Determination of Protodioscin in Rabbit Plasma by LC-MS/MS Method: Application to Preclinical Pharmacokinetics

Background: Protodioscin, a furostanolic saponin type phytocompound, is claimed to have aphrodisiac and anticancer activities. Determination of protodioscin is challenging problem since it lacks chromophoric or florophoric groups. Pharmacokinetic data after administration of protodioscinrich extract prepared from Trigonella foenum-graecum in rabbit was not yet reported. A selective and sensitive LC–MS/MS method with solid phase extraction was developed and validated to quantify the concentration of protodioscin in rabbit plasma. Methods: Chromatographic separation was accomplished by using a Shiseido Spolar C18 column (150.6 mm, 5μ) with a mobile phase consisting of 0.2% formic acid in Milli-Q water-acetonitrile (40:60, v/v) at a flow rate of 0.5 mL min-1. Digoxin was used as an internal standard. Samples were prepared by solid phase extraction using Orochem C18 cartridges. A triple quadrupole tandem mass spectrometer with ESI was used as a detector operated by multiple reaction monitoring in positive ion mode with m/z 1031.3→869.2 and m/z 798.4→651.7 for protodioscin and internal standard, respectively. Results: The calibration curve was linear (r2 ≥ 0.99) over the concentration range of 0.1 to 100 μg/mL. The precision, accuracy and stability experiments results were meeting the acceptance criteria. Conclusion: The method can be applied to study the pharmacokinetic parameters of protodioscin in rabbit.