In this investigation, a highly reliable, precise, stability indicating, specific and selective RP-HPLC
approach with photodiode array detection (RP-HPLC-PDA) was established to determine
simultaneously imipenem, cilastatin and relebactum in bulk drug and injection dose forms.
Chromatographic separation of imipenem, cilastatin and relebactum was achieved via using C18 XTerra
column and a mobile phase poised of acetonitrile and 0.1 M dipotassium hydrogen phosphate buffer
(4.5 pH, set with 0.1% orthophosphoric acid) at 45:55 (v/v) ratio with a flow stream of 1 mL/min. The
photodiode array detector was fixed at wavelength 245 nm and quantifications of imipenem, cilastatin
and relebactum were based on assessing their peak response areas. Good linearity was detected in
target range concentrations of 250-750 μg/mL (imipenem and cilastatin) and 125-375 μg/mL
(relebactum). The precision (standard variation percentage) was between 0.141% and 0.257%. Accuracy
(%assay nominal) determined was between 99.144% and 99.638%. The validated RP-HPLC approach
was applied to Recarbio injection dose evaluating imipenem, cilastatin and relebactum content with
no interference encountered from the injection dose inactive ingredients. Imipenem, cilastatin and
relebactum were subjected to forced conditions like 30% peroxide, 0.1 N NaOH, sunlight, 0.1 N HCl
and 60 ºC. Imipenem, cilastatin and relebactum were effectively separated, quantified and resolved
from the degradants generated in forced conditions.