Pharmacokinetic analysis of orally administered puerarin in human saliva using an indirect competition ELISA

Abstract

Puerarin (4′,7-dihydroxy-8-β-D-glucoside isoflavone) is the main active component in pueraria extracts, and it has several medicinal properties. Clinical pharmacokinetic studies and puerarin measurements are currently being performed on blood samples collected from patients or volunteers (treated with puerarin) using High Performance Liquid Chromatography (HPLC). However, the collection of saliva samples is simple, easy and non-invasive. The enzyme-linked immunosorbent assay (ELISA) is a sensitive, rapid and efficient method that can be used to analyze puerarin in human saliva. In this study, we developed an indirect competition (ic) ELISA assay for concentration measurements and pharmacokinetic analysis of puerarin in human saliva following oral administration of pueraria capsules in thirty healthy volunteers. We observed a linear correlation in the range of 5 ng mL⁻¹ to 1280 ng mL⁻¹ with a regression coefficient of 0.9939, which was between the actual and icELISA-measured concentrations of puerarin. Both intra-day and inter-day repeatability and precision were achieved, with the relative standard deviation (RSD) being lower than 15%. A mean recovery of 95–115% was obtained with an RSD lower than 15%. Stability studies indicated that puerarin is stable during the sample preparation and analysis. There was a good correlation between the icELISA and HPLC methods (R² = 0.9916) for the determination of puerarin in saliva. Our study shows that the validated icELISA method can be successfully applied to study the pharmacokinetics of puerarin in human saliva.