Rapid and Simple Flow Injection Analysis-Tandem Mass Spectrometric (FIA-MS/MS) Method for the Quantification of Melphalan in Lipid-Based Drug Delivery System

Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Foundation for Innovation (CFI)Peer ReviewedThe use of the anticancer drug melphalan is limited due to its poor water solubility. To address such limitation, it is incorporated within a novel delivery system using β-cyclodextrin-gemini surfactants (18:1βCDg). Herein, two fast and simple FIA-MS/MS methods are developed for the quantification of melphalan (Mel) within the drug delivery system so that the solubilization efficiency of the system can be assessed. FIA-MS/MS methods are developed using a triple quadrupole-linear ion trap mass spectrometer, equipped with electrospray ionization (ESI) in the positive ion mode. A deuterated form of melphalan (melphalan-d8) was used as an internal standard (IS). The methods were validated according to the FDA guidance. A linearity in the range of 2–100 ng/mL and accuracy and precision below 15% were observed for all standard points and quality control samples. The intra- and inter-day variations, freeze-thaw stability were within the acceptable range according to the criteria set by regulatory guidelines. On the other hand, other stability measures, such as room temperature stability and long term stability did not meet the required guidelines in some cases, indicating the need for quick sample analysis upon preparation. Such a fact could have been overlooked if full method validation was not performed. The developed methods were applied to determine the encapsulation/solubilisation of [18:1βCDg\Mel] delivery system. 18:1βCDg enhances the aqueous solubility of melphalan without the need for co-solvent. The highest melphalan solubility was observed at the 18:1βCDg\Mel complex molar ratio of 2:1. This study demonstrated that a fast analysis for the purpose of quantifying a chemically unstable drug, such as melphalan is feasible and important for the development of commercial dosage forms

L’autorégulation de l’apprentissage par la lecture d’adolescents en milieu défavorisé

Cette étude a pour but de présenter les portraits d’autorégulation, lors de l’apprentissage par la lecture, de 20 545 élèves du secondaire (12 à 17 ans) fréquentant 59 écoles francophones de milieux défavorisés du Québec. Elle repose sur le questionnaire d’évaluation Lire pour apprendre (Cartier et Butler, 2003). Les résultats montrent que les élèves voient une certaine complexité à la situation, par leur interprétation, leurs objectifs et les critères de performance. Le volet apprentissage de la situation est moins ciblé. Par ailleurs, les élèves présentent des portraits d’autorégulation lacunaires. Des différences d’autorégulation entre les élèves du début et de la fin du secondaire ont été observées.This study presents a portrait of the self-regulated learning-by-reading strategies of 20,545 secondary level students (aged 12 to 17) from 59 Francophone schools in low socio-economic areas in Quebec. The authors applied an evaluation questionnaire, “Lire pour apprendre” (Cartier et Butler, 2003). Results show that students understand the complexity of a situation based on their interpretation, their objectives and their performance criteria. The learning aspect in the situation is less targeted. However, students present self-regulated learning strategies that are inadequate. Differences in self-regulation by students at the beginning and at the end of the secondary level were found.Este estudio tiene por objetivo presentar los perfiles de autorregulación durante el aprendizaje por la lectura de 20 545 alumnos de la secundaria (de 12 a 17 años de edad) provenientes de 59 escuelas francófonas de medios desfavorecidos de la provincia de Quebec. Se fundamenta en el cuestionario de evaluación Lire pour apprendre (Cartier y Butler, 2003). Los resultados muestran que los alumnos encuentran una cierta complejidad a la situación por su interpretación, sus objetivos y los criterios de desempeño. La parte « aprendizaje » de la situación se encuentra menos señalada. Por otro lado, los alumnos presentan perfiles de autorregulación con lagunas. Se observaron diferencias de autorregulación entre los alumnos del principio y del final de la secundaria

Development and validation of fast and simple flow injection analysis-tandem mass spectrometry (FIA-MS/MS) for the determination of metformin in dog serum

Canada Foundation for Innovation; University of SaskatchewanA simple, fast and sensitive quantification method for the drug metformin in dog serum was developed using flow injection analysis (FIA)- tandem mass spectrometry (MS/MS). The method was fully validated according to industry standards. It is the first time that FIA-MS/MS for metformin was developed surpassing all existing methods in terms of time of analysis. The quantification method was dependent on the formation of [M+H]+ using electrospray ionization (ESI) and employing multiple reaction monitoring (MRM) using quadrupole- linear ion trap (4000 QTRAP®) instrument. A deuterated internal standard (IS) of metformin bearing six deuterium atoms was used to compensate for matrix effects and for variation in ion current within the ESI source. The ion transitions that were monitored were m/z 130.1 -> m/z 71.0 and m/z 130.1-> m/z 60.1 for metformin and m/z 136.0 -> m/z 77.0 for the internal standard. A linear response (r = 0.9966) was established for a range of concentrations of 5- 2340 ng/ml. The inter- and intra-day variations were within the acceptable criteria for all quality control samples. The method was successfully applied for measurement of serum metformin concentration in dogs after intravenous injection

HILIC-LC-MS/MS quantitative method for the cellular analysis of varying structures of gemini surfactants designed as nanomaterial drug carriers

Canada Foundation for Innovation; Natural Sciences and Engineering Research Council of CanadaDiquaternary gemini surfactants have successfully been used to form lipid-based nanoparticles that are able to compact, protect, and deliver genetic materials into cells. However, what happens to the gemini surfactants after they have released their therapeutic cargo is unknown. Such knowledge is critical to assess the quality, safety, and efficacy of gemini surfactant nanoparticles. We have developed a simple and rapid liquid chromatography electrospray ionization-tandem mass spectrometry (LC-ESI–MS/MS) method for the quantitative determination of various structures of gemini surfactants in cells. Hydrophilic interaction liquid chromatography (HILIC) was employed allowing for a short simple isocratic run of only 4 minutes. The lower limit of detection (LLOD) was 3 ng/mL. The method was valid to 18 structures of gemini surfactants belonging to two different structural families. A full method validation was performed for two lead compounds according to USFDA guidelines. The HILIC-MS/MS was compatible with the physicochemical properties of gemini surfactants that bear a permanent positive charge with both hydrophilic and hydrophobic elements within their molecular structure. In addition, an effective liquid-liquid extraction method (98% recovery) was employed surpassing previously used extraction methods. The analysis of nanoparticle-treated cells showed an initial rise in the analyte intracellular concentration followed by a maximum and a somewhat more gradual decrease of the intracellular concentration. The observed intracellular depletion of the gemini surfactants may be attributable to the bio­transformation into metabolites and exocytosis from the host cells. Obtained cellular data showed a pattern that grants additional investigations , evaluating metabolite formation and assessing the subcellular distribution of tested compounds

Concert recording 2022-10-02

[Track 1]. Grand duo concertant, op. 48. I. Allegro con fuoco ; II. Andante con moto ; III. Ronda, Allegro / Carl Maria von Weber -- [Track 2]. Impromptu: duo for clarinet and marimba / William A.R. May -- [Track 3]. Sonata in E-flat major, op. 120, no. 2. I. Allegro amabile ; II. Allegro appassionato ; III. Andante con moto, Allegro / Johannes Brahms -- [Track 4]. Adoration / Florence Price ; arr. Larkin Sanders -- [Track 5]. Blue skies / Irving Berlin ; arr. R. Percival

Concert recording 2022-10-02

[Track 1]. Grand duo concertant, op. 48. I. Allegro con fuoco ; II. Andante con moto ; III. Ronda, Allegro / Carl Maria von Weber -- [Track 2]. Impromptu: duo for clarinet and marimba / William A.R. May -- [Track 3]. Sonata in E-flat major, op. 120, no. 2. I. Allegro amabile ; II. Allegro appassionato ; III. Andante con moto, Allegro / Johannes Brahms -- [Track 4]. Adoration / Florence Price ; arr. Larkin Sanders -- [Track 5]. Blue skies / Irving Berlin ; arr. R. Percival

Evaluation of cellular uptake and intracellular trafficking as determining factors of gene expression for amino acid-substituted gemini surfactant-based DNA nanoparticles

<p>Abstract</p> <p>Background</p> <p>Gene transfer using non-viral vectors offers a non-immunogenic and safe method of gene delivery. Cellular uptake and intracellular trafficking of the nanoparticles can impact on the transfection efficiency of these vectors. Therefore, understanding the physicochemical properties that may influence the cellular uptake and the intracellular trafficking can aid the design of more efficient non-viral gene delivery systems. Recently, we developed novel amino acid-substituted gemini surfactants that showed higher transfection efficiency than their parent compound. In this study, we evaluated the mechanism of cellular uptake of the plasmid/gemini surfactant/helper lipid nanoparticles and their effect on the transfection efficiency.</p> <p>Results</p> <p>Nanoparticles were incubated with Sf 1 Ep cells in the presence of different endocytic inhibitors and gene expression (interferon-γ) was measured using ELISA. Clathrin-mediated and caveolae-mediated uptake were found to be equally contributing to cellular internalization of both P/12-7NH-12/L (parent gemini surfactant) and P/12-7NGK-12/L (amino acid-substituted gemini surfactant) nanoparticles. The plasmid and the helper lipid were fluorescently tagged to track the nanoparticles inside the cells, using confocal laser scanning microscopy. Transmission electron microscopy images showed that the P/12-7NGK-12/L particles were cylindrical while the P/12-7NH-12/L particles were spherical which may influence the cellular uptake behaviour of these particles. Dye exclusion assay and pH-titration of the nanoparticles suggested that high buffering capacity, pH-dependent increase in particle size and balanced DNA binding properties may be contributing to a more efficient endosomal escape of P/12-7NGK-12/L compared to the P/12-7NH-12/L nanoparticles, leading to higher gene expression.</p> <p>Conclusion</p> <p>Amino-acid substitution in the spacer of gemini surfactant did not alter the cellular uptake pathway, showing similar pattern to the unsubstituted parent gemini surfactant. Glycyl-lysine substitution in the gemini spacer improved buffering capacity and imparted a pH-dependent increase of particle size. This property conferred to the P/12-7NGK-12/L nanoparticles the ability to escape efficiently from clathrin-mediated endosomes. Balanced binding properties (protection and release) of the 12-7NGK-12 in the presence of polyanions could contribute to the facile release of the nanoparticles internalized via caveolae-mediated uptake. A more efficient endosomal escape of the P/12-7NGK-12/L nanoparticles lead to higher gene expression compared to the parent gemini surfactant.</p

A linked data representation for summary statistics and grouping criteria

Summary statistics are fundamental to data science, and are the buidling blocks of statistical reasoning. Most of the data and statistics made available on government web sites are aggregate, however, until now, we have not had a suitable linked data representation available. We propose a way to express summary statistics across aggregate groups as linked data using Web Ontology Language (OWL) Class based sets, where members of the set contribute to the overall aggregate value. Additionally, many clinical studies in the biomedical field rely on demographic summaries of their study cohorts and the patients assigned to each arm. While most data query languages, including SPARQL, allow for computation of summary statistics, they do not provide a way to integrate those values back into the RDF graphs they were computed from. We represent this knowledge, that would otherwise be lost, through the use of OWL 2 punning semantics, the expression of aggregate grouping criteria as OWL classes with variables, and constructs from the Semanticscience Integrated Ontology (SIO), and the World Wide Web Consortium’s provenance ontology, PROV-O, providing interoperable representations that are well supported across the web of Linked Data. We evaluate these semantics using a Resource Description Framework (RDF) representation of patient case information from the Genomic Data Commons, a data portal from the National Cancer Institute