Pharmacokinetics of pefloxacin mesylate in human urine using capillary electrophoresis electrochemiluminescence detection

A novel and simple method to determine pharmacokinetics of pefloxacin mesylate (PM) in urine of seven healthy adults was developed. The proposed methodology was based on the electrochemiluminescence (ECL) of tris(2,2′-bipyridine)ruthenium (II) at a platinum electrode. The ECL intensity was found greatly enhanced in the presence of PM, which could directly participate in the light-emitting reaction as the reductant (in former/unchanged form). Under optimised conditions, the calibration curve was linear from 0.02 to 12 mg/L with a detection limit of 0.004 mg/L (σ = 3). The RSD of the peak height was less than 2.4% (n = 6). The recoveries in human urine were 96.2% to 98.3%. The highest excretion rate in urine was observed during the period 1.5–2 h after oral administration. The urinary excretion ratio of PM was 13.6% within 48 h.