High-performance liquid chromatographic assay of the aldose reductase inhibitor spiro-(2-fluoro-9H-fluorene-9,4'-imidazolidine)-2',5'-dione (AL01567) in plasma and urine and its pharmacokinetics in humans.

Two selective high-performance liquid chromatographic (HPLC) methods have been developed for the quantitative determination of spiro-(2-fluoro-9H-fluorene-9,4'-imidazolidine)-2',5'-dione (AL01567; 1) in plasma and urine, with an assay sensitivity of 0.25 micrograms/mL for plasma and 0.13 micrograms/mL for urine. The plasma assay procedure involved precipitation of proteins with acetonitrile followed by dilution with water. The diluted supernatant was analyzed on an ODS column eluting with acetonitrile:0.5% phosphoric acid (30:70) adjusted to pH 7.2 with concentrated ammonium hydroxide. The urine assay procedure involved extraction of 1 with 10% n-butanol in hexane, followed by back extraction with 0.05 M sodium hydroxide. The basic extract was neutralized and analyzed on a phenyl column eluting with acetonitrile:10 mM potassium phosphate (30:70; monobasic, pH 5.6). The pharmacokinetics of 1 was investigated in humans following single and multiple oral doses. The elimination half-life from 12 normal subjects following single 100-400-mg oral doses was independent of dose, and the overall mean half-life was 66 +/- 9 h. The overall mean oral clearance (assuming a bioavailability of 100%) was 11 +/- 3 mL/min, and the mean apparent volume of distribution was 59 +/- 13 L. The mean urinary recovery of intact drug during the first 24 h after dosing was 1.2 +/- 0.4% of the administered dose. During once daily 100-mg oral dosing of 1 to five subjects for 21 d, plasma concentrations of 1 reached apparent steady-state by 7 d.(ABSTRACT TRUNCATED AT 250 WORDS)