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Liquid chromatography (LC) and capillary electrophoresis (CE) methods were developed to perform the determination of residual sodium in mother liquors and successive washes of an active pharmaceutical ingredient (API). The addition of sodium chloride to the product solution results in rapid and complete crystallization of the API. The LC method was coupled to evaporative light scattering detection (ELSD) while the CE approach was based on indirect UV detection. Both methods were fully validated. Selectivity, response function, trueness, precision, accuracy, linearity and limits of detection (LOD) and quantification (LOQ) were the criteria investigated. The LC-ELSD method was found to be more sensitive than the CE/indirect UV approach. The methods were found to be valid over concentration ranges of 62-500 and 235-1500 ppm for the LC and the CE methods, respectively. Both methods were compared and used for the determination of actual samples coming from different batches of the same API chemical synthesis. (c) 2006 Elsevier B.V. All rights reserved.

Five antibiotics belonging to the cephalosporins and penicillins groups have been irradiated: anhydrous ampicilline acid, amoxicilline acid trihydrate, cefuroxime sodium salt, cloxacilline sodium salt monohydrate and ceftazidime pentahydrate. ESR studies have been carried out, showing the influence of irradiation and storage parameters on the nature and concentration of the free radicals trapped. These results may be used to detect an irradiation treatment on such pharmaceuticals. (C) 2000 Elsevier Science Ltd. All rights reserved.

We propose to detect the use of gamma-rays in order to radiosterilize ampicillin by UV absorption spectroscopy. The UV absorption results are verified by comparison with HPLC-diode array analysis. The sensitivity is excellent (10(-6) M). The wavelengths in the range from 287 to 335 nm are characteristics of radiolysis related substances. It is possible to use this range of wavelengths to detect the radiolysis of ampicillin with an usual UV spectrophotometer.

Tnermoluninescence signals from ionized pharmaceuticals, as ampicillin, can be easily distinguished fi om those of untreated samples, even two years after radiolysis; thus they could be applied to the detection of a radio-sterilization treatment.

Trapped radicals are used to detect the sterilization of solid drugs by gamma rays. However, some drugs present trapped radicals after U.V. irradiation. The quantitative E.S.R. measurements are different between U.V. photolysis and gamma radiolysis.

Can the absence of increased toxicological danger in irradiated foods be applied with confidence to drugs ? The World Health Organization stated that up to 10 kGy there is no toxicological hazard. However, even if the irradiated drugs meet official standards, it would have to be established that any traces of radiolysis product formed are not toxic. All the tests from PHARMACOPEIA are not appropriate to detect the radiolysis and new physicochemical tests have to be used. Chromatographic detection of the radiosterilization of antibiotics may be advantageously used when the pharmaceuticals are not radio-resistant. The main obstacle to pratical application is the low sensitivity of the detectors in liquid-liquid chromatography, a re-irradiation of the suspected samples will be necessary after preliminary chromatographic studies.