An adequate analytical method can be the first step in the rational use of pharmaceuticals. Currently, however, the effectiveness of the method of analysis is not enough. It should also be environmentally friendly, dynamic and low cost. A product can present more than one analytical method for its evaluation, and then, before adopting any of them, it is necessary to know if they are equivalent. Comparison of methodologies is necessary to determine if the variability of the methods differs significantly. Rifaximin, an antimicrobial, presents analytical methods by spectrophotometry in the ultraviolet region (UV), spectrophotometry in the infrared region (IR), capillary electrophoresis (CE), high performance liquid chromatography (HPLC) and Turbidimetry for evaluation of its tablets. This work shows the comparison of these methods in the evaluation of the final product quality of rifaximin, in addition to comparing the equivalence of physical (UV, IR, CE, HPLC) and microbiological (Turbidimetric) methods. The analysis of rifaximin tablets by physico-chemical and microbiological methods were statistically equivalent and can be interchangeable. However, it should be remembered that in the case of antimicrobials, such as rifaximin, the simultaneous analysis by a physico-chemical method and a microbiological method is fundamental for the release of reliable results.
•Analytical methods can be the first step in the rational use of pharmaceuticals.
•Comparison of methodologies determines if the variability of the methods differs significantly.
•The analysis of rifaximin tablets by physico-chemical and microbiological methods were statistically equivalent and can be interchangeable.