cefapirin cefapirin cefapirin (inn, also spelled cephapirin) is an injectable, first-generation cephalosporin antibiotic. it is marketed under the trade name cefadyl. production for use in humans has been discontinued in the united states. cefapirinclinical dataahfs/drugs.cominternational drug namesmedlineplusa601206routes ofadministrationintravenous, intramuscularatc codej01db08 (who) qg51aa05 (who) qj51db08 (who)legal statuslegal status us: ℞-only identifierscas number21593-23-7 ypubchem cid30699drugbankdb01139 ychemspider28486 yunii89b59h32vnkeggd07636 ychebichebi:554446 ychemblchembl1599 ycomptox dashboard (epa)dtxsid9022784 echa infocard100.040.409 chemical and physical dataformulac17h17n3o6s2molar mass423.46 g·mol−13d model (jsmol)interactive image smiles o=c2n1/c(=c(\cs12nc(=o)csc3ccncc3)coc(=o)c)c(=o)o inchi inchi=1s/c17h17n3o6s2/c1-9(21)26-6-10-7-28-16-13(15(23)20(16)14(10)17(24)25)19-12(22)8-27-11-2-4-18-5-3-11/h2-5,13,16h,6-8h2,1h3,(h,19,22)(h,24,25)/t13-,16-/m1/s1 ykey:uqllwwbdsuhneb-czuorrhysa-n y (verify) it also has a role in veterinary medicine as metricure, an intrauterine preparation, and combined with prednisolone in mastiplan, an intramammary preparation. both are licensed in cattle. synthesis cephapirin synthesis: u.s. patent 3,422,100 u.s. patent 3,503,967 u.s. patent 3,578,661 in one of the syntheses, 7-aminocephalosporanic acid (7-aca) is reacted with bromoacetyl chloride to give the amide. the halo group is then displaced by 4-thiopyridine.