Studies on the synthesis and antibacterial activity of new carbamoylpyrrolidinylthiocarbapenems

Synthesis and biological properties of new 1beta-methylcarbapenems containing heteroaromatic thioether moiety

The synthesis and biological activities of a series of new 1beta-methylcarbapenems 1a-h having heteroaromatic thioether moiety at C-5 position of pyrrolidine were described. Among these compounds, 1,2,3-thiadiazole derivative 1h showed the most potent antibacterial activity and advanced pharmacokinetics in comparison with meropenem.

Meropenem exists in equilibrium with a carbon dioxide adduct in bicarbonate solution

Evidence is provided for the existence of a second discrete chemical form of meropenem at clinically relevant concentrations prepared from the marketed formulation of the drug. Proton and carbon-13 NMR spectra in D2O, coupled with tandem mass spectroscopy (MS/MS) and cross polarization/magic angle spinning (CP-MAS) NMR experiments, allow structural assignment of the compound as a covalent carbon dioxide adduct of meropenem. This carbon dioxide adduct exists in equilibrium with the free drug in solution and can be observed in the solid state following lyophilization. The equilibrium constant of formation of the adduct (Keq = 20 +/- 8 M-1) was estimated in D2O at 25 degreesC.