NEOSPORIN G.U. Irrigant is a concentrated sterile antibiotic solution to be diluted for urinary bladder irrigation. Each mL contains neomycin sulfate equivalent to 40 mg neomycin base, 200,000 units polymyxin B sulfate, and Water for Injection. The 20-mL multiple-dose vial contains, in addition to the above, 1 mg methylparaben (0.1%) added as a preservative.
Neomycin sulfate, an antibiotic of the aminoglycoside group, is the sulfate salt of neomycin B and C produced by Streptomyces fradiae . It has a potency equivalent to not less than 600 µg of neomycin per mg. The structural formulae are:
Polymyxin B sulfate, a polypeptide antibiotic, is the sulfate salt of polymyxin B1 and B2 produced by the growth of Bacillus polymyxa. It has a potency of not less than 6,000 polymyxin B units per mg. The structural formulae are: