Chromatographic analysis of neomycin. Isolation and identification of minor components.

The presence of a number of minor components was demonstrated in commercial samples of neomycin by column chromatography on a weakly acidic ion-exchange resin (Amberlite CG-50). Some of these components were isolated by ion-exclusion chromatography and identified. The identification was based on chromatographic and nmr data and on mass spectrometry of volatile derivatives. Thesequence of elution from the Amberlite column was : paromamine, mono-N-acetyl-neamine (LP-A), paromomycin II, a diamino-dideoxyhexosyl-myo-inositol (component G), paromomycin I, mono-N-acetylneomycin C (LP-C), neamine, mono-N-acetylneomycin B (LP-B), neomycin C and neomycin B. The LP-B fraction also contained a component (K) whose gross structure corresponds to a neomycin, in which the neosamine C linked to the deoxystreptamine subunit is missing. The presence of the components LP-A, G and K has not previously been reported.