"Mycitracin", until 1997 when that name was acquired by Johnson & Johnson. Some people have allergic reactions to neomycin, so a "double antibiotic ointment" is sold without it, containing only bacitracin and polymyxin B: one such example is Polysporin branded product. A "Plus" variant of the ointment exists that adds the analgesic pramoxine, but uses the cheap, simple, long-lasting, but heavier petroleum jelly base, common to many over-the-counter topicals. The latest version of this analgesic formulation, a high-absorption cream, excludes bacitracin because it is unstable in such a base. Active ingredients The three main active ingredients in Neomycin are neomycin sulfate, polymyxin B sulfate, and bacitracin zinc. One of the main components is neomycin sulfate, which is a type of antibiotic discovered in 1949 by microbiologist Selman Waksman at Rutgers University. Neomycin belongs to the aminoglycoside class of antibiotics and fights against Gram positive and gram negative bacteria. The antibiotic is often used to prevent risk of bacterial infections. Aminoglycosides work by binding to bacterial RNA and changing the ability to produce proteins while exerting little to no effect on DNA. Thus, neomycin kills bacteria as a result of irregular protein production in the bacterial cell. When the cell can no longer produce the correct proteins, its membrane becomes damaged. As a result of damaged membrane, the affected bacterial cells die, and the infection is prevented or limited. Like neomycin, polymyxin B is an antibiotic. Polymyxin B forms holes in the bacterial cell wall causing the internal cellular components to leak out, resulting in cell death. Pramoxine is used to temporarily reduce pain from burns, insect bites, and minor cuts. It works like an anesthetic by decreasing the permeability of neuron membranes. As a result, pain neurons in the area have difficulty sending signals (or signals are blocked entirely), resulting in numbness. In some countries bacitracin is replaced with gramicidin. History There is no exact date as to when the antibacterial ointment was invented, but it was used as early as the 1950s. This antibiotic ointment was patented in the United States on August 27, 1951. References External links Combination antibiotics Polypeptide antibiotics Wikipedia medicine articles ready to translate