Eco-Friendly Pharmaceutical Analysis of Rifaximin in Tablets by HPLC-MS and Microbiological Turbidimetry.

Rifaximin, an antimicrobial used for the treatment of various diseases, lacks analytical methods in official compendia for evaluation of the final product. This paper presents an eco-friendly protocol for rifaximin tablets by high performance liquid chromatography coupled with mass spectrometry (HPLC-MS). The method was completely validated according to the International Conference on Harmonization guidelines and developed following the concept of Quality by Design. The separation was achieved using a C18 column, purified water +0.1% glacial acetic acid and ethyl alcohol, 52:48 (v/v), as mobile phase, 0.9 mL min-1 at 290 nm and ambient room temperature. Mass spectral analyses were performed using electrospray ionization (ESI) ion source and ion trap mass analyzer. The method was linear over the concentration range of 5-50 µg mL-1. The sample was subjected to acidic, basic, neutral, oxidative and photolytic degradation. Degradation products did not interfere in the quantification of the rifaximin, so the method can be considered indicative of stability. Degradation products were also evaluated individually by microbiological method using Escherichia coli. The validated method could be used promisingly as green analytical strategies for detection and quantification of rifaximin in tablets.

Eco-friendly Evaluation of Rifaximin in Tablets by Capillary Electrophoresis.

Rifaximin, an oral antimicrobial, has no standardized analytical methods in many official compendia. In this context, the aim was to develop and validate an analytical method by capillary electrophoresis for quantification of rifaximin in tablets. The choice of capillary electrophoresis was based on the concepts of green analytical chemistry, taking into account the health of the operator and environment, analytical conscience, as well as the parameters of linearity, selectivity, precision, accuracy and robustness. The method was linear between 50 and 500 µg mL-1 (r = 0.9993) using purified water and ethanol in the sample preparation, silica capillary, borate buffer 25 mM pH 9.5, 20 kV and 290 nm. It presented good precision intraday (1.30%) and interday (1.56%). The accuracy complied with average recovery of 100.24%, as well as selectivity in the presence of impurities and degradation products and robustness against variations in the concentration, pH, rinse time of the buffer, voltage, wavelength, injection time and temperature. The capillary electrophoresis method developed for the evaluation of rifaximin tablets is low cost, fast, miniaturized, clean and environmentally friendly and can be used by laboratories and chemical and pharmaceutical industries for quality control of the drug.