Title : Microbiological pharmaceutical analysis: Better safe than sorry
Abstract:
Rifaximin, an oral antimicrobial, is mainly used for the treatment of hepatic encephalopathy, but also in cases of ulcerative colitis, irritable bowel syndrome, Clostridium difficile, travelers' diarrhea and acute diarrhea. Rifaximin does not present microbiological methods described in official compendiums and they are extremely important and necessary in the evaluation of power of antimicrobials. So, a microbiological method by turbidimetry was developed and validated to evaluate the power of rifaximin in tablets and its degradation products (acidic, basic, neutral and photolytic), as well as rifaximin raw material recrystallized from different solvents. The results were compared with analyzes by HPLC. The method used Escherichia coli and was linear over the concentration range of 50-98 μg mL-1, precise with values of relative standard deviation less than 5 %, exact by the recovery test and robust against small and deliberate variations in the method. The potency, by turbidimetric method, of rifaximin in tablets after degradation in basic and photolytic media was different from that revealed by the HPLC method. The potency, by turbidimetric method, of rifaximin in raw material after treatment with different solvents also showed different results from the HPLC method. In these cases, the physico-chemical method showed much higher contents than the potencies revealed by the microbiological method. Production of rifaximin involves the use of different solvents and the performance of these solvents can affect the activity of the antimicrobial, which is not always correctly revealed by physico-chemical methods. This is an alert to the production of pharmaceutical inputs and the presence of microbiological analyzes throughout the industrial process. The process of obtaining raw material must be standardized, aiming not only the quality of the medicine, but also, aiming the consequences of the use of non-quality medicines that generate a vicious cycle in the public health system. Antimicrobials should be analyzed by microbiological methods in conjunction with physico-chemical methods. The quality of a pharmaceutical product is directly related to the health of patients and a reliable analysis method can be the first step in the rational use of pharmaceuticals.
Audience take away:
• A reliable, effective, practical, simple, fast and low cost option for microbiological analyzes.
• The turbidimetric method is ideal for dynamic logistics of Quality Control of antimicrobials and can be easily applied in laboratories and pharmaceutical industries.
• It reveals the true activity of the antimicrobial often not detected by physicochemical methods.
• It can be and should be expanded and applied by laboratories, industries and research centers around the world. The use of microbiological methods should be encouraged concomitantly with physicochemical methods with the objective of take care of the quality of drugs and medicines that arrive to patients.
• The quality of a pharmaceutical product is directly related to the health of patients and a practical analysis method and accurate can be the first step in the rational use of pharmaceuticals.
