EXTRACTION OF AMINOGLYCOSIDE ANTIBIOTICS WITH REVERSE MICELLES

The reverse micelle system of sodium di-2-ethylhexyl phosphate was use d to extract aminoglycoside antibiotics, neomycin and gentamicin. The aminoglycosides can be efficiently extracted into a reverse micelle so lution, and the antibiotics extracted into the micelle phase can readi ly be recovered back to a divalent cation aqueous solution, such as Ca 2+. The transfer efficiency, %E, is heavily dependent on pH and salt c oncentration in the aqueous feed solution. %E decreases drastically wi th pH in the pH range 8.5-11, and declines with increasing (NH4)(2)SO4 concentration. A simple transfer mechanism was proposed which suggest s that the antibiotic molecules were extracted into the inner water co res of reverse micelles through attractive electrostatic interaction d uring forward transfer. In backward transfer, the antibiotics loaded i n the micelle phase are released back to an aqueous phase through brea king up of the reverse micelles by using divalent cation solutions. Th e model is supported by the results of dynamic light scattering and in fra-red spectroscopy study.