Antibiotic Potency and Resistance: A Critical Review of Analytical and Microbiological Methodologies

Antibiotics are essential chemotherapeutic agents that inhibit or destroy pathogenic microorganisms, and their development from ancient natural remedies to the discovery of penicillin in 1928 revolutionized modern medicine. Multiple major classes, including β-lactam, macrolide, tetracycline, quinolone, aminoglycoside, sulfonamide, glycopeptide, and oxazolidinone, remain central to treating bacterial infections, making accurate assessment of their quality crucial. This review summarizes key analytical methods used for determining antibiotic potency and quantifying drug levels in pharmaceutical and biological matrices. Spectroscopic techniques provide simple and cost-effective evaluation, while chromatographic methods such as RP-HPLC, UPLC, TLC and HPTLC offer high sensitivity and specificity. Because chemical assays measure potency but not biological activity, critical microbiological parameters minimum inhibitory and bactericidal concentration, mutation-prevention concentration, and related indicators provide deeper insight into bacterial susceptibility and resistance mechanisms. The review also addresses the growing challenge of antimicrobial resistance, driven by misuse and overuse of antibiotics, and outlines current methodologies such as MIC, MBC, and susceptibility testing for detecting resistance across bacterial strains. Overall, the article emphasizes the need for integrated analytical and microbiological approaches to ensure accurate antibiotic evaluation and support effective therapeutic outcomes.