Neomycin

Neomycin

Brand Names : Mycifradin; Myacyne; Fradiomycin; Neomin; Neolate; Neomas; Nivennycin; Pimavecort; Vonamycin Powder V.

Neomycin is a mixture of three CHN H2 substances A, B and C isolated h from Steptomyces fradiae by counter  current distribution.


 The neomycin A (neamine) is a basic disaccharide which is a common degradation product of neomycins  B and C. These neomycins B and C consist of four carbohydrate units and differ only in the configuration of the amino-methyl group in the neosamine ring linked streptainine to the ribose unit. Framycetin consists mainly of neomycin B with not more than 3% of neomycin C. Neamine may be obtained by methanolysis of neomycins B and C during which the glycosidic link between the deoxystreptamine and D-Ribose is broken. Therefore, Neosamine is a combination of deoxystreptamine and neosamine C linked glycosidically at the 4-position of deoxystreptamine. Neomycin B differs from neomycin C by the nature of the sugar attached terminally to D-ribose. The sugar neosamine B differs from neosamine C in its stereochemistry.It has been suggested recently that both the diamino sugars in neomycin C have the L-idose configuration and that the glycosidic link is beta in one attached to D-ribose.





Neomycin complex is an amorphous base soluble in water, methanol and acidified alcohol; practically insoluble in common organic solvents.


Neomycin B (Brand Names : Framycetin; Enterfram; Gramygen; Soframycin; Actilin; Antibiotique EF 185) yields on hydrolysis neamine and neobisamine B.

Neomycin C yields on hydrolysis in e and neobiosamine.

Neomycin B sulphate (Brand Names: Bykomycin, Fraquinol; Myacine; Neosulf. Neomix; Neobrettin; Tuttomycin) is an amorphous white, tasteless powder. It is soluble in water (6.3 in 1); slightly soluble in alcohols; practically insoluble in acetone. ether and chloroform. Aqueous solutions are fairly stable at pH 2 to 9. Highly purified preparations are very stable to alkali and unstable to acids.



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