The pharmaceutical industry in this country relies on foreign sources for a great many of the Bulk Pharmaceutical Chemicals (BPCs) used in the manufacturer of domestic dosage forms. As a result, many drug substances are available primarily or exclusively by importation. It is not unusual to find USP-NF monographs for certain BPCs which either have no specific impurity tests, or have impurity-limiting tests, which are inadequate because they are based on syntheses which have been partially or wholly supplanted.
An HPLC system using an ODS column and a mobile phase of 25% acetonitrile 75% 0.05M NH4AC resulted in the detection of five impurities in the BPC Diazoxide. Particle Beam EI LC/MS data and LC/MS/MS data were obtained and tentative identifications are reported. Four lots (representing two different manufacturers) all contained the same five impurities but in varying concentrations. Estimated concentrations ranged from less than 0.1% to 0.4%. Chemical Ionization LC/MS will be attempted to confirm the tentative identifications.