A Modern Method for Analyzing Related Substances of Cabotegravir and Rilpivirine Using RP-HPLC, along with the Characterization of their Degradation Products Via LCMS

Abstract

Introduction: The estimation, separation, and validation of Cabotegravir and Rilpivirine along with their
impurities were performed using the RP-HPLC technique. Materials and Methods: Cabotegravir, Rilpivirine,
and their respective impurities were separated on an Inertsil ODS column (150 × 4.6 mm, 3.5 μ) using a
mobile phase consisting of 5 mM Ammonium Formate and acetonitrile at a flow rate of 1 mL/min at room
temperature. The PDA detector from a Waters HPLC e-2695 quaternary pump was used with a wavelength of
231 nm. The linearity was investigated for 17 min with injection concentrations of 75–450 μg/mL of Rilpivirine,
50–300 μg/mL of Cabotegravir, and 1.25–7.5 μg/mL of each impurity of Cabotegravir and Rilpivirine. The validity
of the proposed method was verified using the International Conference on Harmonization (ICH) guidelines.
Results and Discussion: The results of method validation including specificity, linearity, accuracy, ruggedness,
and robustness were within the permissible range. Conclusion: The HPLC-MS technique successfully validated
the chemical structures of the degradation products of Cabotegravir and Rilpivirine, and stress studies were carried
out in compliance with ICH Q2 (R1) guidelines