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Selective approaches in analytical chemistry are essential in drug analysis. Spectroscopic methods are often performed to identify drugs, and electroanalysis is mostly used in quantitative assays. However, chemometrics are tools that can be applied to analytical methods in order to enhance selectivity. Thus, the aim of this work was to propose a novel drug identification approach with electroanalysis with several classification algorithms and to compare those results with Raman spectroscopy. The commercial tablets and analytical standards of diclofenac, amoxicillin, hydrochlorothiazide, bromazepam, piroxicam, sulfadiazine, albendazole, cyclobenzaprine and ibuprofen were studied. The classification approaches of linear discrimination analysis (LDA), partial least squares discriminant analysis (PLSDA), support vector machine and k-nearest neighbours (KNN) were employed. Differential pulse voltammetry and Raman spectroscopy were used. The models AS, CT and AS-CT were proposed by the division of the dataset in three parts, being only the analytical standards (AS), only the commercial tablets (CT) and both analytical standards and commercial tablets (AS-CT). For voltammetry and Raman LDA and PLSDA yielded the best accuracy in model AS. For the commercial tablets (model CT), voltammetry showed better performance than Raman. In model AS-CT the KNN classifications displayed better accuracy for both voltammetry and Raman. Voltammetry showed a great performance in the identification of analytical standards and commercial tablet drugs, higher versatility and easier employment due to the nonrequirement of variable selection in comparison to Raman and showed a better performance than Raman for the identification of commercial tablets.

Rituximab (RTX) is a specific monoclonal antibody for CD20 protein, which are mostly found in lymphocytes B. RTX is notably indicated for lymphomas, autoimmune disorders, leukemia and transplant rejections. A higher efficiency is achieved by adjusted doses, which is tailored by individual body weight and RTX pharmacokinetic parameters. Therefore, the individualized dosing is a usual practice to achieve the therapeutic success of this expensive drug. Therapeutic monitoring of RTX is commonly performed by chromatographic methods or immunoassays. These methods, however, suffer from lack of standardization in workflows, long turnaround times and high instrumentation costs with complex sample preparation. In this regard, immunosensors emerge as a feasible alternative to overcome these limitations. Herein, we developed an impedimetric immunosensor, which can detect RTX from both invasive and non-invasive samples, in this way our immunosensor is applicable in blood plasma and urine samples allowing a new analysis approach. A linear correlation between the charge transfer resistance and RTX from 2 to 14 μg ml−1(r2of 0.99) along with limit-of-detection and limit-of-quantification of 130 and 400 ng ml−1, respectively, was obtained. The immunosensor implemented proved to have sufficient precision and accuracy for on-site RTX detection in both blood serum and urine samples. Such affordable, label-free and highly sensitive electrochemical immunosensors could pave the way for on-site therapeutic drug monitoring, quality control and extended stability monitoring of different drugs, in a simple manner along with short turnaround times and low costs.

Benzimidazoles, such as albendazole (AB) and mebendazole (MB), are common anthelmintic agents, widely used throughout the world to combat parasitic diseases. The electroanalytical sensing of AB and MB based on Perovskite-Type LaFeO3nanoparticles modified sonogel carbon paste electrodes has been reported for the first time. Perovskite-type LaFeO3nanoparticles were characterized by X-ray diffraction (XRD), fourier transform infrared (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD indicates the formation of monophase perovskite LaFeO3and FT-IR spectrum shows a band at 570 cm−1which is associated to the formation of lanthanum ferrite. Microscopy images show that the distribution in pore size and shape is not well defined. The particles sizes are found to be above 200 nm. It was found that sonogel carbon paste modified electrodes with Perovskite-type LaFeO3nanoparticles exhibit higher catalytic activity and sensitivity toward the detection of AB and MB compared to the unmodified electrode. The limits of detection for albendazole and mebendazole were reported to be 0.3 μM and 0.6 μM respectively and the limits of quantification 0.8 μM and 1.7 μM respectively. The electroanalytical protocol was successfully applied for the sensing of AB and MB in pharmaceutical formulations.