HPTLC/MS and HPTLC/UV for monitoring of degradation behavior of some β-Lactam antibiotics mixtures under ambient storage conditions

Stability testing of an active substance or final product is very crucial to ensure drug efficacy during shelf life. Simple and specific monitoring of β-lactam antibiotic combinations (with β-lactamase inhibitors) under ambient storage conditions was performed to better understand the kinetics of their degradation in powder for injection. The stored samples were analysed using HPTLC/MS and HPTLC/UV. The method employed HPTLC aluminum pre-coated plates with silica gel 60 F254 as the stationary phase. The used mobile phase systems consisted of ethyl acetate: acetonitrile: glacial acetic acid: water (5.5:3.0:2.0:1.0, v/v/v/v), for Magna-biotic® and ethyl acetate: acetonitrile: glacial acetic acid: water (5.0:3.0:2.0:1.0, v/v/v/v) for Unasyn® and Sulbacef®. The investigated mixtures were subjected to conditions resembling those found in a storage facility during different time intervals. The degradation behavior of powders for injection of the investigated mixtures, was found to be fitted to first-order kinetics, which is measured by observing the drug's starting concentration drop over time. The obtained results ensure the method's ability to assess the degradation kinetics of the tested combinations in the presence of their degradation products. The current study examines the drug's stability against high storage temperatures. MS detection was employed to elucidate the chemical structures of degradants and to confirm the suggested degradation pathway of the investigated mixtures in powder of injection. As a result, it is recommended that suitable protection measures against high temperatures must be followed during storage and handling of the investigated powder for injection of β-lactam antibiotics mixtures in order to maintain their biological efficiency.