Evaluation of Rifaximin Potency by New, Fast and Low-Cost Microbiological Method

Ana Carolina Kogawa, Universidade Estadual Paulista, Araraquara, Brasil (ac_kogawa@yahoo.com.br)
Hérida Regina Nunes Salgado, Universidade Estadual Paulista, Araraquara, Brasil

Rifaximin is an oral antimicrobial very used for its treatment diversity, among them hepatic encephalopathy, ulcerative colitis, irritable bowel syndrome, Clostridium difficile, travelers' diarrhea and acute diarrhea. For this reason, the quality control of this pharmaceutical product is essential. In this context, microbiological analytical methods are welcome for this evaluation, since they complement the physicochemical results. Thus, a new microbiological method by turbidimetry was developed and validated for the evaluation of the potency of rifaximin in tablets. The method was linear and selective over the concentration range of 50-98 μg mL^-1 with correlation coefficients 0.9976 (standard) and 0.9999 (sample), precise (intraday RSD = 4.96 and interday RSD = 3.92), exact (recovery 100.70 %) and robust against small and deliberate variations in the method using Escherichia coli ATCC 10536. The method can also be considered indicative of stability since it was able to evaluate the potency of the product based on rifaximin after stress conditions in acid, alkaline, neutral and photolytic media. The turbidimetric method developed, besides being adequate and reliable for the routine analysis of rifaximin in tablets, has other advantages such as speed (4 hours versus 24 hours of the traditional agar diffusion method), which allows better optimization of time, analyst activities and equipment, lower volume of material used, automated results, which allow greater confidence in the data obtained and easier handling. Therefore, this new proposal using microbiological turbidimetry can be used safely, effectively and with numerous advantages in the evaluation of rifaximin in tablets by laboratories and pharmaceutical industries around the world.

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Abstract Reference & Short Personal Biography of Presenting Author

My name is Ana Carolina Kogawa, I am Pharmaceutical-Biochemistry by UNESP and Master and PhD in Pharmaceutical Sciences also by UNESP. I have Black Belt-Six Sigma Training, which helped me enormously in performing activities, planning experiments, problem solving, and teamwork. Currently, I carry out post-doctoral research at UNESP in the areas of Pharmaceutical Technology and Physico-chemical and Microbiological Quality Control of Drugs and Medicines.

So far, I have more than 60 scientific articles published. During my Master, PhD and post-doctoral studies I participated in national and international events through presentation of poster and oral papers in London (UK), Osaka (Japan), Valencia (Spain), Rome (Italy), Lisbon (Portugal), Berlin (Germany), Paris (France), Ghent and Liege (Belgium), Cordoba and Rosario (Argentina), Cartagena de las Indias (Colombia) and several cities in Brazil. I am a reviewer of 22 international journals, which are described in the curriculum. I co-supervised and co-supervise undergraduate, master and doctoral students. My index h = 10 and Index i10 = 10.

My area of activity is the physico-chemical and microbiological quality control of drugs and medicines aimed at green analytical chemistry and everything that involves it. Our concern for quality is multidimensional. It covers the health of the analyst, the chosen reagents, the treatment of residues, the amount of residues formed, the toxicity of the reagents, the accessories used, the analysis time, the chosen technique, the equipment of protection, physical and emotional well-being, the environment and, of course, safe and effective pharmaceutical analyzes.

My projects also aim to work in a multidisciplinary way interacting in different laboratories: Quality Control and Pharmaceutical Technology; different equipment: spectrophotometer, chromatograph, dissolutor, X-ray diffractor; different methods: wet milling, complexation, spectrophotometry in the ultraviolet, visible and infrared regions, high performance liquid chromatography, microbiological turbidimetry, dissolution; and different people. I believe that this interaction is rich and my goal is always to strengthen the group with the teachings brought and lived in other laboratories with other ways of working, I believe that networking nowadays is differential and can bring great opportunities. In this way, we improve ourselves, become integrated people and contribute to world literature and benefit the community, the population, since we think in a multidimensional way focusing on the whole, the parts and, above all, the interaction between the parts of a system.