Bacitracin preparation

Most polymyxin B sold for human use in the United States is in dermatological, otic, and ophthalmic preparations that usually contain one or more other spectmm extending antibacterials such as bacitracin, neomycin sulfate [1404-04-2], C23H4gNg023, linear gramicidin, oxytetracycline [79-57-2],... 

Other Derivatives of SaUcylic Acid. p-Aminosalicylic acid and its salts have been used in the treatment of tuberculosis. / -Aminosalicylic add can be prepared by the caiboxylation of in-amiuoplienol. Metliylene-5,5-disalicylic acid, produced by heating two parts salicylic acid with 1-1.5 parts of 30-40 wt % formaldehyde in the presence of an add catalyst, is used as an intermediate in the production of bacitracin me thy le ne di salicy la te. 

Polymyxin B is effective against many gramnegative bacteria, including E. coli, Klebsiella, and Salmonella. Systemic administration of this drug, however, is often associated with extreme nephrotoxicity. Hence, this agent is used primarily for the treatment of local, superficial infections of the skin, eyes, and mucous membranes. When applied topically for these conditions, adverse reactions are relatively rare. Polymyxin B is often combined with other antibiotics such as bacitracin and neomycin in commercial topical preparations. 

R. G. Bell, Preparative HPLC separation and isolation of bacitracin components and their relationship to microbiological activity, J. Chromatogr., 590 163 (1992). 

Topical ophthalmic preparations containing bacitracin (Tables 11-5, 11-6, and 11-7) are effective for treatment of superficial eye infections. Bacitracin is especially useful for treating staphylococcal blepharitis, because most staphylococci remain sensitive to this antibiotic (see Table 11-1). 

Taste acceptability is a particular issue with oral liquid dosage forms, lozenges, and chewable tablets. The problem may be overcome by the preparation of poorly soluble salts. Thus the bitterness of erythromycin and of bacitracin may be ameliorated by use of the estolate (lauryl sulfate) and zinc salts, respectively. Propoxaphene may be taste masked by forming the napsylate, the solubility of which may be further reduced and the taste improved by adding a common-ion salt such as sodium or calcium napsylate. 

Bacitracin zinc in pharmaceutical preparations New approach to quarternary ammonium compounds Pharmacology of choline theophylllinate Methemoglobinemia resulting from absorption of nitrates (From RefJ. )... 

Neomycin is not usually administered parenter-ally to animals because of nephrotoxicity and ototoxicity. Only 3% of a dose of neomycin is absorbed following p.o. administration it is, therefore, used in the therapy of coliform enteritis in small and large animals. It is available as tablets, boluses and water additives, in many different combinations with antibiotics, corticosteroids and anticholinergic agents. It can also be used to decrease nitrogenous waste production by the normal gastrointestinal flora in animals with hepatic encephalopathy. Neomycin is not absorbed through the skin, so it is frequently utilized as the antibacterial constituent in ophthalmic formulations (especially in combination with bacitracin and polymyxin B) and in preparations for the treatment of otitis externa in small animals. 

Neomycin currently is available in many brands of creams, ointments, and other products alone and in combination with polymyxin, bacitracin, other antibiotics and a variety of corticosteroids. There is no evidence that these topical preparations shorten the time required for healing of wounds or that those containing a steroid are more effective. 

Bacitracin is available in ophthalmic and dermatologic ointments the antibiotic also is available as a powder for the preparation of topical solutions. The ointments are applied directly to the involved surface one or more times daily. A number of topical preparations of bacitracin, to which neomycin or polymyxin or both have been added, are available, and some contain the three antibiotics plus hydrocortisone. For open infections such as infected eczema and infected dermal ulcers, the local application of the antibiotic may be of some help in eradicating sensitive bacteria. Bacitracin rarely produces hypersensitivity. Suppurative conjunctivitis and infected comeal ulcer respond well to the topical use of bacitracin when caused by susceptible bacteria. Bacitracin has been used with limited success for eradication of nasal carriage of staphylococci. Oral bacitracin has been used with some success for the treatment of antibiotic-associated diarrhea caused by C. difficile. Serious nephrotoxicity results from the parenteral use of bacitracin. Hypersensitivity reactions rarely result from topical application. 

It may cause allergic contact dermatitis, especially on disrupted skin. Bacitracin inhibits staphylococci, streptococci, arul gram-positive bacilli. Polymyxin B is active against aerobic gram-negative bacilli. Bacitracin arul polymyxin B are combined in a number of over-the-counter preparations. 

An example of a solid-phase synthesis of a side chain-to-C-terminal cyclic peptide has also been published (Scheme 11). Lee et al. [78] exploited the side-chain resin attachment principle and Kates protocol to prepare bacitracin A, a cyclic dodecapeptide antibiotic, cycZo(H-A hi-Leu-DGlu-Ile-... 

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