Neosporin®

Ophthalmic solution, 10 mL plastic squeeze bottle with controlled drop tip, neomycin sulfate equivalent to 1.75 mg base per mL, polymyxin B sulfate 10,000 units per mL, gramicidin 0.025 mg per mL

Three bactericidal agents with overlapping spectra: neomycin, an aminoglycoside, binds ribosomal RNA and causes misreading of the bacterial genetic code, halting protein synthesis; polymyxin B interacts with membrane phospholipids to increase permeability in gram-negatives; gramicidin forms channels through the lipid bilayer that make the membrane permeable to inorganic cations in gram-positives. Labeled activity covers Staphylococcus aureus, streptococci including Streptococcus pneumoniae, Escherichia coli, Haemophilus influenzae, Klebsiella-Enterobacter species, Neisseria species, and Pseudomonas aeruginosa, but coverage of Serratia marcescens is stated to be inadequate.