A voltammetric method for determining N-nitrosodimethylamine in losartan and olmesartan drugs

Recently, the National Health Surveillance Agency (ANVISA) of Brazil recalled several lots of sartan drugs due to the presence of N-nitrosodimethylamine (NDMA). NDMA is a highly potent carcinogenic contaminant that harms human health; therefore, the presence of NDMA in sartan drugs must be checked through appropriate analytical methods. This work successfully developed a new analytical method for determining NDMA without chemical pretreatment of losartan and olmesartan drug samples. The method uses the square-wave anodic stripping voltammetric (SWASV) technique, a boron-doped diamond electrode (BDDE), and a standard additions procedure (SAP). The proposed SWASV-BDDE-SAP method provided a linear response in the concentration range between 250 and 2500 nmol L^-1 (R² = 0.995, n = 10), a limit of detection (LOD) of 67.6 nmol L^-1, satisfactory accuracy (94.3% - 104.7%) without bias, and with good reproducibility (standard deviation = 5.6 %). The results obtained in determining NDMA in losartan and olmesartan drugs using the proposed and reference methods (HPLC-DAD) did not show a statistically significant difference, applying the paired t-test at a confidence level of 95%. In addition, the proposed method uses instrumentation with low acquisition, operation, and maintenance costs and enables rapid determination of NDMA in sartan drugs with great sensitivity, reproducibility, and stability. As the proposed SWASV-BDDE-SAP method does not use chemical pretreatment of samples, such as derivatization and/or extraction with reagents and/or organic solvents, it can be considered a promising eco-friendly alternative for determining NDMA in routine analysis, thus contributing to green analytical chemistry.