Interaction of kanamycin A and kanamycin B with phospholipids

It has been suggested that the aminoglycoside drugs are ototoxic because they contain amine groups that interact with membrane phospholipids. The interaction of kanamycin A and kanamycin B with vesicles containing various phospholipids was assessed from studies of vesicle aggregation and of the fluorescence of the probes 1-anilino-8-naphthalene sulfonic acid (ANS) and 1,6-diphenyl-1,3,5-hexatriene (DPH) added to the system. Kanamycin B, with 5 amino groups, showed a stronger interaction with the acidic phospholipids than kanamycin A, with only 4 amino groups. The evidence indicated that the interaction was an ionic one involving the charged groups of both components with penetration of the hydrocarbon interior of the bilayers. Of all the phospholipids tested polyphosphoinositide showed the greatest ability to interact with the kanamycins, supporting the proposal that interaction with this phospholipid may be the basis of the ototoxicity of aminoglycosides.