The active metabolite of leflunomide, A77 1726, increases proliferation of human synovial fibroblasts in presence of IL-1β and TNF-α

Quantitative determination of cyanoacetic acid content in teriflunomide drug substance by ion chromatography using conductivity detector

Background

The current study focuses on the development and validation of an analytical method for quantifying cyanoacetic acid (CAA) in teriflunomide drug substance using a high-performance ion chromatography (IC) with cation suppressed conductivity detection (TFM). Water was used as the diluent for preparing the sample solution, which was injected into a standard chromatographic device with 250 mm, 4.0 mm ID, and 5.0 μm particle size Metrosep A Supp 5 Ion exchange column and a suppressed conductivity detector. At a flow rate of 0.6 mL min−1 and a temperature of 40 °C, the mobile phase was delivered in an isocratic mode.

Results

CAA and TFM had retention times of 12.78 and 15.82 min, respectively. CAA has a limit of detection (LOD) of 33 μg/g and a limit of quantification (LOQ) of 101 μg/g, respectively. For LOD and LOQ accuracy, the percentage RSD of CAA is 1.7 and 1.2, respectively. The average CAA recovery percentage was found to be between 98.6 and 100.1%. With a value of 0.9998, the calibration curve yielded an excellent linear correlation coefficient for CAA. According to the ICH guidelines, all verification parameters are within the range, indicating that the system is stable.

Conclusion

The elution time and run time in the currently developed ion chromatography analytical method have been reduced, demonstrating that the method is cost-effective and generally accepted, as well as simple and functional, and can be used in routine quality control tests in the industry.

Multiple sclerosis - the remarkable story of a baffling disease

Multiple sclerosis has always been an enigma to its sufferers, their families, medical investigators, and clinicians. For many centuries, there have been attempts to understand its causes and nature, and to discover treatment methods. In the Middle Ages, the disease was claimed to be sent directly from God. A significant development in exploring multiple sclerosis took place in the 19th century, when Jean-Martin Charcot and his colleagues distinguished the disease, precisely described its symptoms, attempted to explain its pathophysiology, and introduced the first methods of symptomatic treatment. The 20th century was a period of discovery and development of diagnostic techniques, such as cerebrospinal fluid analysis, evoked potentials, and magnetic resonance imaging as well as an era of introducing steroid therapy for acute treatment. Currently, the dynamic development of disease modifying therapy and neuroimaging can be observed. The paper aims to delve into the remarkable history of multiple sclerosis by focusing on the earliest case reports and discovery of the disease and exploring its nature, diagnostic methods, and treatment.

Comprehensive study of the organic-solvent-free CDI-mediated acylation of various nucleophiles by mechanochemistry

Acylation reactions are ubiquitous in the synthesis of natural products and biologically active compounds. Unfortunately, these reactions often require the use of large quantities of volatile and/or toxic solvents, either for the reaction, purification or isolation of the products. Herein we describe and discuss the possibility of completely eliminating the use of organic solvents for the synthesis, purification and isolation of products resulting from the acylation of amines and other nucleophiles. Thus, utilisation of N,N'-carbonyldiimidazole (CDI) allows efficient coupling between carboxylic acids and various nucleophiles under solvent-free mechanical agitation, and water-assisted grinding enables both the purification and isolation of pure products. Critical parameters such as the physical state and water solubility of the products, milling material, type of agitation (vibratory or planetary) as well as contamination from wear are analysed and discussed. In addition, original organic-solvent-free conditions are proposed to overcome the limitations of this approach. The calculations of various green metrics are included, highlighting the particularly low environmental impact of this strategy.

Metabolism studies of a small-molecule tumor necrosis factor-alpha (TNF-α) inhibitor, UTL-5b (GBL-5b)

UTL-5b is an anti-inflammatory and anti-arthritic small-molecule tumor necrosis factor-alpha inhibitor and a structural analogue of the anti-arthritic drug, leflunomide. Leflunomide is known to be metabolized to teriflunomide, but the metabolites of UTL-5b have not been reported. The objective of this study was to investigate whether UTL-5b has a similar metabolic behavior as leflunomide. Preliminary studies showed that when exposed to microsomes in vitro with or without NADPH, UTL-5b disappeared within 30 min. To further investigate the microsomal metabolism, liquid chromatography-ultraviolet (LC-UV) and LC/tandem mass spectrometry (LC-MS/MS) were employed to, respectively, monitor the microsomal metabolites and identify the structure of the metabolites using LC-full scan MS and LC combined with multiple-ion monitoring MS. Fragmentation determination was analyzed by two types of scans: product ion scans and precursor ion scan. The in vitro microsomal treatment of UTL-5b resulted in two major metabolites: 5-methylisoxazole-3-carboxylic acid and 2-chloroaniline. Thus, the in vitro metabolic behavior of UTL-5b appears to be different from that of leflunomide in that the isoxazole ring is cleaved.