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The frequent contamination of water resources with drugs comprises one the most important environmental problems. In order to avoid serious disturbances for aquatic life, efficient and economically viable procedures should be developed for removing common pollutants, as paracetamol. From these considerations, the present work evaluated the efficiency of sugar cane bagasse (SCB) and vegetable sponge (VS), two natural adsorbents commonly found in Brazil, for retaining paracetamol molecules dispersed in aqueous solutions. Thus, systems composed of glass columns and peristaltic pumps were optimized and, for pH, the best value was 7.0. After optimisation, adsorption isotherms were built and it was possible to calculate the MACF values for SCB (120.5 µg/g) and VS (37.5 µg/g). Additionally, real matrices of pretreated water, from a municipal plant for water catchment, were enriched with paracetamol at 5 µM and passed through glass columns packed with SCB, VS and activated carbon (AC). The results showed that SCB was more attractive than AC in terms of price and efficiency (60% against 45% adsorption, respectively), while VS was responsible for removing 40% of paracetamol dissolved in the enriched water samples. Thus, the proposed natural adsorbents can be classified as viable materials to remove paracetamol from water used for human consumption.

This work proposes a critical alteration in the official methods using high performance liquid chromatography (HPLC) to quantify the active pharmaceutical ingredient captopril and its major degradation product, captopril disulfide, present in captopril tablets. Analytical alternatives were studied to minimize captopril oxidative degradation for a 24-hour period in order to ensure sample solution stability and thereafter the analytical data reliability. Captopril degradation in solution is discussed in detail in this article. Six captopril 25 mg tablets commercial batches were used in this study. The analytical method was based on the official methods described in the Brazilian Pharmacopoeia 5 th edition and The United States Pharmacopeia 36 th edition (USP 36). For the analytical method development, a comparative stability study of captopril tablet commercial batches sample solutions was carried out within a 24-hour period using three different solvents to evaluate sample diluent solution better stability. The results demonstrate that samples prepared in methanol presented the best stability performance within the period studied unlike the samples prepared in diluent system described in the official product monographs.