Macrolide antibiotics distribution

Another basic drug where minor structural modification results in a dramatic increase in volume of distribution is the macrolide antibiotic, azithromycin. The traditional agent in this class is erythromycin, which contains one basic nitrogen, in the sugar side-chain. 

Azithromycin. Azithromycin is another recently developed macrolide antibiotic. After oral administration on an empty stomach, azithromycin is rapidly absorbed and widely distributed throughout the body. Because azithromycin has an extended half-life, once-daily dosing is effective and encourages patient compliance. 

A variety of non-mammalian (l-4)GalTs are widely distributed in Nature. For example, a cell free extract from S. hygroscopicus has been used to galacto-sylate macrolide antibiotics [69]. Notably, a number of solid-phase galactosyla-tions of immobilized substrates have also been probed successfully [70-72]. 

A Merck group was interested in the introduction of a basic amino group into the avermectin molecule [228]. This should change its physical properties, make it more polar, and result in a different tissue distribution. In addition, most of the anti-bacterially active macrolide antibiotics contain an aminosugar. After suitable protection and deprotection, reductive amination of a 4"-oxo intermediate gave the 4"-amino-4"-deoxy analogue as the major reaction product (Scheme 19). Since they also had observed better activity in the southern armyworm assay for certain monosaccharides, they prepared their 4 -amino derivatives as well as the... 

Among the many antibiotics isolated from the actinomycetes isthe group of chemically related compounds called the mac-mlides. In I9S0, picromycin, the first of this group to be identified as a macrolide compound, was first reported. In 1952. erythromycin and carbomycin were reported us new antibiotics, and they were followed in subsequent years by other macrolides. Currently, more than 40 such compounds ate known, and new ones are likely to appear in the future. Of all of these, only two, erythromycin and oleandomycin, have been available consistently for medical use in the United States. In recent years, interest has shifted away from novel macrolides isolated from soil samples (e.g.,. spiramycin, josamycin, and rosamicin), all of which thus far have proved to be clinically inferior to erythromycin and semisynthetic derivatives of erythromycin (e.g., clarithromycin and azithromycin), which have superior pharmacokinetic properties due to their enhanced acid stability and improved distribution properties. 

Managaki S, Murata A, Takada H, Tuyen BC, Chiem NH (2007) Distribution of macrolides, sulfonamides, and trimethoprim in tropical waters Ubiquitous occurrence of veterinary antibiotics in the Mekong Delta. Environ Sci Technol 41 8004-8010... 

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