Quantitation of sustained release of triptorelin in beagle dog plasma by liquid chromatography-tandem mass spectrometry

A sensitive method based on liquid chromatographytandem mass spectrometry has been developed for the determination of triptorelin in beagle dog plasma using octreotide as the internal standard. Plasma samples were applied to Oasis® HLB solid-phase extraction (SPE) cartridges. Detection with a Qtrap5500 system in the positive ion mode was performed through multiple reaction monitoring of the analyte at m/z 656.5→249.1 and of the I.S. at m/z 510.8→120.1. This method was validated by specificity, linearity, lower limit of quantification (LLOQ), intra and inter-day precision and accuracy, recovery, and stability. Linear calibration curves were obtained in the concentration range of 0.01- 10 ng/mL with the correlation coefficients better than 0.995. Its LLOQ was 0.01 ng/mL. This method has been successfully applied to a pharmacokinetic study for the sustained release of triptorelin in beagle dog plasma after a single intramuscular injection.