Sulfadiazine-d4 is intended for use as an internal standard for the quantification of sulfadiazine by GC- or LC-MS. Sulfadiazine is a sulfonamide antibiotic that inhibits the growth of Gram-positive and Gram-negative bacteria.1,2,3,4 It inhibits dihydropteroate synthase (DHPS), which converts a pteridine and 4-aminobenzoic acid to dihydropteroate, an intermediate in folate biosynthesis.1 Sulfadiazine inhibits recombinant P. carinii DHPS (IC50 = 0.19 μM). It is active against clinical isolates of M. tuberculosis (MIC90 = 10 mg/L) and of N. meningitidis (MICs = 5-2,000 mg/L).2,3 Sulfadiazine is also active against A. pleuropneumoniae, S. choleraesuis, S. typhimurium, P. multocida, S. equi, and S. suis (MIC90s = <0.5 mg/ml for all) when used in combination with trimethoprim .4 In vivo, sulfadiazine (40 mg/kg per day) increases survival in a mouse model of lethal T. gondii infection when administered in combination with pyrimethamine .5 Formulations containing sulfadiazine have been used in the treatment of rheumatic fever and various infections, and, in a dual treatment with pyrimethamine, to treat toxoplasmosis.
1.Hong, Y.-L., Hossler, P.A., Calhoun, D.H., et al.Inhibition of recombinant Pneumocystis carinii dihydropteroate synthetase by sulfa drugsAntimicrob. Agents Chemother.39(8)1756-1763(1995) 2.Ameen, S.M., and Drancourt, M.In Vitro Susceptibility of Mycobacterium tuberculosis to Trimethoprim and Sulfonamides in FranceAntimicrob. Agents Chemother.57(12)6370-6371(2013) 3.Wiggins, G.L., McLaughlin, J.V., Bickham, S.T., et al.Susceptibility of Neisseria meningitidis strains from the civilian population to sulfadiazine, penicillin, and rifampinAppl. Microbiol.20(6)893-898(1970) 4.Salmon, S.A., Watts, J.L., Case, C.A., et al.Comparison of MICs of ceftiofur and other antimicrobial agents against bacterial pathogens of swine from the United States, Canada, and DenmarkJ. Clin. Microbiol.33(9)2435-2444(1995) 5.Martins-Duarte, ?.S., de Souza, W., and Vommaro, R.C.Toxoplasma gondii: The effect of fluconazole combined with sulfadiazine and pyrimethamine against acute toxoplasmosis in murine modelExp. Parasitol.133(3)294-299(2013)