A strategy for evaluation of isotopic enrichment and structural integrity of deuterium labelled compounds by using HR-MS and NMR.

Determining the purity of deuterium labelled compounds is important due to the increasing use of these compounds in mass spectrometry (MS) based quantitative analyses for targeting metabolic flux, reducing toxicity, confirming reaction mechanisms during synthesis, predicting enzyme mechanisms, and enhancing the efficacy of drugs, in quantitative proteomics, and also as internal standards. In the present study, a strategy using liquid chromatography electrospray ionization high resolution mass spectrometry (LC-ESI-HR-MS) and nuclear magnetic resonance (NMR) spectroscopy was proposed to determine the isotopic enrichment and structural integrity of deuterium labelled compounds. The proposed strategy involves recording full scan MS, extracting and integrating isotopic ions, and calculating the isotopic enrichment of the desired labelled compounds. NMR analysis confirms structural integrity or positions of labelled atoms and can provide insights into the relative percent isotopic purity. This strategy was used to evaluate the isotopic enrichment and structural integrity of in-house synthesized compounds as well as a series of commercially available deuterium labelled compounds. The % isotopic purity for labelled compounds of a benzofuranone derivative (BEN-d2), tamsulosin-d4 (TAM-d4), oxybutynin-d5 (OXY-d5), eplerenone-d3 (EPL-d3), and propafenone-d7 (PRO-d7) was calculated and found to be 94.7, 99.5, 98.8, 99.9, and 96.5, respectively. All the samples were run in triplicate and the results were observed to be reproducible.

Evaluation of anticardiolipin antibodies in tobacco users and non-tobacco users with severe chronic periodontal disease.

AIMS: Many studies have proven that b2-glycoprotein-I-dependent anticardiolipin is elevated in periodontal diseases. Systemic lupus erythematosus and antiphospholipid syndrome, which are usually associated with high antiphospholipid antibodies, are more prone to adverse pregnancy outcomes and cardiovascular sequelae. Therefore, the aim of the present study is to evaluate IgG, IgM anticardiolipin antibodies in tobacco users and non-tobacco users with severe chronic periodontal disease. MATERIALS AND METHODS: Based on the Armitage classification, 2000, 40 severe periodontitis (group D) (mean clinical attachment loss greater than 2.5 mm) male patients were selected for the study with the age range of 35-65 years and good general health from the Department of periodontics, SRM Kattankulathur Dental College, Chennai. They were classified as smokers (20 subjects) and non-smokers (20 subjects). Blood samples were collected and IgG, IgM antibodies were semi-quantitatively analyzed by enzyme-linked immunosorbent assay. The data thus collected were statistically analyzed by independent student's t-test. RESULTS: Results showed that smokers with severe periodontitis exhibited marked increase in anticardiolipin IgG, IgM compared to non-smokers. They showed a positive correlation and statistical significance (P < 0.0001) between mean clinical attachment loss and IgG and IgM values. CONCLUSIONS: Results showed a rise in anticardiolipin antibodies in smokers with severe periodontitis, which indicates that these patients are more prone to coronary heart disease.

Phenylimidazoles as potent and selective inhibitors of coagulation factor XIa with in vivo antithrombotic activity.

Novel inhibitors of FXIa containing an (S)-2-phenyl-1-(4-phenyl-1H-imidazol-2-yl)ethanamine core have been optimized to provide compound 16b, a potent, reversible inhibitor of FXIa (Ki = 0.3 nM) having in vivo antithrombotic efficacy in the rabbit AV-shunt thrombosis model (ID50 = 0.6 mg/kg + 1 mg kg(-1) h(-1)). Initial analog selection was informed by molecular modeling using compounds 11a and 11h overlaid onto the X-ray crystal structure of tetrahydroquinoline 3 complexed to FXIa. Further optimization was achieved by specific modifications derived from careful analysis of the X-ray crystal structure of the FXIa/11h complex. Compound 16b was well tolerated and enabled extensive pharmacologic evaluation of the FXIa mechanism up to the ID90 for thrombus inhibition.