Development and Validation of an LC-MS/MS Method for Determination of Catalpol and Harpagide in Small Volume Rat Plasma: Application to a Pharmacokinetic Study

Abstract

A rapid and sensitive liquid chromatography-tandem mass chromatography (LC-MS/MS) method has been developed and validated for simultaneous determination of catalpol and harpagide in rat plasma. The samples were extracted by one-step protein precipitation and separated on a SunFireTM C 18 column (100 mm × 2.1 mm, 3.5 μm; Waters) using acetonitrile-10 mM ammonium formate as mobile phase at a flow rate 0.3 mL/min in gradient mode. The analytes were detected without interference in Multiple Reaction Monitoring (MRM) mode with negative electrospray ionization. Linear responses were obtained for catalpol ranging from 20 to 5000 ng/mL and harpagide ranging from 10 to 2500 ng/mL. Coefficients of correlation (r) for the calibration curves were more than 0.99 for both analytes. Intra-and inter-day accuracy and precision were within the acceptable limits of less than 15.0% at all concentrations. The quantitation method was successfully applied for simultaneous estimation of catalpol and harpagide after oral administration of Zeng Ye Decoction.

Simultaneous determination of three iridoid glycosides of Rehmannia glutinosa in rat biological samples using a validated hydrophilic interaction–UHPLC–MS/MS method in pharmacokinetic and in vitro studies

“…Given these findings, we selected (M+HCOO − ) − ions for aucubin ( m/z 391.1), catalpol ( m/z 407.1), and geniposide ( m/z 432.9), and (M‐H) − ions for IS ( m/z 379.9) as precursor ions; we selected the most abundant and stable fragment ions at m/z 183.1 for aucubin, m/z 199.0 for catalpol, m/z 225.0 for geniposide, and m/z 276.2 for IS as the product ions (as quantifier ions). These were in agreement with the findings of other researchers [24–26]. Figure 2 presents the relevant mass spectra.…”

“…1), catalpol (m/z 407.1), and geniposide (m/z 432.9), and (M-H) − ions for IS (m/z 379.9) as precursor ions; we selected the most abundant and stable fragment ions at m/z 183.1 for aucubin, m/z 199.0 for catalpol, m/z 225.0 for geniposide, and m/z 276.2 for IS as the product ions (as quantifier ions). These were in agreement with the findings of other researchers[24][25][26].Figure 2presents the relevant mass spectra. The qualifier ions of the analytes were as follows: m/z 45 and 345 for aucubin, m/z 169 and 361 for catalpol, m/z 101 and 183 for geniposide, and m/z 79 and 296 for IS.…”

“…[13, 14, 17], and 10 mmol/L ammonium formate buffer (pH 4.4) according to Ref. [24]. We found that when we used 10 mmol/L ammonium formate buffer as the mobile phase A, the sensitivity of the three iridoid glycosides improved in our system and the peaks separated completely.…”

“…Supporting Information Table S2 shows the recoveries and matrix effects for three iridoid glycosides; the extraction recoveries ranges of aucubin, catalpol, and geniposide from rat plasma, urine, and feces were 88.95-91. 24 The results indicated that the extent of the analyte recoveries was consistent, precise, and reproducible. These simple PP and LLE procedures were successfully applied to measuring of aucubin, catalpol, and geniposide in rat plasma, urine, and feces.…”

“…However, these results were unsatisfactory for chromatograms of the three iridoid glycosides owing to high noise and low sensitivity; in addition, we observed high column pressure. The use of 100% methanol as the mobile phase for the elution of polar iridoid glycosides in the HILIC column did not seem suitable, but when we used 100% acetonitrile (the difference is not great, but slightly more polar than methanol) as the mobile phase B following other references [17, 24], the peak sensitivity of the analytes increased, the noise decreased, and the column pressure decreased as well. We also tested different buffers of varying pH as a mobile phase A, which included 0.1% formic acid in water (pH 2.2) according to Refs.…”