References of "Marini Djang'Eing'A, Roland"
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See detailEvaluation of the quantitative performances of Supercritical Fluid Chromatography : from method development to validation
Dispas, Amandine ULg; Lebrun, Pierre ULg; Ziemons, Eric ULg et al

in Journal of Chromatography. A (in press)

Recently, the number of papers about SFC increased drastically but scientists did not truly focus their work on quantitative performances of this technique. In order to prove the potential of UHPSFC, the ... [more ▼]

Recently, the number of papers about SFC increased drastically but scientists did not truly focus their work on quantitative performances of this technique. In order to prove the potential of UHPSFC, the present work discussed about the different steps of the analytical life cycle of a method: from development to validation and application. Moreover, the UHPSFC quantitative performances were evaluated in comparison with UHPLC, which is the main technique used for quality control in the pharmaceutical industry and then could be considered as a reference. The methods were developed using Design Space strategy, leading to the optimization of robust method. In this context, when the Design Space optimization shows guarantee of quality, no more robustness study is required prior to the validation. Then, the methods were geometrically transferred in order to reduce the analysis time. The UHPSFC and UHPLC methods were validated based on the total error approach using accuracy profile. Even if UHPLC showed better precision and sensitivity, UHPSFC method is able to give accurate results in a dosing range larger than the 80–120% range required by the European Medicines Agency. Consequently, UHPSFC results are valid and could be used for the control of active substance in a finished pharmaceutical product. Finally, UHPSFC validated method was used to analyse real samples and gave similar results than the reference method (UHPLC). [less ▲]

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See detailDevelopment of a liquid chromatographic method for thesimultaneous quantification of curcumin, -arteether,tetrahydrocurcumin and dihydroartemisinin. Application to lipid-based formulations
Memvanga Bondo, Patrick; Mbinze Kindenge, Jérémie ULg; Rozet, Eric ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2014), 88(-), 447-456

A liquid chromatographic method was developed for the simultaneous separation of curcumin, B-arteether, tetrahydrocurcumin and dihydroartemisinin based on the design of experiments and the design space ... [more ▼]

A liquid chromatographic method was developed for the simultaneous separation of curcumin, B-arteether, tetrahydrocurcumin and dihydroartemisinin based on the design of experiments and the design space methodology. The influence of the percentage of organic modifier, flow rate of the mobile phase and column temperature on the analytes separation was investigated. The optimal chromatographic separation was achieved on a C18 column (125 mm × 4 mm, 5 µm) using an isocratic elution with a mobile phase consisting of methanol:ammonium acetate (pH 4; 10 mM) (80/20, v/v) at a flow rate of 0.45 ml/min and a column temperature of 32.5◦C. This method was then validated for simultaneous quantification of curcumin and B -arteether contained in lipid-based formulations taking into account the B -expectation tolerance interval for the total error measurement. Finally, the suitability of the proposed liquid chromatographic method for routine analysis of curcumin and B -arteether loaded in lipid-based formulations has been proven. [less ▲]

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See detailValidation data treatment
Marini Djang'Eing'A, Roland ULg; Rozet, Eric ULg; Hubert, Philippe ULg

Learning material (2013)

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See detailApplication of an innovative design space optimization strategy to thedevelopment of LC methods for the simultaneous screening of antibiotics to combat poor quality medicines
Mbinze Kindenge, Jérémie ULg; Dispas, Amandine ULg; Lebrun, Pierre ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2013), 85

The poor quality of medicines is a crucial problem of public health. Therefore, it is important to haveanalytical tools to attend decisions of the legal authorities while combating this offense. In this ... [more ▼]

The poor quality of medicines is a crucial problem of public health. Therefore, it is important to haveanalytical tools to attend decisions of the legal authorities while combating this offense. In this context,the main objective of this study was to develop generic methods able to trace, screen and determineseveral antibiotics and common associated molecules by mean of liquid chromatographic techniques.For that purpose, an innovative Design Space optimization strategy was applied, targeting 16 antibioticsand 3 beta-lactamase inhibitors. The robustness of the developed method allowed using its use in anenvironment where operational factors such as temperature are not easy to control and eased its trans-fer to Ultra High Performance Liquid Chromatography. To demonstrate its ability to quantify the targetedmolecules, the developed and transferred method was fully validated for two active ingredients com-monly used in association, sulbactam and ceftriaxone, using the accuracy profile as decision tool. Basedon this successful step, the method was then used for the quantitative determination of these two activeingredients in three pharmaceutical brands marketed in the Democratic Republic of Congo. Two out ofthe three pharmaceutical products did not comply with the specifications [less ▲]

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See detailNiveaux du plomb sanguin, du plomb urinaire, de l’acide δ-aminolévulinique et des porphyrines urinaires chez les personnes vivant à Kinshasa, R.D. Congo : une étude pilote de biosurveillance
Mputu Malolo, Corneille-Liévin; Ndelo di Phanzu, Josaphat; Marini Djang'Eing'A, Roland ULg et al

Conference (2013, October 18)

Objectives: Existing naturally in the earth’s crust, Lead is a widely used heavy metal. It is an environment toxicant that may deleteriously affect nervous, hematopoietic, skeletal, renal, endocrine and ... [more ▼]

Objectives: Existing naturally in the earth’s crust, Lead is a widely used heavy metal. It is an environment toxicant that may deleteriously affect nervous, hematopoietic, skeletal, renal, endocrine and reproductive systems. Lead is classified in its inorganic form as possible human carcinogen (group 2A) by IARC. Exposure to lead in the environment continues to be a serious public health problem for all ages. Children are particularly susceptible to lead poisoning. They absorb more lead from their environment and their developing central nervous systems are vulnerable to the toxicant. During the last twenty years, important measures of public health were undertaken in several countries to decrease lead exposure. In the best of our knowledge, this is not the case in D.R. Congo. A study indicated a relatively important lead impregnation of the Kinshasa population (mean 120 μg/L). However, there have been no reported studies in the evaluation of the relationship between urinary lead, urinary δ-aminolevulinic acid (δ-AlaU) and urinary porphyrins and lead blood level in Congolese people. This is the aim of this study targeting at first people living in Kinshasa. Methods: Blood lead and urinary lead levels were measured using inductively coupled plasma mass spectrometry. The Bio-Rad ALA/PBG by Column Test and spectrophotometer method were used to quantify the concentration of δ-Ala in urine. The separation of porphyrins was carried out by HPLC coupled with fluorescence detector. Results: 37% of studied population presented blood lead levels above the 100 μg/L threshold (geometric mean: 133.29 μg/L) with a higher concentration in women than in men (140.30 μg/L vs 130.78 μg/L). 50% of children (0-17 years) presented blood lead levels above the 100 μg/L threshold and 43% of the same population presented blood lead levels above 50 μg/L as accepted nowadays in US. In the adult population, some targeted occupations were found to be associated with high blood lead. A small correlation was observed between urinary lead and blood lead, but no correlation was noticed between δ-AlaU and Porphyrins with lead blood levels. Conclusion: This study confirmed a relatively important Pb impregnation of the Kinshasa population and the existence of a major public health issue requiring corrective actions and the implementation of an appropriate regulation. Also, urinary lead, urinary δ-Ala and urinary porphyrins seems to not to be sensitive markers for monitoring exposure to lead. [less ▲]

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See detailA New Method for Quality by Design Robust Optimization in Liquid Chromatography
Debrus, Benjamin ULg; Lebrun, Pierre ULg; Rozet, Eric ULg et al

in LC-GC Europe (2013), -(-), -

A new method to optimize liquid chromatography (LC) methods using a Quality by Design (QbD) approach is presented. This method is based on the use of design of experiments (DOE) and independent component ... [more ▼]

A new method to optimize liquid chromatography (LC) methods using a Quality by Design (QbD) approach is presented. This method is based on the use of design of experiments (DOE) and independent component analysis (ICA) to accurately estimate the modelled responses (that is, the retention times at the beginning, the apex, and the end) of each peak, even for coeluted peaks. The modelling of these responses usesmultiple linear regressions, while the propagation of the error affecting the responses and coming from the models is carried out by Monte Carlo simulation. The design space is determined as the region of assay factors where the probability to reach baseline-resolved peaks is higher than the desired level of quality. This method was applied to the optimization of the separation of nine compounds in a mixture, yielding the design space and the demonstration of robustness of the method. Finally, the method was validated. [less ▲]

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See detailFalsification des médicaments: mythe ou réalité ?
Marini Djang'Eing'A, Roland ULg; Fillet, Marianne ULg; Vancauwenberghe, Roy et al

Conference (2013, April 24)

La santé publique est de nos jours minée par la problématique des médicaments falsifiés ou de qualité inférieure, avec plusieurs conséquences sanitaires, économiques voire professionnelles. On estime à 7 ... [more ▼]

La santé publique est de nos jours minée par la problématique des médicaments falsifiés ou de qualité inférieure, avec plusieurs conséquences sanitaires, économiques voire professionnelles. On estime à 7% la part du marché pharmaceutique mondial que représenterait ce fléau; l’Afrique, l’Asie et de nombreux pays d'Amérique latine étant les régions les plus touchées avec plus de 30% de médicaments falsifiés. D’après l'OMS, plus de 50% des médicaments achetés à partir des sites internet illégaux sont contrefaits, annihilant très fortement les chances de succès thérapeutique. Ces médicaments viennent dans la plupart des cas des pays asiatiques et de l’Eurasie. Le trafic de faux médicaments est un crime contre l'humanité qui représente environ 50 milliards de dollars par an (10-15 % de plus que le marché de la drogue). Au travers de deux leçons, la situation de la falsification des médicaments sera présentée au grand public dans le but de le sensibiliser à ce fléau. La première leçon présentera la situation en Europe avec un accent sur la Belgique. La problématique du droit à la propriété intellectuelle et de l’encadrement législatif sera abordée, ainsi que la falsification des médicaments modernes et des phytomédicaments, ces derniers étant utilisés par plus de 40% de la population en Europe et aux Etats-Unis. Dans la seconde leçon sera abordée la situation vécue en Afrique. L’approvisionnement en médicaments de qualité par le partage de l’information sera présenté ainsi que les moyens analytiques à la disposition de ce continent pour combattre ce fléau. Des membres du Département de Pharmacie de l’Université de Liège, de l’Agence Fédérale des Médicaments et des Produits de Santé ainsi que du programme QUAMED (Quality Medicines for All) feront partager leur expérience sur cette question d’une brûlante actualité.  [less ▲]

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See detailBlood lead, urinary lead, urinary δ-aminolevulinic acid and urinary porphyrins levels among people living in kinshasa, D.R. Congo : a pilot biomonitoring study
Mputu Malolo, Corneille-Liévin; Ndelo di Phanzu, Josaphat; Marini Djang'Eing'A, Roland ULg et al

in Acta Clinica Belgica (2013), 68(6), 475

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See detailUsefulness of Information Criteria for the Selection of Calibration Curves
Rozet, Eric ULg; Ziemons, Eric ULg; Marini Djang'Eing'A, Roland ULg et al

in Analytical Chemistry (2013), 85

The reliability of analytical results obtained with quantitative analytical methods is highly dependant upon the selection of the adequate model used as calibration curve. To select the adequate response ... [more ▼]

The reliability of analytical results obtained with quantitative analytical methods is highly dependant upon the selection of the adequate model used as calibration curve. To select the adequate response function or model the most used and known parameter is the determination coefficient R². However it is well known that it suffers many inconvenient, such as leading to overfitting the data. A solution proposed is to use the adjusted determination coefficient R²adj that aims at reducing this problem. However there is another family of criteria that exists to allow the selection of an adequate model: the information criteria AIC, AICc and BIC. These criteria have rarely been used in analytical chemistry to select the adequate calibration curve. This works aims at assessing the performance of the statistical information criteria as well as R² and R²adj for the selection of an adequate calibration curve. They are applied to several analytical methods covering liquid chromatographic methods as well as electrophoretic ones involved in the analysis of active substances in biological fluids or aimed at quantifying impurities in drug substances. In addition, Monte-Carlo simulations are performed to assess the efficacy of these statistical criteria to select the adequate calibration curve. [less ▲]

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See detailMethodology for the Validation of Analytical Methods involved in Uniformity of Dosage Units tests
Rozet, Eric ULg; Ziemons, Eric ULg; Marini Djang'Eing'A, Roland ULg et al

in Analytica Chimica Acta (2013), 760

Validation of analytical methods is required prior to their routine use. In addition, the current implementation of the Quality by Design (QbD) framework in the pharmaceutical industries aims at improving ... [more ▼]

Validation of analytical methods is required prior to their routine use. In addition, the current implementation of the Quality by Design (QbD) framework in the pharmaceutical industries aims at improving the quality of the end products starting from its early design stage. However, no regulatory guideline or none of the published methodologies to assess method validation propose decision methodologies that effectively take into account the final purpose of developed analytical methods. In this work a solution is proposed for the specific case of validating analytical methods involved in the assessment of the Content Uniformity or Uniformity of Dosage Units of a batch of pharmaceutical drug products as proposed in the European or US pharmacopoeias. This methodology uses statistical tolerance intervals as decision tools. Moreover it adequately defines the Analytical Target Profile of analytical methods in order to obtain analytical methods that allow to make correct decisions about Content Uniformity or Uniformity of Dosage Units with high probability. The applicability of the proposed methodology is further illustrated using an HPLC-UV assay as well as a Near Infra-Red Spectrophotometric method. [less ▲]

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See detailIntérêt de la microscopie vibrationnelle dans la recherche de nouvelles formulations pharma-ceutiques à haute valeur ajoutée.
Sacre, Pierre-Yves ULg; Marini Djang'Eing'A, Roland ULg; Ziemons, Eric ULg et al

Report (2012)

La grande majorité des nouvelles molécules actives présente une faible biodisponibilité dans des formulations pharmaceutiques simples contenant principalement un ou plusieurs constituants et l’actif ... [more ▼]

La grande majorité des nouvelles molécules actives présente une faible biodisponibilité dans des formulations pharmaceutiques simples contenant principalement un ou plusieurs constituants et l’actif faiblement soluble dans l’eau. Dès lors, il est primordial d’investir dans la recherche de nouvelles formulations « plus sophistiquées » (formulations de demain) favorisant la solubilité de l’actif. Cependant cette recherche est limitée par celle de nouveaux outils analytiques pointus permettant de les caractériser, d’étudier les interactions au sein des formulations pharmaceutiques, de comprendre les mécanismes liès à leur formation et in fine de contrôler et garantir leur conformité. Par ailleurs, la Technologie Analytique des Procédés (PAT) est un concept développé par l’Administration Américaine des Aliments et des Médicaments (FDA) et soutenu par l’Agence Européenne des Médicaments (EMA). Ce concept qui devient de plus en plus incontournable (au niveau des dossiers d’Autorisation de Mise sur le Marché). La rapidité de mesure et le caractère non destructif de la spectroscopie vibrationnelle dont fait partie la microscopie Raman la rendent particulièrement compatibles avec ce concept. De plus, les techniques vibrationnelles de part l’absence de préparation de l’échantillon et de l’utilisation de solvant organique rencontrent également le concept de Chimie Verte et donc s’incrivent parfaitement dans un contexte de développement durable et respectueux de l’environnement. L’objectif du présent projet est d’explorer les potentialités de la microscopie Raman dans l’étude pointue des matrices complexes afin d’en améliorer les connaissances tant au niveau de leur charactérisation, des intéractions analyte-matrice que des mécanismes liés à leur formation. L’obtention de ces informations nécéssiteront la recherche de nouvelles méthodologies, outils et règles de décision dédicacés aux aspects qualitatifs et plus encore aux aspects quantiftatifs où l’accès à de telles données est très marginal. L’ensemble de cette recherche sera réalisée sur un modèle complexe, une formulation à haute valeur ajoutée issue de l’industrie pharmaceutique. [less ▲]

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See detailModèles statistiques Bayésiens et méthodologies pour calculer le Design Space (OPTIMAL-DS)
Marini Djang'Eing'A, Roland ULg; Lebrun, Pierre ULg; Hubert, Philippe ULg

Report (2012)

La compréhension des procédés technologiques et industriels dans les secteurs (bio)pharmaceutiques, biotechnologiques, agroalimentaires et environnementaux doit permettre de se conformer aux lignes de ... [more ▼]

La compréhension des procédés technologiques et industriels dans les secteurs (bio)pharmaceutiques, biotechnologiques, agroalimentaires et environnementaux doit permettre de se conformer aux lignes de conduites initiées par la FDA ou d'autres organismes de contrôles. Notamment, le document ICH Q8 introduit les notions de "Process Analytical Technology", de "Quality by Design" et de "Design Space", ayant attraits à la qualité des procédés industriels, des procédés d'analyse ainsi qu'à la qualité des produits finis. Cependant, si les lignes de conduites pour ces exigences sont expliquées, aucune méthodologie pour les atteindre n'est donnée. Or, un nombre considérable de nouvelles entités chimiques sont synthétisées par les laboratoires pharmaceutiques, biotechnologiques ou agroalimentaires. Les producteurs de matières premières et/ou d’excipients (secteur chimique) ont également besoin de disposer rapidement de méthodes analytiques de contrôle qui leur permettront de s’assurer de la qualité de leurs produits. On comprend aisément la nécessité pour ces secteurs de disposer rapidement de résultats fiables puisque les activités de recherches mais aussi des investissements, souvent importants, sont orientés ou stoppés sur base de données chiffrées, produits par les méthodes analytiques. La production de résultats fiables et la démonstration de cette fiabilité sont donc économiquement fondamentales. Ce projet vise la mise au point de stratégies et de modèles génériques de développement automatisé de nouvelles méthodes analytiques séparatives, en se basant sur la modélisation des temps de rétention, la planification expérimentale, et le concept de Design Space. L’objectif connexe est d’appliquer cette méthodologie à l’optimisation de n’importe quel procédé. Le fait de pouvoir disposer d’une méthodologie de mise au point automatique de méthodes analytiques ou de tous procédés analytiques aura un impact significatif. Cette nouvelle technologie permettra de réduire de façon drastique le temps d’optimisation des méthodes et procédés, permettant une production plus efficiente de produits (pharmaceutique, cosmétique, agro-alimentaire ou biotechnologique) répondant aux spécifications du client. [less ▲]

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See detailAPPLICATION OF AN INNOVATIVE DESIGN SPACE OPTIMIZATION STRATEGY TO THE DEVELOPMENT OF LC METHODS TO COMBAT POTENTIALLY COUNTERFEIT NONSTEROIDAL ANTIINFLAMMATORY DRUGS
Mbinze Kindenge, Jérémie ULg; Lebrun, Pierre ULg; Debrus, Benjamin ULg et al

in Journal of Chromatography. A (2012), 1263

In the context of the battle against counterfeit medicines, an innovative methodology has been used to develop rapid and specific high performance liquid chromatographic methods to detect and determine 18 ... [more ▼]

In the context of the battle against counterfeit medicines, an innovative methodology has been used to develop rapid and specific high performance liquid chromatographic methods to detect and determine 18 non-steroidal anti-inflammatory drugs, 5 pharmaceutical conservatives, paracetamol, chlorzoxazone, caffeine and salicylic acid. These molecules are commonly encountered alone or in combination on the market. Regrettably, a significant proportion of these consumed medicines are counterfeit or substandard, with a strong negative impact in countries of Central Africa. In this context, an innovative design space optimization strategy was successfully applied to the development of LC screening methods allowing the detection of substandard or counterfeit medicines. Using the results of a unique experimental design, the design spaces of 5 potentially relevant HPLC methods have been developed, and transferred to an ultra high performance liquid chromatographic system to evaluate the robustness of the predicted DS while providing rapid methods of analysis. Moreover, one of the methods has been fully validated using the accuracy profile as decision tool, and was then used for the quantitative determination of three active ingredients and one impurity in a common and widely used pharmaceutical formulation. The method was applied to 5 pharmaceuticals sold in the Democratic Republic of Congo. None of these pharmaceuticals was found compliant to the European Medicines Agency specifications [less ▲]

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See detailDevelopment of a generic micellar electrokinetic chromatography method for the separation of 15 antimalarial drugs as a tool to detect medicine counterfeiting
Lamalle, Caroline ULg; Marini Djang'Eing'A, Roland ULg; Debrus, Benjamin ULg et al

in Electrophoresis (2012), 33

Since antimalarial drugs counterfeiting is dramatically present on the African market, the development of simple analytical methods for their quality control is of great importance. This work consists in ... [more ▼]

Since antimalarial drugs counterfeiting is dramatically present on the African market, the development of simple analytical methods for their quality control is of great importance. This work consists in the CE analysis of 15 antimalarials (artesunate, artemether, amodiaquine, chloroquine, piperaquine, primaquine, quinine, cinchonine, mefloquine, halofantrine, sulfadoxine, sulfalen, atovaquone, proguanil, and pyrimethamine). Since all these molecules cannot be ionized at the same pH, MEKC was preferred because it also allows separation of neutral compounds. Preliminary experiments were first carried out to select the most crucial factors affecting the antimalarials separation. Several conditions were tested and four parameters as well as their investigation domain were chosen: pH (5–10), SDS concentration (20–90 mM), ACN proportion (10–40%), and temperature (20–35°C). Then, the experimental design methodology was used and a central composite design was selected. Mathematical modeling of the migration times allowed the prediction of optimal conditions (29°C, pH 6.6, 29 mM SDS, 36% ACN) regarding analyte separation. The prediction at this optimum was verified experimentally and led to the separation of 13 compounds within 8 min. Finally, the method was successfully applied to the quality control of African antimalarial medicines for their qualitative and quantitative content. [less ▲]

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See detailQUALITY ASSESSMENT OF MEDICINES MARKETED IN RWANDA, July-Oct. 2011
Habyalimana, Védaste; Mbinze Kindenge, Jérémie; Kadima Ntokamunda, Justin Léonard et al

Scientific conference (2012, July)

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