Analysis of Pyridostigmine Bromide in Human Plasma and its Application in Bioequivalence Studies.

A high performance liquid chromatographic (HPLC) method was developed using liquid-liquid extraction and ultra-violet detection for quantifying pyridostigmine bromide in human plasma. Liquid chromatography was performed on a BDS Hypersil C18 coulmn (5 µm, 250×4.6 mm i.d.) using an isocratic mobile phase comprised of acetonitrile-5 mM potassium dihydrogen phosphate (40:60, v/v) and the eluent was detected at 269 nm by UV. Clonazepam was used as the internal standard. The limit of quantification was 20 ng/mL using 1 mL plasma. The intra and inter-day precision expressed as the relative standard deviation was less than 15%. The assay was applied to the analysis of samples from a pharmacokinetic study. Following the oral administration of 60 mg pyridostigmine bromide (test) to volunteers, the maximum plasma concentration (Cmax), area under the curve (AUC) and elimination half-life (t1/2) were 176.03±9.176 ng/mL, 819.999±109.64 ng hr/mL and 3.787±0.08 hr, respectively. The method was demonstrated to be highly feasible and reproducible for pharmacokinetic studies of pyridostigmine bromide in humans. [ABSTRACT FROM AUTHOR]