title: Forced degradation study of racecadotril: Effect of co-solvent, characterization of degradation products by UHPLC-Q-TOF-MS/MS, NMR and cytotoxicity assay.
abstract: Racecadotril, an enkephalinase inhibitor, was subjected to hydrolysis (acidic and alkaline), oxidation, photolysis and thermal stress, as per ICH specified conditions. The drug showed extensive degradation under acidic, basic hydrolysis and oxidative stress conditions whereas, it was stable under other stress conditions. A total of seven degradation products (DPs) were observed. The chromatographic separation was optimized on Acquity HSS Cyano (100×2.1mm, 1.8μ) column using 0.1% formic acid and acetonitrile as mobile phase in gradient mode. Six DPs were characterised by LC-MS/MS and DP1 by GC-MS. The major DPs (DP 2 and DP 5) were isolated and characterised by NMR. This is a typical case of degradation where co solvent methanol reacts with racecadotril leading to the formation of pseudo DPs, DP 6 and DP 5. Interestingly the MS/MS spectra of protonated drug, DP 4 and DP 7 showed product ions which were formed due to intramolecular benzyl migrations. In vitro cytotoxic activity studies on isolated DP 2 and DP 5 revealed that the former has no cytotoxic nature, whereas the latter has potential pulmonary and hepatic toxicity.
authors.affiliation: Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research, Hyderabad (NIPER-H), Balanagar, Hyderabad 500037 Telangana, India.
authors.forename: Vishnuvardhan
authors.initials: V
authors.lastname: Chiguru
authors.affiliation: Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Hyderabad (NIPER-H), Balanagar, Hyderabad 500037 Telangana, India.
authors.forename: Allakonda
authors.initials: A
authors.lastname: Lingesh
authors.affiliation: Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research, Hyderabad (NIPER-H), Balanagar, Hyderabad 500037 Telangana, India; National Center for Mass Spectrometry, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607 Telangana, India. Electronic address: srini@iict.res.in.
authors.forename: Srinivas
authors.initials: S
authors.lastname: R
authors.affiliation: Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research, Hyderabad (NIPER-H), Balanagar, Hyderabad 500037 Telangana, India. Electronic address: satish.niperhyd@gov.in.
authors.forename: Satheeshkumar
authors.initials: S
authors.lastname: N
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004355:Drug Stability; D005561:Formates / Q000737:chemistry; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D010084:Oxidation-Reduction; D010782:Photolysis; D012997:Solvents / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000379:methods; D015244:Thiorphan / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D005561:Formates; D012997:Solvents; C030544:formic acid; C049331:racecadotril; D015244:Thiorphan; C032159:acetonitrile
keywords: Benzyl-benzyl interactions; Cytotoxic assay; Forced degradation; GC–MS; LC–MS/MS