Neomycin and Polymyxin B Sulfates and Bacitracin Zinc with Hydrocortisone (Neomycin Sulfate / Polymyxin B Sulfate / Bacitracin Zinc / Hydrocortisone Acetate Ophthalmic) - Description and Clinical Pharmacology

Sterile

Rx only

DESCRIPTION

Neomycin and polymyxin B sulfates and bacitracin zinc with hydrocortisone acetate ophthalmic ointment is a sterile antimicrobial and anti-inflammatory ointment for ophthalmic use. Each gram contains: neomycin sulfate equivalent to 3.5 mg neomycin base, polymyxin B sulfate equivalent to 10,000 polymyxin B units, bacitracin zinc equivalent to 400 bacitracin units, hydrocortisone acetate 10 mg (1 %), in a white petrolatum and mineral oil base.

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 var Tracy. It has a potency of not less than 40 bacitracin units per mg. The structural formula is:

Hydrocortisone acetate, Pregn-4-ene-3,20-dione,21-(acetyloxy)-11,17-dihydroxy-,(11β)–, is an anti-inflammatory hormone. Its structural formula is:

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 ug 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:

CLINICAL PHARMACOLOGY

Corticosteroids suppress the inflammatory response to a variety of agents and they probably delay or slow healing. Since corticosteroids may inhibit the body's defense mechanism against infection, concomitant antimicrobial drugs may be used when this inhibition is considered to be clinically significant in a particular case. When a decision to administer both a corticosteroid and antimicrobials is made, the administration of such drugs in combination has the advantage of greater patient compliance and convenience, with the added assurance that the appropriate dosage of all drugs is administered. When each type of drug is in the same formulation, compatibility of ingredients is assured and the correct volume of drug is delivered and retained. The relative potency of corticosteroids depends on the molecular structure, concentration, and release from the vehicle.

Microbiology

The anti-infective components in neomycin and polymyxin B sulfates and bacitracin zinc with hydrocortisone acetate ophthalmic ointment are included to provide action against specific organisms susceptible to it. Neomycin sulfate and polymyxin B sulfate are active in vitro against susceptible strains of 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 (see INDICATIONS AND USAGE).