[Stability of antibiotics in disks as one of the indicators of their quality].

In connection with the new requirements to the content of antibiotics in discs and a new procedure for the disc labeling stability of antibiotics in discs was studied with the methods of storage under natural conditions and under conditions of accelerated ageing. It was shown that the method of accelerated ageing was not applicable to testing antibiotic stability in discs, since with the use of this method a significant decrease in the antibiotic activity was observed which did not correspond to the real decrease in activity determined with the method of storage under natural conditions. The expiry date of the discs with benzylpenicillin or semisynthetic penicillins was determined to be equal to 1.5 years when stored at 10 degrees C. The expiry date of the discs with thermostable antibiotics was determined to be equal to 3 years when stored at 10 degrees C. Though certain inactivation of the antibiotics was observed, their content in the discs remained within the required limits, i.e. 75-135 per cent of the activity indicated on the label.