31 vs. 55.8 ± 13 mL/kg) and plasma clearance (34.7 ± 6.6 vs. 10.9 ± 2.1 mL/min/kg) for data determined by ELISA vs. by gamma counting.