Vitamin D-3 is a key micronutrient whose intakes are inadequate for most populations worldwide. Supplementation with medicines or food supplements is commonly prescribed to correct this imbalance and the quality of these products must be ensured. In this context, a generic methodology for the assay of vitamin D-3 in oily formulations is proposed using supercritical fluid chromatography coupled to mass spectrometry (SFC-MS). It is in line with green analytical chemistry principles and combines the use of i) a fast and robust analytical method (4.0 min analysis time) ii) an easy sample preparation compatible with high throughput analysis ("dilute-and-shoot" approach) and iii) a relevant control strategy. Seventeen products from multiple manufacturers and encompassing a large content range were evaluated in this study. They were classified in four groups to streamline their processing considering the use of a matrix-matched calibration procedure. Matrix effect was thoroughly studied and was found to be low (99-106%), stable intra/inter-series and comparable between the different groups and types of matrices. The implemented control strategy was based on a three-level system suitability tests (SST). Level 1 SST: resolution of the critical pair that was above 1.5 for all analysis series. Level 2 SST: evaluation of the adequacy of the calibration for a QC sample in terms of recovery that was between 97% and 104% with a variability between 1% and 2%. Level 3 SST: method trueness that was between 95% and 102%. Sample analysis highlighted differences in types of products and dosage forms. This is the first study to propose a complete strategy for the quality control of vitamin D-3 oily formulations and should prove useful in QC laboratories. (C) 2021 Elsevier B.V. All rights reserved.

Nimesulide, a COX-2 preferential inhibitor with a favorable gastric and cardiovascular safety profile, was responsible for some cases of acute liver failure attributed to the nitrobenzene ring. A series of analogs of nimesulide resulting from isosteric replacement of the nitrobenzene ring by the pyridine nucleus, was synthesized and their ability to inhibit both cyclooxygenases (COXs) isoforms was evaluated in vitro using a human whole blood model. Compounds 19c, 23b and 23c displayed an important inhibitory activity associated to a COX-2/COX-1 selectivity ratio similar to or higher than that of celecoxib. The anti-inflammatory activity and the ability of several compounds to decrease leukocyte infiltration were further evaluated in vivo in a model of a λ carrageenan-induced pleurisy. Plasma assays were performed on blood samples collected from rats and allowed us to identify the 4-position of the phenyl ring as a major metabolism site explaining the occasionally observed lack of correlation between in vitro and in vivo results.

In the following study, we mainly investigate the effects of static magnetic field (SMF) (128 mT, 1 hr/day during 5 consecutive days) on 25-hydroxyvitamin D3 and calcium homeostasis. Wistar male rats, weighing 50-70 g, were randomly divided into four experimental groups: control, SMF-exposed rat, co-exposed rats (the last day and after exposure rats received a single dose of vitamin D per os) and supplemented with vitamin D group (without exposure to SMF). Exposure to SMF induced a decrease of plasmatic 25-hydroxyvitamin D3 level (P < 0.001). While, calcium and phosphorus levels were not affected (P > 0.05). The same treatment failed also to alter body, relative liver and kidney weights. Interestingly, oral supplementation with vitamin D corrected hypovitaminosis D induced by SMF. Likewise, the same treatment failed to alter calcium homeostasis. More studies are needed to evaluate how SMF induces hypovitaminosis D.

This paper focuses on implementing a design space approach and on the critical process parameters (CPPs) to consider when applying the Quality by Design (QbD) concepts outlined in ICH Q8(R2), Q9 and Q10 to analytical method development and optimization for three chiral compounds developed as modulators of small conductance calcium-activated potassium (SK) channels. In this sense, an HPLC method using a polysaccharide-based stationary phase containing a cellulose tris (4-chloro-3-methylphenylcarbamate) chiral selector in polar organic solvent chromatography mode was considered. The effects of trifluoroacetic acid (TFA) and n-hexane concentration in an acetonitrile (MeCN) mobile phase were investigated under a wide range of column temperatures. Good correlations were found between the observed data obtained after using a central composite design and the expected chromatographic behaviours predicted by applying the design of experiments-design space (DoE-DS) methodology. The critical quality attribute represented here by the separation criterion (Scrit) allowed assessing the quality of the enantioseparation. Baseline separation for the compounds of interest in an analysis time of less than 20 min was possible due to the original and powerful tools applied which facilitated an enhanced method comprehension. Finally, the advantage of the DoE-DS approach resides in granting the possibility to concurrently assess robustness and identify the optimal conditions which are compound dependent.

Depuis plusieurs annees, le Laboratoire de Chimie Pharmaceutique de l’Universite de Liege s’interesse a la synthese et l’evaluation pharmacologique de molecules inhibitrices de cyclooxygenases (COX) apparentees au nimesulide, un anti-inflammatoire non steroidien 1,2 . Ces enzymes, connues sous deux isoformes COX-1 et COX-2, sont impliquees dans la synthese des prostanoides dont une surproduction a ete mise en evidence dans diverses conditions pathologiques telles que l’inflammation et le cancer. Le point de depart de ce projet est le remplacement du noyau nitrobenzenique du nimesulide par un cycle pyridinique (fig.1).

Cidofovir (CDV) is an acyclic cytidine monophosphate analog that as a broad antiviral spectrum including herpes viruses, adenoviruses, poxviruses, papillomavirus, and hepadnaviruses. Topical administration of cidofovir has been shown to be effective in the treatment of cutaneous infections of different viruses in animal models [1-2]. CDV is currently undergoing evaluation in clinical trials as a topic agent for treatment of papillomavirus infections [1,3]. An important adverse effect associeted with intravenous cidofovir is renal tubular damage. The main goal of this method was the CDV determination in human plasma after topical treatment so as to study the distribution in human body. Cidofovir is a polar molecule that has three ionizable functions. CDV present a zwitterionic character in aqueous media and therefore, it was an excellent candidate for determination by hydrophilic interaction chromatography (HILIC). This mode is an interesting alternative to reverse-phase liquid chromatography for the analysis of ionizable compounds [4]. The analytical conditions were optimized by means of designs of experiments.The bare silica column selected was a Grace Alltima HP HILIC. The isocratic separation was performed at a temperature of 25°C using a mobile phase consisting in a mixture of acetonitrile – 20 mM ammonium hydrogen carbonate buffer at pH 7 (72/28, v/v). Validation should ensure that the analytical procedure is fit for its purpose. In this application the aim of the developed method is to quantify CDV in plasma. A total error approach was used to demonstrate the fitness of the method using tolerance interval methodology and accuracy profile as decision tool. The tolerance interval used is a “β-expectation tolerance interval” defining an interval in which it is expected that each future result will fall with a defined probability β. It is therefore a predictive tool [5]. The concept of accuracy profile was also used to select the most appropriate regression model for calibration, to determine the lower limit of quantitation (LLOQ) and the range over which the method can be considered as valid. This newly developed method was then fully validated according to FDA requirements [6] by means of a Total Error approach that guaranteed that each future result will fall within acceptance limits of ±30% with a minimum probability β settled at 95% over a concentration range of 100 to 1020 ng/ml. Nonetheless, the routine application of the cidofovir assay in a pre-clinical trial demonstrated that the prediction made during the pre-study validation was consistent. Actually the minimum probability to observe QC samples within the ±30% acceptance limits was successfully of 95%.

1 Department of Pharmacy, Laboratory of Analytical Chemistry, CIRM, University of Liege, avenue de l’Hopital 1, 4000, Liege, Belgium, 2 Faculty of Pharmacy, Laboratory of Analytical Chemistry, University of Medicine and Pharmacy ‘Iuliu Hatieganu’, Pasteur street 4, 400349, Cluj-Napoca, Romania, 3 LACOMEDA, Faculty of Pharmaceutical Sciences, University of Kinshasa, BP 212 Kinshasa XI, Democratic Republic of Congo

Connue depuis des décennies [1,2], la chromatographie liquide d’interactions hydrophiles (HILIC) a pris de plus en plus d’importance au cours de ces dernières années pour l’analyse de composés polaires. Le mode HILIC s’avère être une alternative très intéressante aux modes normale et inverse. En effet, la nature des phases mobiles utilisées s’accorde bien avec la préparation des échantillons biologiques et permet un couplage aisé avec des détecteurs nécessitant une désolvatation tels les spectromètres de masse (MS) et les détecteurs évaporatifs à diffusion de lumière (ELSD). De plus, il existe sur le marché une grande variété de phases stationnaires permettant la séparation et le dosage de molécules polaires très diverses [3,4]. L’acétonitrile est le solvant de choix pour la chromatographie en mode HILIC et ce, malgré son coût et sa disponibilité qui a connu récemment quelques aléas. Dans ce contexte, le méthanol peut aussi être utilisé. Il constitue non seulement une alternative économique intéressante mais offre de plus une sélectivité différente permettant de mener à bien certaines séparations [5]. Au cours de ce travail, les potentialités de ces solvants ont été étudiées pour l’analyse du cidofovir, une molécule polaire, dans le plasma et l’urine. Trois colonnes différentes (ZIC-HILIC, amino et silice vierge) ont été testées et les interactions entre l’analyte et ces phases stationnaires ont été étudiées. L’impact du pH et de la température sur la rétention et la symétrie des pics a également été investigué au moyen de la planification expérimentale. Préalablement à l’analyse chromatographique, les échantillons biologiques ont subi une extraction sur phase solide échangeuse d’ions, étape indispensable à l’amélioration de la sélectivité mais aussi à la pérennité du système chromatographique. Les résultats obtenus lors de l’optimisation de ces différentes étapes seront présentés. Enfin, une méthode de dosage du cidofovir dans le plasma humain a été validée selon l’approche du profil d’exactitude afin de démontrer la fiabilité du mode HILIC en bioanalyse.