LC-ESI-MS/MS assay development and validation of a novel antidiabetic peptide PSTi8 in mice plasma using SPE: An application to pharmacokinetics.

•Analysis of PSTi8 peptide in mice plasma using SPE followed by LC–MS/MS has been developed for the first time.•Validation studies, including stability test of the developed method were performed.•The LLOQ was 5 ng/mL.•SPE has provided good recovery, cleaner samples and no matrix effect for PSTi8.•The absolute bioavailability of PSTi8 peptide was 52.74 ± 13.50 %.