492 research outputs found

    Development and validation of an LC method for the determination of six corticosteroids, salicylic acid and parabens in different pharmaceutical formulations

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    peer reviewedaudience: researcher, professional, student, popularizationMise au point de méthodes d’analyse en vue de l’étude de stabilité des principes actifs dans des formes dermopharmaceutiques dans le cadre de l’établissement d’un Nouveau Formulaire Thérapeutique valid

    Automated method for the determination of a new matrix metalloproteinase inhibitor in ovine plasma and serum by coupling of restricted access material for on-line sample clean-up to liquid chromatography

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    A fully automated liquid chromatographic method was developed for the determination of Ro 28-2653, a new synthetic inhibitor of matrix metalloproteinases (MMPs), in ovine serum and plasma. The method was based on the coupling of a pre-column packed with restricted access material, namely LiChrospher RP-8 ADS (alkyl diol silica), for sample clean-up to an analytical column containing octyl silica stationary phase. One hundred mul of biological sample, to which 2-propanol was automatically added, were injected onto the ADS pre-column, which was then washed with a washing liquid consisting of a mixture of 25 mM phosphate buffer (pH 7.0) and acetonitrile (90: 10; v/v) for 10 min. By rotation of the switching valve, the analyte was then eluted in the back-flush mode with the LC mobile phase composed of a mixture of acetonitrile and 25 mM phosphate buffer (pH 7.0) (57:43; v/v). The UV detection was performed at 395 nm. The main parameters likely to influence the sample preparation technique were investigated. The method was then validated over a concentration range from 17.5 to 1950 ng/mI, the first concentration level corresponding to the lower limit of quantitation. At this concentration level, the mean bias and the R.S.D. value for intermediate precision were -2.4% and 4.2%, respectively. (C) 2004 Elsevier B.V. All rights reserved
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