Neomycin and Polymyxin B Sulfates
Solution for Irrigation, USP
NOT FOR INJECTION
Neomycin and Polymyxin B Sulfates Solution for Irrigation 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, inactive ingredient: sulfuric acid. 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 mcg 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:
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 mcg/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 Neomycin and Polymyxin B Sulfates Solution for Irrigation 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.