Identification and characterization of degradation products of dicloxacillin in bulk drug and pharmaceutical dosage forms

Impurity profiling of dicloxacillin sodium bulk drug and pharmaceutical dosage forms subjected to stability studies is evaluated. Of many impurities detected in HPLC analysis, three were not reported in the literature. The impurities have been identified by LC-MS; isolated by preparative HPLC; and characterised by NMR, Mass spectroscopy and IR. Pure impurities obtained by isolation were co-injected with dicloxacillin sodium sample to confirm the retention times in HPLC. Structure elucidation of these degradation products by spectral data has been discussed in detail.