June 2008, Sunnyvale, CA—Dionex announces a simplified, rapid method for determining N-methylpyrrolidine (NMP) in the antibiotic cefepime. Application Note 199: Determination of N-Methylpyrrolidine in Cefepime Using a Reagent-Free Ion Chromatography System describes the use of a Reagent-Free™ IC system with Eluent Generation (RFIC-EG™ system) and suppressed conductivity detection for the determination of NMP in cefepime hydrochloride and cefepime for injection. This new method takes approximately three hours less than the United States Pharmacopeia (USP) method and has far lower detection limits. Cefepime is one of the most highly prescribed broad spectrum antibiotics. NMP is formed by degradation of cefepime, and is toxic in high doses. The USP sets a limit of 0.3% NMP in cefepime. The current USP method uses a nitric acid/ acetonitrile eluent and direct conductivity detection. The low pH of nitric acid can increase cefepime degradation, and nonsuppressed conductivity detection has very high detection limits. The new method uses an electrolytically generated MSA gradient without the organic mobile phase required by the USP method, which simplifies eluent preparation and method development. This new method also uses suppressed conductivity detection, which yields detection limits generally an order of magnitude lower than nonsuppressed conductivity. The method's 0.001% limit of quantitation easily allows detection of the 0.3% limit set in the USP method. Dionex (NASDAQ:DNEX) is a global leader in the manufacturing and marketing of liquid chromatography and extraction systems, consumables, and software for chemical analysis. The Company's systems are used worldwide in environmental analysis and by the life sciences, chemical, petrochemical, food and beverage, power generation, and electronics industries. Our expertise in applications and instrumentation helps analytical scientists to evaluate and develop pharmaceuticals, establish environmental regulations, and produce better industrial products.
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