Determinação do teor de etanol em medicamentos homeopáticos por entalpimetria no infravermelho

Abstract

In this work, a simple and fast method is proposed for ethanol determination content in homeopathic medicines by thermal infrared entalpimetry (TIE). Samples containing appropriate alcohol concentration range were compounding in order to obtained representative manufacturing process. Reagent (purified water or absolute ethanol) was added directly into homeopathic medicine and temperature increase caused by heat of dilution was monitored using an infrared camera. Total volume, agitation speed and micropipette dispensing rate were the most significant parameters studied to method optimization. A design-of-experiments (DoE) was taken in the collection of the data, and the results were then modeled using statistical modeling software. The method was validated in the following parameters: selectivity, linearity, linear range, precision (repeatability and intermediate precision), limit of detection and quantification, accuracy and robustness. Linear range was obtained from 4% (ethanol, v/v) to 55% (ethanol, v/v). The method showed accuracy based on agreement with official method and declared value. Thus, the TIE it was demonstrated a good alternative for the determination of ethanol in homeopathic medicines, presenting advantages over the conventional methods, such as low cost, faster analysis and compliance with the principles of green chemistry.