Synercid® (quinupristin and dalfopristin powder for injection) I.V., a streptogramin antibacterial agent for intravenous administration, is a sterile lyophilized formulation of two semisynthetic pristinamycin derivatives, quinupristin (derived from pristinamycin I) and dalfopristin (derived from pristinamycin IIA) in the ratio of 30:70 (w/w).
Quinupristin is a white to very slightly yellow, hygroscopic powder. It is a combination of three peptide macrolactones. The main component of quinupristin (> 88.0%) has the following chemical name: N-[(6R,9S,10R,13S,15aS,18R,22S,24aS )-22-[p-(dimethylamino)benzyl]-6-ethyldocosahydro-10,23-dimethyl-5,8,12,15,17,21,24-heptaoxo-13-phenyl-18-[[(3S )-3-quinuclidinylthio] methyl]-12H-pyrido[2,1-f ]pyrrolo-[2,1-l ][1,4,7,10,13,16] oxapentaazacyclononadecin-9-yl]-3-hydroxypicolinamide.
The main component of quinupristin has an empirical formula of C53H67N9O10S, a molecular weight of 1022.24 and the following structural formula:
Dalfopristin is a slightly yellow to yellow, hygroscopic, powder. The chemical name for dalfopristin is: (3R,4R,5E,10E,12E,14S,26R,26aS )-26-[[2-(diethylamino)ethyl]sulfonyl]-8,9,14,15,24,25,26,26a-octahydro-14-hydroxy-3-isopropyl-4,12-dimethyl-3H-21,18-nitrilo-1H,22H-pyrrolo[2,1-c ][1,8,4,19]-dioxadiazacyclotetracosine-1,7,16,22(4H,17H )-tetrone.
Dalfopristin has an empirical formula of C34H50N4O9S, a molecular weight of 690.85 and the following structural formula: