DESCRIPTION
CORTISPORIN Ointment (neomycin and polymyxin B sulfates, bacitracin zinc, and hydrocortisone ointment, USP) is a topical antibacterial ointment. Each gram contains: neomycin sulfate equivalent to 3.5 mg neomycin base, polymyxin B sulfate equivalent to 5,000 polymyxin B units, bacitracin zinc equivalent to 400 bacitracin units, hydrocortisone 10 mg (1%), and white petrolatum, qs.
Neomycin sulfate is the sulfate salt of neomycin B and C, which are produced by the growth of Streptomyces fradiae Waksman (Fam. Streptomycetaceae). It has a potency equivalent of not less than 600 µg of neomycin standard per mg, calculated on an anhydrous basis. The structural formulae are:
Polymyxin B sulfate is the sulfate salt of polymyxin B1 and B2, which are produced by the growth of Bacillus polymyxa (Prazmowski) Migula (Fam. Bacillaceae). It has a potency of not less than 6,000 polymyxin B units per mg, calculated on an anhydrous basis. The structural formulae are:
Bacitracin zinc is the zinc salt of bacitracin, a mixture of related cyclic polypeptides (mainly bacitracin A) produced by the growth of an organism of the licheniformis group of Bacillus subtilis (Fam. Bacillaceae). It has a potency of not less than 40 bacitracin units per mg. The structural formula is:
Hydrocortisone, 11β,17,21-trihydroxypregn-4-ene-3, 20-dione, is an anti-inflammatory hormone. Its structural formula is:
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CLINICAL PHARMACOLOGY
Corticoids suppress the inflammatory response to a variety of agents and they may delay healing. Since corticoids may inhibit the body's defense mechanism against infection, a concomitant antimicrobial drug may be used when this inhibition is considered to be clinically significant in a particular case.
The anti-infective components in the combination are included to provide action against specific organisms susceptible to them. Polymyxin B sulfate, bacitracin zinc, and neomycin sulfate together are considered active against the following microorganisms: Staphylococcus aureus, streptococci, including Streptococcus pneumoniae, Escherichia coli, Haemophilus influenzae, Klebsiella-Enterobacter species, Neisseria species, and Pseudomonas aeruginosa.
The product does not provide adequate coverage against Serratia marcescens.
The relative potency of corticosteroids depends on the molecular structure, concentration, and release from the vehicle.
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