Synergic Effect of Sulfacetamide and Sulfadiazine in High Performance Liquid Chromatographic Determination of Their Mixture

[Background]Data accuracy in analytical determination is of prime importance. Antibiotic levels are usually obtained in mixtures using chromatographic techniques. Thus, evaluation of data accuracy in mixtures seems necessary.[Objectives]The aim of this study was to show how the figure of merits for high performance liquid chromatographic (HPLC) determination of sulfacetamide and sulfadiazine changes, while injecting their mixture compared to those injected individually.[Methods]Standard solutions of the mixture of 2 selected sulfonamides as well as each individual solution were injected on ODS2 C18 (250 × 4.6 mm, 5 µm) column. In each case, linear range, limit of detection, and recovery were evaluated.[Results]Three linear ranges with different sensitivity were observed for both antibiotics, while some that were injected simultaneously compared with those injected separately (just one linear range). The accuracy of the results was compared by both calibration curves (standards injected individually or simultaneously), and suitable calibration methods were introduced.[Conclusions]More precautions should be taken when determining antibiotics when they present as a mixture. Accordingly, a preliminary study is required to determine the accurate range when analyzing mixtures.