[Gentamycin binding with blood proteins]

An 'in vitro' microbiologic method was employed to follow up the activity of gentamycin diluted in bovine and swine sera and bound to proteins isolated from them, in the course of continuous storing. It was found that the protein solutions of gentamycin retain their activity for one year under refrigerator conditions (4 degrees C), whereas with the freeze-drying of these solutions storage could be effected at room temperature. It was established through the method of balanced dialysis that gentamycin binds with the proteins of swine sera, and to a largest extent with native serum (30 per cent) and to a lower one--with globulins (15--16.2 per cent). The protein complexes of gentamycin proved entirely reversible and the process of binding was shown to have no influence on the minimal bacteriostatic concentration of the antibiotic with regard to Bacillus mycoides HB2.