An UPLC-MS/MS method for determination of karacoline in mice and its pharmacokinetics study

In this experiment, ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was employed to quantify karacoline in mouse plasma following both intravenous and oral administration, thereby elucidating the pharmacokinetic characteristics of karacoline in mice. The analytes were extracted from mouse plasma using acetonitrile for protein precipitation. Chromatographic separation was performed on an HSS T3 column via gradient elution, with the mobile phase consisting of methanol and 0.1% formic acid in water. Quantification of karacoline and the internal standard (IS) was achieved using multiple reaction monitoring (MRM) mode. Six mice received an intravenous (i.v.) injection of karacoline at a dose of 1 mg kg⁻¹, while another six mice were administered karacoline orally (p.o.) at a dose of 5 mg kg⁻¹. The calibration curve for karacoline in mouse plasma ranged from 1 ng mL⁻¹ to 2,500 ng mL⁻¹. The intra-day precision was within 10.4%, and the inter-day precision was within 13.0%. Accuracy ranged from 89.1% to 107.5%, with recovery rates between 77.6% and 88.2%. Matrix effects were observed within the range of 77.6%–107.4%. This method successfully estimated the pharmacokinetics of karacoline, and its bioavailability was determined to be 27.2%, these are preliminary studies that require verification on a larger group of animals.