NEOSPORIN® G.U. Irrigant Sterile (neomycin sulfate–polymyxin B sulfate solution for irrigation)
NOT FOR INJECTION
Description
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:
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Clinical Pharmacology
After prophylactic irrigation of the intact urinary bladder, neomycin and polymyxin B are absorbed in clinically insignificant quantities. A neomycin serum level of 0.1 µg/mL was observed in three of 33 patients receiving the rinse solution. This level is well below that which has been associated with neomycin-induced toxicity.
When used topically, polymyxin B sulfate and neomycin are rarely irritating.
Microbiology: The prepared NEOSPORIN G.U. Irrigant Sterile solution is bactericidal. The aminoglycosides act by inhibiting normal protein synthesis in susceptible microorganisms. Polymyxins increase the permeability of bacterial cell wall membranes. The solution is active in vitro against
Escherichia coli
Staphylococcus aureus
Haemophilus influenzae
Klebsiella and Enterobacter species
Neisseria species, and
Pseudomonas aeruginosa.
It is not active in vitro against Serratia marcescens and streptococci.
Bacterial resistance may develop following the use of the antibiotics in the catheter-rinse solution.
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