Photostability study of multicomponent drug formulations via MCR-ALS: The case of the hydrochlorothiazide-amiloride mixture

Chemometrics combined with comprehensive two-dimensional gas chromatography-mass spectrometry for the identification of Baijiu vintage

The identification of baijiu vintage is crucial for quality assessment and economic value determination. However, its complex composition and multifaceted influences pose significant technical challenges, necessitating research into its aging mechanisms and the development of related identification methods. This study utilized Chemometrics in conjunction with GC × GC-TOFMS for Baijiu Vintage identification. Data compression achieved a reduction of over 1000-fold without compromising key information, enabling analysis on many samples and get their changing regular in a big matrix by MCR. Subsequently, MCR-ALS facilitated the extraction of physical and chemical meaningful information related to baijiu vintage. Key MCR principal components suitable for qualitative and quantitative assessments were selected using CARS-PLS. The regression model demonstrated errors of less than one year. Furthermore, a PLS-DA model provided 30 MCR principal components as potential markers. The research results provide technical support for baijiu vintage identification and lay the groundwork for studying the changing patterns of flavor compounds in baijiu.

Multivariate Chemometric Comparison of Forced Degradation and Electrochemical Oxidation LC-MS Profiles of Maraviroc

In this study, nine forced degradation products of maraviroc were found using chemometric analysis. This antiretroviral drug was subjected to photolytic, oxidative, as well as neutral, basic and acidic hydrolysis stress conditions. Additionally, its electrochemical transformation on platinum, gold and glassy carbon screen-printed electrodes was examined. This study showed that maraviroc is especially susceptible to UVA, H₂O₂ and electrochemical degradation, while being resistant to neutral and acidic hydrolysis. A cluster analysis showed that the electrochemical transformation, with particular reference to the platinum electrode, is able to partially simulate the forced degradation processes, especially in the context of redox reactions. These findings indicate that the electrochemical methods can be considered as quick and relatively low-cost supplements to the commonly applied forced degradation procedures.

Enhanced degradation of amiloride over Bi2FeNbO7/bisulfite process: Key factors and mechanism

Construction of Bi₂FeNbO₇/bisulfite system for abatement of pharmaceutical residue was achieved. An attempt to synthesize Bi₂FeNbO₇ through hydrothermal technique was confirmed by X-ray diffraction. The magnetic field experiment revealed that Bi₂FeNbO₇ possessed a saturation magnetization of 6.99 emu/g, indicating magnetic attributes of Bi₂FeNbO₇. Scanning electron microscopy images showed that Bi₂FeNbO₇ exhibited regular octahedra in the size of 200-300 nm. In a self-made device, the activation of sodium bisulfite using Bi₂FeNbO₇ for the disposal of amiloride has been carefully explored. The effects of solution pH, sodium bisulfite concentration, Bi₂FeNbO₇ dosage, amiloride concentration, coexisting ions, and water matrix on the performance of Bi₂FeNbO₇/bisulfite system was investigated. The catalytic performance of Bi₂FeNbO₇/bisulfite to degrade amiloride was considerably higher than that of traditional iron oxides. The maximum removal efficiency of amiloride was 97.9% in Bi₂FeNbO₇/bisulfite process. The involvement of Fe might be crucial for activating bisulfite to create active species. The dominating radical in Bi₂FeNbO₇/bisulfite process was identified as SO₃^•‒. With the help of UHPLC/MS/MS, three new degradation products of amiloride were found. Dehalogenation and deamination of amiloride might account for the formation of these transformation products. This work provides a highly efficient Bi₂FeNbO₇/bisulfite process for the disposal of pharmaceutical pollutants in water treatment.

Interaction of letrozole and its degradation products with aromatase: chemometric assessment of kinetics and structure-based binding validation

Letrozole is one of the most prescribed drugs for the treatment of breast cancer in post-menopausal women, and it is endowed with selective peripheral aromatase inhibitory activity. The efficacy of this drug is also a consequence of its long-lasting activity, likely due to its metabolic stability. The reactivity of cyano groups in the letrozole structure could, however, lead to chemical derivatives still endowed with residual biological activity. Herein, the chemical degradation process of the drug was studied by coupling multivariate curve resolution and spectrophotometric methodologies in order to assess a detailed kinetic profile. Three main derivatives were identified after drug exposure to different degradation conditions, consisting of acid-base and oxidative environments and stressing light. Molecular docking confirmed the capability of these compounds to accommodate into the active site of the enzyme, suggesting that the sustained inhibitory activity of letrozole may be at least in part attributed to the degradation compounds.

Coupling of spectrometric, chromatographic, and chemometric analysis in the investigation of the photodegradation of sulfamethoxazole

A workflow is proposed for the study of the photodegradation process of the sulfamethoxazole (SMX) based on the combination of different experimental techniques, including liquid chromatography, mass spectrometry, UV-Visible spectrophotometry, and the treatment of all the analytical data with advanced chemometric methods. SMX, which is one of the most widely used antibiotics worldwide and has been found at remarkable concentrations in various rivers and effluents over all Europe, was degraded in the laboratory under a controlled source of UV radiation, which simulates the environmental solar radiation (Suntest). Kinetic monitoring of the photodegradation process was performed using UV-Visible spectrophotometric measurements and by further Liquid Chromatography with Diode Array Detector and Mass Spectrometry analysis (LC-DAD-MS). Additionally, the acid-base properties were also investigated to see how the pH can affect the speciation of this substance during the photodegradation process. Based on the Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) application, the proposed chemometric method coped with the large amounts of data generated by the different analytical techniques used to monitor the evolution of the photodegradation process. Their simultaneous analysis involved applying a data fusion strategy and an advanced MCR-ALS constrained analysis, which allowed and improved the description of the complete degradation process, detecting the different species of the reaction, and identifying the possible transformation products formed. A total number of six species were resolved in the degradation process of SMX. In addition to the initial SMX, a second species corresponded to a conformational isomer, and the other four species represented different photoproducts, which have also been identified. Furthermore, three different acid-base species of SMX were obtained, and their pK_a values were estimated.

Exploitation of flow-based procedures for reagentless hydrochlorothiazide determination and accelerated degradation studies of pharmaceutical preparations

Drug quality assessment and stress testing are important to ensure both treatment efficacy and patient safety. High performance liquid chromatography may be considered a standard technique for pharmaceutical analysis, showing good precision and accuracy, but it also involves relatively high cost and low analytical frequency. Flow injection analysis presents high sample throughput, lower cost and might be used for selective drug analysis with an appropriate assay and/or detector. In this paper, for the first time, photoreactions promoted by UV radiation were employed for reagentless spectrophotometric determination of hydrochlorothiazide. Optimized parameters led to a linear range of 50 to 500 mg L^-1, estimated limit of detection of 3.0 mg L^-1 and 24 determinations per hour. The use of diluted NaOH solution as a carrier allowed solubilization of hydrochlorothiazide and analysis without organic solvents. The presence of the most common excipients was evaluated and no significant interferences were observed. The results from the analysis of samples by the proposed and by the reference procedures demonstrated accuracy and matching results. The proposed in-line photolysis of the pharmaceutical, performed in 5 min, is a promising alternative to the conventional hydrolytic forced degradation, which requires elevated temperature and prolonged time period. To evaluate the degree of photoconversion, a capillary zone electrophoresis method was developed, which performed well for separations manifesting good analytical frequency and reduced amount of waste. The combination of in-line photodegradation followed by separation by capillary electrophoresis is a promising approach for the stress test of hydrochlorothiazide in pharmaceutical formulations.