Synthesis of [2H6]ceftazidime as a stable isotopically labeled internal standard

Ceftazidime is a third generation cephalosporin antibiotic that has activity against a wide range of Gram-negative and Gram-positive bacterial pathogens, including Escherichia coli and Pseudomonas aeruginosa. Stable isotope-labeled ceftazidime was required for use as an internal standard in LC-MS/MS assays, and a route was developed to make [H-2(6)]ceftazidime in eight steps from the commercially available labeled starting material [H-2(7)]isobutyric acid.