Also on the market this year is Besifloxacin Hydrochloride (USAN) which is marketed as Besivance, approved on May 28th. Besifloxacin is a fluoroquinolone antimicrobial indicated for the treatment of bacterial conjunctivitis, and competes against other fluoroquinolones for the ophthalmic treatment of bacterial infections. Besifloxacin has activity against Gram-positive and Gram-negative bacteria and acts through inhibition of both bacterial DNA gyrase and topoisomerase IV. Besifloxacin is known to be active against various Corynebacterium, Haemophilus, Moraxella, Staphylococcus and Streptococcus spp. Besifloxacin is a small molecule drug (Molecular Weight of 393.8 g.mol-1 for Besifloxacin itself, and 430.3 g.mol-1 for the HCl salt), is Rule-of-Five compliant and is delivered as an ophthalmic suspension. Besifloxacin has a plasma half-life is of 7 hours. Recommended dosage is one drop instilled in the affected eye(s) 3 times a day, four to twelve hours apart, for 7 days. The full prescribing information is here.
The structure (+)-7[(3R)-3-aminohexahydro-1H-azepin-1-yl]-8-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid) contains both an amine and a carboxylic acid functional group, and so will normally exist as a zwitterion. Overall, Besifloxacin is a rigid molecule with few rotatable bonds. The fluoroquinolone class of antibiotics is quite extensive, and is named after the fluro-substituted, fused six-six ring structure at the center of the molecule containing a nitrogen and also the aryl-ketone (the 'one' part of the name).
Besifloxacin Canonical SMILES: N[C@@H]4CCCCN(c3c(F)cc2c(=O)c(C(=O)O)cn(C1CC1)c2c3Cl)C4 Besifloxacin InChI: InChI=1S/C19H21ClFN3O3/c20-15-16-12(18(25)13(19(26)27)9-24(16)11-4-5-11)7-14(21)17(15)23-6-2-1-3-10(22)8-23/h7,9-11H,1-6,8,22H2,(H,26,27) Besifloxacin InChIKey: QFFGVLORLPOAEC-UHFFFAOYSA-N Besifloxacin CAS registry: 141388-76-3 Besifloxacin ChemDraw: Besifloxacin.cdx