Antimicrobials & Antibiotic Resistance

Analytical strategies for Antimicrobials & Antibiotics

The analysis of antibiotic susceptibility disks by high-pressure liquid chromatography (HPLC) methods are presented for the potency determination of mecillinam, ampicillin, carbenicillin, and cephalotjiin alone and in various combinations. Good agreement between HPLC and microbiological data is observed for potency determinations with recoveries of greater than 95%. Relative standard deviations of lower than 2% are recorded for each HPLC method. HPLC methods offer improved accuracy and greater precision when compared to the standard microbiological methods of analysis for susceptibility disks. The most popular analytical methods for the determination of beta-lactams are the chromatographic ones, including high performance liquid-chromatography (HPLC) and thin layer chromatography (TLC).

HPLC offers high sensitivity and separation efficiency, establishing itself as the first choice method for the analysis of beta-lactams; however it is expensive and requires sophisticated equipment. TLC is a less expensive and less complicated chromatographic procedure, which can be successfully used, in the preliminary screening of pharmaceutical substances. In modern analysis, TLC is usually used as a separation method, which establishes the presence or absence of beta-lactam antibiotics above a defined level of concentration.