Abstract
Microbiological bioassay, using sensitive microbial indicator, commonly used in quality control and research activities for the determination of the potency of antimicrobial agents. This method depends on the biological inhibitory activity of the tested antimicrobial agent on the growth of suitable microbial indicator in comparison to reference standard. The current study aimed to follow up the potency of three of the most commonly prescribed antimicrobial agents namely, amikacin, ceftriaxone, and ciprofloxacin in various commercial pharmaceutical preparations. The 5 X 1 microbiological bioassay in presence of Staphylococcus aureus ATCC 6538P strain, as a sensitive indicator, was used to evaluate the potency of the tested antimicrobial agents. It was observed that the products decomposition rates varied throughout test intervals; however, the potency of all products remained within the range established by the US Pharmacopeia (USP) by the end of the study. In conclusion, microbiological bioassay using Staphylococcus aureus ATCC 6538P standard strain is appropriate for the assessment of amikacin, ceftriaxone, and ciprofloxacin, in different commercial antimicrobial products, and can be routinely applied in their quality control.