Evaluation of in-vivo and in-vitro microbiological methods for testing the efficacy of parenteral antibiotics: A Review

Antibiotics are available as innovators and generics. An innovator or branded drug is a medicine that is discovered, developed and marketed by a pharmaceutical company which also holds the patent for that drug. Generics only become available after the patent on the innovator expires. Generic drugs are required to have the same active ingredient, strength, dosage form, and route of administration as the innovator product. Generics should be bioequivalent to the innovator and when used, should have the same efficacy and safety profile. This is crucial for parenteral antibiotics because according to the World Health Organization and U.S. Food and Drug Administration criteria, parenteral generic products do not need to provide evidence for in-vivo bioavailability or bioequivalence before they can be marketed. Published evidence shows that there is a disparity in the efficacy of different generic antibiotic products. In-vitro microbiological methods of efficacy testing have been recognized as a standardized and cost-effective approach to clarify doubts regarding the efficacy of generic parenteral antibiotics. However, in-vitro methods used alone, might not be a good measurement of antibiotic efficacy as several studies have shown disparities between in-vitro and in-vivo efficacy of parenteral antibiotics.