Contribution à l'amélioration de modèles pour estimer les paramètres de stabilité de substances médicamenteuses :cas particuliers de l'acide acétylsalicylique

Doctorat en sciences pharmaceutiquesinfo:eu-repo/semantics/nonPublishe

A new method for pH-profile data treatment: Non linear parameter estimation

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An original algorithm for non linear parameter estimation of drug stability data

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Incorporating batch effects in the estimation of drug stability parameters using an Arrhenius model

The nonlinear estimation of drug stability parameters (energy of activation E(a) and shelf-life t(Y)) by conventional approaches employs equations relating drug content determination C at time t and temperature T. The identification procedures lead to the determination of only one initial drug content C0 for several different experiments. However, it is well known that because of experimental concentration variation or of intentional modification of the experimental schedule, there are as many initial drug contents as experiments. For these reasons, a method which takes into account batch effects is proposed to determine stability parameters and also all initial drug contents C(0j) where j is the index of experiment in one step. This method is more accurate from a statistical viewpoint and is suitable for data treatment in pharmaceutical industries where the initial drug content of each batch entering the stability program can be checked a posteriori. The application of this method is shown on real kinetic data from the hydrolysis of acetylsalicylic acid (ASA). Copyright (C) 1999 Elsevier Science B.V.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Stability parameter estimation at ambient temperature from studies at elevated temperatures

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Chromatographic determination of 8-oxo-7,8-dihydro-2'-deoxyguanosine in cellular DNA: A validation study

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Improved kinetic parameter estimation in pH-profile data treatment

Statistical problems in temperature stability parameter estimation have been the subject of many papers whereas statistics in, pH-profile parameter estimation have focused little attention. However, the conventional two step method used in data treatment in both cases leads to identical statistical problems. The aim of this study is then to introduce a method that improves statistics in pH-profile parameter estimation. A one step non-linear method that takes into account the errors in drug content determination is proposed. A mathematical relationship between drug content C, pH and time t is tested. The proposed method allows the estimation of the specific kinetic constants and the dissociation constant (pK(a)) in a single run. The most likely experimental initial drug contents C(0j), where j is the index of a given experiment, are also determined. This approach that takes into account all relevant experimental information for the estimation of kinetic parameters is more rigorous from a statistical viewpoint than the classical two step methods. Kinetic data from acetylsalicylic acid (ASA) hydrolysis was used for the tests. (C) 2000 Elsevier Science B.V.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Determination of groundwater mercury (II) content using a disposable gold modified screen printed carbon electrode

Mercury (II) measurements were performed thanks to a newly developed electrochemical method using a disposable gold modified screen printed carbon electrode. The method has a wide dynamic range (1-100 μg/L), a good accuracy and a limit of detection in compliance with WHO standards. The application of the method to several groundwater samples made it possible to identify, for the first time, mercury content higher than the recommended WHO standard value in a gold mining activity area in the northern part of Burkina Faso. The accuracy of the assay was checked by ICP/MS.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Home-based practicies of complementary foods improvement are associated with better height-for-age z score in rural Burkina Faso

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Validation of gentamicin congeners using HPLC with electrochemical detection: Comparison with fluorimetric detection

OPA is often used as an off-line derivatisation agent for fluorimetric detection in gentamicin analysis. As, in general, electrochemical detection is more sensitive than fluorimetric detection, the analysis of gentamicin as its OPA derivatives by high-performance liquid chromatography and electrochemical detection is proposed. The derivatisation procedure is that described by the European pharmacopoeia. The method allows not only the detection of all major gentamicin congeners C1, C1A, C2A and C2, but also of other minor unidentified components. A full validation of the method is presented and comparison is made with fluorimetric detection. A good linearity is found for the four congeners within the dynamic ranges 1-50 μg ml -1 for electrochemical detection and 4-80 μg ml-1 for fluorimetric detection. Both methods presented good accuracy and fidelity, although electrochemical detection is more sensitive than fluorimetric detection. The electrochemical detection method presented in this work appears to be a good alternative to the fluorimetric and pulsed electrochemical detection methods. © 2004 Published by Elsevier SAS on behalf of Académie des Sciences.SCOPUS: ar.jinfo:eu-repo/semantics/publishe