References of "Rozet, Eric"
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See detailDetermination of binary polymorphic mixtures of fluconazole using near infrared spectroscopy and X-ray powder diffraction: A comparative study based on the pre-validation stage results
Ziemons, Eric ULg; Bourichi, H.; Mantanus, Jérôme ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2011), 55

The aim of the present study was to develop near infrared (NIR) and X-ray powder diffraction methods (XRPD) able to determine pure crystalline form II of fluconazole in a binary polymorphic mixtures ... [more ▼]

The aim of the present study was to develop near infrared (NIR) and X-ray powder diffraction methods (XRPD) able to determine pure crystalline form II of fluconazole in a binary polymorphic mixtures containing form II and III. In order to give a first performance estimation of both methods, these latters were pre-validated using accuracy profiles, a statistical approach based on β-expectation tolerance intervals. Both methods showed a good trueness, precision and accuracy and their β-expectation tolerance intervals were fully included within the acceptance limits. The comparative study was carried out using statistical analysis based on the work of Bland and Altman. A good agreement between the two methods was demonstrated indicating the interchangeability of NIR method with XRPD method. [less ▲]

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See detailDO PLACEBO BASED VALIDATION STANDARDS MIMIC REAL BATCH PRODUCTS BEHAVIOUR? CASE STUDIES
Bouabidi, A.; Talbi, M.; Bouklouze, A. et al

in Journal of Pharmaceutical & Biomedical Analysis (2011), 55

Analytical methods validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application. Validation usually involves validation standards ... [more ▼]

Analytical methods validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application. Validation usually involves validation standards or quality control samples that are prepared in placebo or reconstituted matrix made of a mixture of all the ingredients composing the drug product except the active substance or the analyte under investigation. However, one of the main concerns that can be made with this approach is that it may lack an important source of variability that come from the manufacturing process. The question that remains at the end of the validation step is about the transferability of the quantitative performance from validation standards to real authentic drug product samples. In this work, this topic is investigated through three case studies. Three analytical methods were validated using the commonly spiked placebo validation standards at several concentration levels as well as using samples coming from authentic batch samples (tablets and syrups). The results showed that, depending on the type of response function used as calibration curve, there were various degrees of differences in the results accuracy obtained with the two types of samples. Nonetheless the use of spiked placebo validation standards was showed to mimic relatively well the quantitative behaviour of the analytical methods with authentic batch samples. Adding these authentic batch samples into the validation design may help the analyst to select and confirm the most fit for purpose calibration curve and thus increase the accuracy and reliability of the results generated by the method in routine application. [less ▲]

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See detailAdvances in validation, risk and uncertainty assessment of bioanalytical methods
Rozet, Eric ULg; Marini Djang'Eing'A, Roland ULg; Ziemons, Eric ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2011), 55

Bioanalytical method validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application in order to trust the critical decisions that ... [more ▼]

Bioanalytical method validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application in order to trust the critical decisions that will be made with them. Even if several guidelines exist to help perform bioanalytical method validations, there is still the need to clarify the meaning and interpretation of bioanalytical method validation criteria and methodology. Yet, different interpretations can be made of the validation guidelines as well as for the definitions of the validation criteria. This will lead to diverse experimental designs implemented to try fulfilling these criteria. Finally, different decision methodologies can also be interpreted from these guidelines. Therefore, the risk that a validated bioanalytical method may be unfit for its future purpose will depend on analysts personal interpretation of these guidelines. The objective of this review is thus to discuss and highlight several essential aspects of methods validation, not only restricted to chromatographic ones but also to ligand binding assays owing to their increasing role in biopharmaceutical industries. The points that will be reviewed are the common validation criteria, which are selectivity, standard curve, trueness, precision, accuracy, limits of quantification and range, dilutional integrity and analyte stability. Definitions, methodology, experimental design and decision criteria are reviewed. Two other points closely connected to method validation are also examined: incurred sample reproducibility testing and measurement uncertainty as they are highly linked to bioanalytical results reliability. Their additional implementation is foreseen to strongly reduce the risk of having validated a bioanalytical method unfit for its purpose. [less ▲]

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See detailTotal Error and Uncertainty: Friends or Foes?
Rozet, Eric ULg; Dewe, Walthere; Rudaz, Serge et al

in Trends in Analytical Chemistry [=TRAC] (2011), 30(5), 797-806

The guidelines ISO 17025 and ISO 15189 aim at improving the quality assurance scheme of laboratories. Reliable analytical results are of core importance due to the critical decisions that are taken with ... [more ▼]

The guidelines ISO 17025 and ISO 15189 aim at improving the quality assurance scheme of laboratories. Reliable analytical results are of core importance due to the critical decisions that are taken with them. Therefore among other topics, these documents require that analytical methods be validated and that laboratories should be able to provide measurement uncertainty of their measured routine results. To evaluate analytical methods fitness of purpose, total error has been and is more and more applied to assess reliability of results generated by analytical methods. However, the ISO requirement to estimate measurement uncertainty seems in opposition with the total error concept, leading to delays in their implementation by laboratories and increased confusion for the analysts. Thus, this article aims at clarifying the divergences between total error and measurement uncertainty, but also to discuss their main similarities and give some emphasise to their implementations. [less ▲]

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See detailApplication of new methodologies based on design of experiments, independent component analysis and design space for robust optimization in liquid chromatography
Debrus, Benjamin ULg; Lebrun, Pierre ULg; Ceccato, Attilio ULg et al

in Analytica Chimica Acta (2011), 691

HPLC separations of an unknown sample mixture and a pharmaceutical formulation have been optimized using a recently developed chemometric methodology proposed by W. Dewé et al. in 2004 and improved by P ... [more ▼]

HPLC separations of an unknown sample mixture and a pharmaceutical formulation have been optimized using a recently developed chemometric methodology proposed by W. Dewé et al. in 2004 and improved by P. Lebrun et al. in 2008. This methodology is based on experimental designs which are used to model retention times of compounds of interest. Then, the prediction accuracy and the optimal separation robustness, including the uncertainty study, were evaluated. Finally, the design space (ICH Q8(R2) guideline) was computed as the probability for a criterion to lie in a selected range of acceptance. Furthermore, the chromatograms were automatically read. Peak detection and peak matching were carried out with a previously developed methodology using independent component analysis published by B. Debrus et al. in 2009. The present successful applications strengthen the high potential of these methodologies for the automated development of chromatographic methods. [less ▲]

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See detailUrinary NGAL measurement : Biological variation and ratio to creatinine
Delanaye, Pierre ULg; Rozet, Eric ULg; Krzesinski, Jean-Marie ULg et al

in Clinica Chimica Acta (2011), 412(3-4), 390

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See detailEvaluating analytical results reliability using a Bayesian probability criterion
Rozet, Eric ULg; Lebrun, Pierre ULg; Boulanger, Bruno ULg et al

Poster (2010, December 02)

In pharmaceutical industries, quantitative analytical methods such as HPLC play a key role. Indeed, the analytical results obtained from them are used to make crucial decisions such as the release of ... [more ▼]

In pharmaceutical industries, quantitative analytical methods such as HPLC play a key role. Indeed, the analytical results obtained from them are used to make crucial decisions such as the release of batches of drugs, the evaluation of safety and efficacy of new drug candidates or the monitoring of patients health. Prior to their routine use, analytical methods are submitted to a stringent validation study where they have to demonstrate that they are fit for their final purpose, i.e. providing accurate result . Typically this demonstration is made by either providing point estimates of systematic error (bias) and random error (variance) or sometimes by providing interval estimates of these statistical parameters at several well defined concentration levels of the target analyte. They are then compared to maximum acceptable levels. More recently, tolerance intervals approaches have been proposed that are evaluated in a similar way at these key concentration levels. However none of these decision approaches allow knowing the probability to obtain accurate results over the whole concentration range of interest. Frequentist approximations have been proposed to estimate this probability but only at the concentration levels experimentally tested and not for the whole range of interest. In this work, a linear hierarchical Bayesian approach is proposed. It takes into account the potential random characteristic of the slope and intercept observed from one analytical run to the other, and also integrates the possible covariance between the parameters. Additionally, heteroscedasticity of the residual variance over the concentration range investigated is taken into account. A situation regularly observed in practice. Finally a reliability profile for the whole concentration range studied is obtained using MCMC sampling. This profile provides the probability (Prel) to obtain accurate results over the full concentration range investigated. This profile is then compared to a minimum reliability probability (Pmin) that will define the valid concentration range of the analytical method. The usefulness of this approach is illustrated through the validation of a bioanalytical method and also compared with a one concentration level at a time frequentist approach derived from tolerance intervals. [less ▲]

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See detailReliable low cost capillary electrophoresis device for drug quality control and counterfeit medicines
Marini Djang'Eing'A, Roland ULg; Rozet, Eric ULg; Montes De Lourdes Aja, Maria et al

in Journal of Pharmaceutical & Biomedical Analysis (2010), 53(5), 1278-1287

The proportion of counterfeit medicines is dramatically increasing these last few years. According to numerous official sources, in some pharmaceutical wholesalers in African countries, the proportion has ... [more ▼]

The proportion of counterfeit medicines is dramatically increasing these last few years. According to numerous official sources, in some pharmaceutical wholesalers in African countries, the proportion has reached 80%. Unfortunately, this situation is far to be improved due to lack of suitable analytical equipment allowing rapid actions of the Regulatory Agencies based on scientific consideration, at affordable cost and all over the drug supply chain. For that purpose, a network group considered that mater by building a low-cost original capillary electrophoresis (CE) equipment equipped with a new deep UV detector based on LED technology. The generic conditions for analysis were investigated: capillary zone electrophoresis (CZE) performed at acidic pH for basic drug molecules (i.e., quinine, highly used as the last antimalarial rampart), basic pH for compounds such as furosemide (a common diuretic drug) and at neutral pH for a well known antibiotic combination, trimethoprim/sulfamethoxazol. To evaluate the ability of the CE equipment for quantification, a full validation and a method comparison study were carried out for the CZE method dedicated to quinine determination. The validation involved the use of accuracy profile and total error concept to monitor the adequacy of the results obtained by the new prototype. The method comparison was based on the Bland and Altman approach by comparing results obtained by the low-cost CE and a conventional set-up. Subsequent validation studies were realized with neutral and acidic drug molecules, each focusing on a single concentration level calibration curve in order to maintain as low as possible the expenses due to reagents and thus the cost of analysis, as important advantages of CE for drug quality control. [less ▲]

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See detailRISK MANAGMENT IN THE VALIDATION OF ANALYTICAL METHODS
Hubert, Philippe ULg; Ziemons, Eric ULg; Mantanus, Jérôme ULg et al

Conference (2010, October)

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See detailTOLERANCE INTERVALS AS CONTROL CHART: COMPARISON TO CLASSIC SHEWHART X̅-R CONTROL CHART
Marini Djang'Eing'A, Roland ULg; Lambert, Véronique; Denooz, Raphael ULg et al

Poster (2010, September)

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See detailDoes placebo based validation standards mimic well real batch products behaviour? A case study
Bouabidi, Abderrahim ULg; Talbi, M.; Bouklouze, A. et al

Poster (2010, September)

Detailed reference viewed: 127 (25 ULg)