mezlocillin mezlocillin mezlocillin is a broad-spectrum penicillin antibiotic. it is active against both gram-negative and some gram-positive bacteria. unlike most other extended spectrum penicillins, it is excreted by the liver, therefore it is useful for biliary tract infections, such as ascending cholangitis. mezlocillinclinical dataahfs/drugs.commicromedex detailed consumer informationpregnancycategory b routes ofadministrationintravenous, intramuscularatc codej01ca10 (who) pharmacokinetic dataprotein binding16–59%metabolismhepatic (20–30%)elimination half-life1.3–4.4 hoursexcretionrenal (50%) and biliaryidentifiers iupac name (2s,5r,6r)-3,3-dimethyl-6--2-phenyl-acetyl]amino]-7-oxo-4-thia-1-azabicycloheptane-2-carboxylic acid cas number51481-65-3 ypubchem cid656511drugbankdb00948 ychemspider570894 yuniioh2o403d1gkeggd05021 ychebichebi:6919 ychemblchembl1731 ycomptox dashboard (epa)dtxsid1023316 echa infocard100.052.013 chemical and physical dataformulac21h25n5o8s2molar mass539.58 g·mol−13d model (jsmol)interactive image smiles o=c(o)3n4c(=o)(nc(=o)(c1ccccc1)nc(=o)n2c(=o)n(s(=o)(=o)c)cc2)4sc3(c)c inchi inchi=1s/c21h25n5o8s2/c1-21(2)14(18(29)30)26-16(28)13(17(26)35-21)22-15(27)12(11-7-5-4-6-8-11)23-19(31)24-9-10-25(20(24)32)36(3,33)34/h4-8,12-14,17h,9-10h2,1-3h3,(h,22,27)(h,23,31)(h,29,30)/t12-,13-,14+,17-/m1/s1 ykey:ypbatnhybcgssn-vwpfqqqwsa-n y (verify) mechanism of action main article: beta-lactam antibiotic like all other beta-lactam antibiotics, mezlocillin inhibits the third and last stage of bacterial cell wall synthesis by binding to penicillin binding proteins. this ultimately leads to cell lysis. susceptible organisms gram-negative bacteroides spp., including b. fragilis enterobacter spp. escherichia coli haemophilus influenzae klebsiella species morganella morganii neisseria gonorrhoeae proteus mirabilis proteus vulgaris providencia rettgeri pseudomonas spp., including p. aeruginosa serratia marcescens gram-positive enterococcus faecalis peptococcus spp. peptostreptococcus spp. synthesis mezlocillin synthesis: mezlocillin can be made in a variety of ways including reaction of ampicillin with chlorocarbamate 1 in the presence of triethylamine. chlorocarbamate 1 itself is made from ethylenediamine by reaction with phosgene to form the cyclic urea followed by monoamide formation with methanesulfonyl chloride and then reaction of the other nitrogen atom with phosgene and trimethylsilylchloride. the closely related analogue azlocillin is made in essentially the same manner as mezlocillin. but with omission of the methylation step.