Photolytic and photocatalytic transformation of an antipsychotic drug asenapine: Comparison of kinetics, identification of transformation products, and in silico estimation of their properties

Mussel-Inspired Immobilization of Photocatalysts with Synergistic Photocatalytic-Photothermal Performance for Water Remediation

The serious problem of pharmaceutical and personal care product pollution places great pressure on aquatic environments and human health. Herein, a novel coating photocatalyst was synthesized by adhering Ag-AgCl/WO₃/g-C₃N₄ (AWC) nanoparticles on a polydopamine (PDA)-modified melamine sponge (MS) through a facile layer-by-layer assembly method to degrade trimethoprim (TMP). The formed PDA coating was used for the anchoring of nanoparticles, photothermal conversion, and hydrophilic modification. TMP (99.9%; 4 mg/L) was removed in 90 min by the photocatalyst coating (AWC/PDA/MS) under visible light via a synergistic photocatalytic-photothermal performance route. The stability and reusability of the AWC/PDA/MS have been proved by cyclic experiments, in which the removal efficiency of TMP was still more than 90% after five consecutive cycles with a very little mass loss. Quantitative structure-activity relationship analysis revealed that the ecotoxicities of the generated intermediates were lower than those of TMP. Furthermore, the solution matrix effects on the photocatalytic removal efficiency were investigated, and the results revealed that the AWC/PDA/MS still maintained excellent photocatalytic degradation efficiency in several actual water and simulated water matrices. This work develops recyclable photocatalysts for the potential application in the field of water remediation.

Determination of Asenapine Maleate in Pharmaceutical and Biological Matrices: A Critical Review of Analytical Techniques over the Past Decade

Asenapine maleate is a second-generation atypical antipsychotic agent used in the treatment of schizophrenia, a neuropsychiatric disorder. It is available as a fast-dissolving sublingual tablet to avoid extensive first-pass metabolism with higher bioavailability as compared to oral formulations. Although, the established therapeutic solutions do not sufficiently satisfy the patient's safety and efficacy needs. Thus, the core research emphasis is to investigate strategies to produce novel formulations with enhanced safety and efficacy. This necessitates the development of robust, precise, and accurate methods for quantification of asenapine maleate in different sample matrices. Given the foregoing information, the current analysis concentrates on the different analytical techniques used to assess asenapine maleate in bulk, pharmaceutical formulations, and biological specimens. Reverse-phase HPLC coupled with UV detection is a majorly (nearly 50% of papers investigated) used technique for the estimation of asenapine maleate in formulations. On the other hand, for its quantification in the biological matrix, hyphenated techniques using mass spectrometry are widely used. This critical review reveals different analytical methodologies, including spectrophotometric, chromatographic, capillary electrophoresis techniques reported from 2011 to 2020, for the measurement of asenapine maleate in various sample matrices. The information presented in this review would be useful in future research for robust analytical method development for asenapine maleate utilizing a more scientific and risk-based approach. Also, it would aid to minimize analytical failure as well as method fine-tuning throughout the product life cycle. Further, this review may also direct scientists toward the development of methodologies for green research.

Monitoring photolysis and (solar photo)-Fenton of enrofloxacin by a methodology involving EEM-PARAFAC and bioassays: Role of pH and water matrix

The degradation of enrofloxacin (ENR) by direct photolysis, Fenton and solar photo-Fenton processes has been studied in different water matrices, such as ultra-pure water (MQ), tap water (TW) and highly saline water (SW). Reactions have been conducted at initial pH 2.8 and 5.0. At pH = 2.8, HPLC analyses showed a fast removal of ENR by (solar photo)-Fenton treatments in all studied water matrices, whereas a 40% removal was observed after 120 min of photolysis. However, TOC measurements showed that only solar photo-Fenton was able to produce significant mineralization (80% after 120 min of treatment); differences between ENR removal and mineralization can be attributed to the release of important amounts of reaction by-products. Excitation-emission matrices (EEMs) combined with parallel factor analysis (PARAFAC) were employed to gain further insight into the nature of these by-products and their time-course profile, obtaining a 5-component model. EEM-PARAFAC results indicated that photolysis is not able to produce important changes in the fluoroquinolone structure, in sharp contrast with (solar photo)-Fenton, where decrease of the components associated with fluoroquinolone core was observed. Agar diffusion tests employing E. coli and S, aureus showed that the antibiotic activity decreased in parallel with the destruction of the fluoroquinolone core.