Identification and synthesis of metabolites of the new 4.5-dihydroisoxazol-5-carboxamide derivate Authors

• Main Authors: Alexander L. Khokhlov (Author), Ilya I. Yaichkov (Author), Mikhail A. Alexeev (Author), Mikhail K. Korsakov (Author), Anton A. Shetnev (Author), Sergey A. Ivanovsky (Author), Nikita N. Volkhin (Author), Sergey S. Petukhov (Author), Elena A. Vasilyeva (Author)
• Format: Book
• Published: Belgorod National Research University, 2024-06-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.18413/rrpharmacology.10.482; 2658-381X
• Keywords: 4.5-dihydroisoxazol-5-carboxamide derivative; biotransformation; par-2 inhibitor; hplc-ms/ms; hydrolysis; Therapeutics. Pharmacology; RM1-950
• Source: Research Results in Pharmacology, Vol 10, Iss 2, Pp 83-95 (2024)

Introduction: 3-(2-butyl-5-chloro-1H-imidazole-4-yl)-N-[4-methoxy-3-(trifluoromethyl)phenyl]-4,5-dihydro-1,2-oxazole-5-carboxamide is new antirheumatic drug. It is necessary to identify and synthesize the biotransformation products for its complete pharmacokinetic study. Materials and Methods: A biotransformation study was carried out by intraperitoneal administration of the drug to Wistar rats and Soviet Chinchilla breed rabbits. Animal blood sampling was performed before the injection and 0.5 h, 1 h, 2 h, 4 h, 24 h after the injection of the investigated compound. The samples were immediately centrifuged for plasma separation. Urine was simultaneously collected from rats before the administration and at intervals of 0-2 h, 2-4 h, 4-6 h, 6-24 h after administration, faeces - before administration and at intervals of 0-12 h and 12-24 h after administration. The samples were analyzed by HPLC-MS/MS after immediate preparation by adding acetonitrile. Results and Discussion: 3-(2-butyl-5-chloro-1H-imidazole-4-yl)-4,5-dihydro-1,2-oxazole-5-carboxylic acid and 4-methoxy-3-(trifluoromethyl)aniline - hydrolysis products of the active substance were found during the analysis of plasma, urine and fecal samples. The 4,5-dihydro-1,2-oxazole-5-carboxylic acid derivative has been synthesized. The second metabolite is a raw material for production of active pharmaceutical substance. During comparative tests, no significant difference between the retention times, ratio areas of chromatographic peaks at the main MRM-transitions and mass spectra of these metabolites on chromatograms of standard and animal samples was found, which indicates the correct identification of biotransformation products. Conclusion: The studied drug undergoes biotransformation by hydrolysis to form two main metabolites: 3-(2-butyl-5-chloro-1H-imidazole-4-yl)-4,5-dihydro-1,2-oxazole-5-carboxylic acid and 4-methoxy-3-(trifluoromethyl)aniline. The structure of the metabolites was confirmed by comparison with the synthesized standard samples using HPLC-MS/MS.