Identification, characterisation and in silico ADMET prediction of ozenoxacin and its degradation products using high‐performance liquid chromatography‐photodiode array and liquid chromatography‐quadrupole time‐of‐flight‐tandem mass spectrometry

Rationale Ozenoxacin (OXC) is an antibiotic used topically to treat impetigo. This study aimed to evaluate the degradation products (DP) of OXC drug substance under different stress conditions, including hydrolysis, oxidation, thermal and photolysis, in accordance with the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines Q1A(R2) and Q1B. The analytical technique was validated in compliance with ICH Q2(R1) requirements. Methods The drug substance underwent degradation under various forced degradation conditions, including thermal, oxidative, photolytic and hydrolytic (neutral, acidic and basic) degradation. Overall, four DPs were formed under oxidative stress conditions with AIBN. The formed DPs were identified and separated using a Shimadzu LC system with a reversed‐phase Phenomenex Kinetex C18 column (4.6 × 250 mm, 5 μm), using 10 mM NH 4 CH 3 COOH buffer (pH −5.0) as mobile phase A and acetonitrile as mobile phase B at a detection wavelength of 254 nm. Results and Conclusion The drug was found to be stable in neutral, acidic, basic and oxidative degradation conditions with hydrogen peroxide. Liquid chromatography‐electrospray ionisation‐quadrupole time‐of‐flight‐tandem mass spectrometry‐ was employed in positive ionisation mode to analyse both the drug and the mass of the identified DP. The mechanism and the pathway of mass fragmentation have been proposed. The developed method was accurate, repeatable, linear and selective for further research. The ADMET Predictor software was applied to predict the in silico toxicity of the drugs and its DPs as well as their physicochemical characteristics.