Immunochromatographic determination of bacopaside I in biological samples

•A novel immunochromatographic assay for qualitative and quantitative analyses of bacopaside I in biological samples.•The assay was performed on polyethersulfone membrane using a polyclonal antibody raised against bacopaside I.•Applicable for in vivo pharmacokinetic study.

We describe a novel immunochromatographic method for qualitative and quantitative analyses of bacopaside I, a bioactive constituent in Bacopa monnieri (L.) Wettst in biological samples. The assay was performed on polyethersulfone membrane using a polyclonal antibody raised against bacopaside I. The finalised method could quantitatively determine bacopaside I in the range of 31.3-1000.0 ng and the detection and quantification limits were 1.0 and 31.3 ng, respectively. The percentage recoveries of bacopaside I in blood and urine were nearly 100% indicating the accuracy of the extraction. The method was then applied for the determination of this compound in rat serum, urine and feces after an oral dose of 15 mg/kg body weight. About 4% of the ingested dose of bacopaside I was detected in rat feces but none was detected in serum and urine which accorded with results from liquid chromatography tandem mass spectrometry. The accuracy, selectivity, sensitivity of the method are appropriate for in vivo pharmacokinetic studies.