Simultaneous Determination of Doxecitine and Doxribtimine in Bulk Drug and Pharmaceutical Formulation by Reverse-phase Ultra-performance Liquid Chromatographic with Photodiode Array Detection: Method Development and Validation

Abstract

Objective: The present investigation was undertaken to establish a reliable, sensitive, and efficient reverse- phase ultra-performance liquid chromatographic (RP-UPLC) technique for the concurrent quantification of two pharmacologically significant nucleoside compounds, doxecitine and doxribtimine, in their pure forms and in tablet formulations. Materials and Methods: Chromatographic separation was achieved on a phenyl column (100 × 2.1 mm, 1.7 μm particle size) using an isocratic mobile phase of acetonitrile and water (30:70, v/v) buffered to pH 2.5 with formic acid. The system was operated at a flow rate of 0.5 mL/min, and detection was performed at 229 nm with a photodiode array detector. Full validation was carried out in accordance with International Conference on Harmonisation (ICH) Q2(R1) guidelines. Results: Both analytes exhibited linearity across the
concentration range of 50–300 μg/mL, with correlation coefficients (R2) of 0.9998 and 0.9996 for doxecitine and doxribtimine, respectively. The limit of detection was 0.40 μg/mL, and the limit of quantification was 1.0 μg/mL
for each compound. Recovery, precision, and robustness data were all within ICH-specified acceptance criteria. Conclusion: The validated RP-UPLC method presented here offers a fast, cost-effective, and dependable tool for routine quality control of doxecitine and doxribtimine, including stability testing at multiple time points, in both bulk drug substance and finished pharmaceutical products.