A high-performance liquid chromatography method for detecting acylation impurities in acetate triptorelin microspheres for injection

An efficient high-performance liquid chromatography (HPLC) method was established to detect acylated impurities in triptorelin acetate microspheres for injection. Additionally, HPLC coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS) was employed to identify the types of acylated impurities. In HPLC, the separation of triptorelin and its acylated impurities was achieved on a Welch Ultimate XB-C18 column (250 mm × 4 mm, 5 μm). The mobile phase consisted of a 20 mmol·L^-1 aqueous solution of ammonium acetate (pH 6.9) and acetonitrile, delivered in a gradient elution mode with a flow rate of 0.5 mL min^-1. The detection wavelength was set at 210 nm. For the HPLC-QTOF-MS method, the aforementioned HPLC conditions were utilized, and the mass spectrometer employed an electrospray ionization (ESI) ion source in positive ion mode. The scanning range spanned from 100 to 2000 m/z. The carrier gas was N₂, with an atomization gas flow rate of 3 L·min^-1. The interface voltage was maintained at 4.5 kV, the desolvation temperature at 250 °C, and the drying gas flow rate at 15 L·min^-1. Additionally, the heating block temperature was set at 400 °C, and the interface temperature at 350 °C.

Results

Using this method, 14 types of acylated impurities in triptorelin were identified, further confirming that the acylation site of triptorelin is the serine alcohol hydroxyl group.

Conclusion

Both the HPLC and HPLC-QTOF-MS methods can be effectively utilized for routine quality control analysis of triptorelin acetate microspheres for injection.