A validated UPLC-MS/MS method for quantitative determination of a potent neuroprotective agent Sarsasapogenin-AA13 in rat plasma: Application to pharmacokinetic studies.

Sarsasapogenin-AA13(AA13), a sarsasapogenin derivative, exhibited good neuroprotective and anti-inflammatory activities in vitro and therapeutic effects on learning and memory dysfunction in amyloid-ß-injected mice. A sensitive UPLC-MS/MS method was developed and validated to quantitatively determine AA13 in rat plasma and was further applied to evaluate the pharmacokinetic behaviour of AA13 in rats that were administered AA13 intravenously and orally. This method was validated to exhibit excellent linearity in the concentration range of 1-1000 ng/mL. The lower limit of quantification was 1 ng/mL for AA13 in rat plasma. Intra-day accuracy for AA13 was in the range of 90-114%, and inter-day accuracy was in the range of 97-103 %. The relative standard deviation of intra-day and inter-day assay was less than 15%. After a single oral administration of AA13 at the dose of 25 mg/kg, Cmax of AA13 was 1266.4 ± 316.1 ng/mL. AUC0-48 h was 6928.5 ± 1990.1 h·ng/mL, and t1/2 was 10.2 ± 0.8 h. Under intravenous administration of AA13 at a dosage of 250 µg/kg, AUC0-48 h was 785.7 ± 103.3 h⋅ng/mL, and t1/2 was 20.8 ± 7.2 h. Based on the results, oral bioavailability (F %) of AA13 in rats at 25 mg/kg was 8.82 %.