Effectiveness of Biological Assays as an Alternative Method to Determine the Potency of Antibiotics: A Review

Abstract

In this review, chemical and biological assays performed in the pharmaceutical industry to determine the potency and bioactivity of antibiotics are discussed. Though commonly employed chemical methods can measure the potency of antibiotics, inefficiency to estimate the bioactivity is one of their major limitations. Due to their sensitivity and cost-effectiveness, common microbiological assays can serve as alternative methods. Several factors like doses of antibiotics, homogeneity of agar medium, inoculum concentration, chemical composition of agar media, size and solubility of samples or drug molecules, pH, relative humidity and exposure time can influence microbiological assays. Based on specific requirement and experimental targets, agar diffusion assays are designed focusing on their costs, errors, accuracy and simplicity. To avoid the misuse and overuse of antibiotics that leads to drug-resistance, parameters like zone of inhibition, minimum inhibitory concentration, minimum bactericidal concentration, mutation prevention concentration and critical concentration are also conversed in this study. Finally, microbiological and high-performance liquid chromatography methods were specifically compared for their sensitivity, accuracy and assessment of biological activity with minimal cost. Due to their advantages and disadvantages, parallel use of both bioassays and chemical methods are suggested to precisely determine the potency of antibiotics.