Chemical imaging of small molecules from simple to complex matrices: Quantitative approches based on Surface Enhanced Raman scattering

Conference (2013, July)

Surface Enhanced Raman scattering (SERS) allows to dramatically exalt the Raman diffusion of molecules absorbed or very closed to rough metallic surfaces while keeping their structural information. SERS ... [more ▼]

Surface Enhanced Raman scattering (SERS) allows to dramatically exalt the Raman diffusion of molecules absorbed or very closed to rough metallic surfaces while keeping their structural information. SERS chemical imaging, presenting a high specificity and sensibility, allows acquiring a visual representation of samples combining spectral and spatial measurements. This technique could become a powerful tool in pharmaceutical and biological analysis enabling to identify and quantify molecules thanks to chemometric evaluation while looking at their distribution or their interactions. In this context, SERS chemical imaging is investigated in detection or quantitative determination of molecules in pharmaceutical and biological matrices. The feasibility of making quantitative measurements using SERS is evaluated on small target molecules models such as 4-aminophenol and lactate. Firstly, a SERS method to quantify 4-aminophenol which is the primary impurity of acetaminophen coming from its degradation during the storage or from its synthesis was developed on a real pharmaceutical formulation. The standard addition method was selected as calibration method in order to take into account the matrix effect coming from the different components of the latter. Despite the well-known stability and repeatability problems of SERS, the method was thoroughly validated by means of accuracy profiles as decision tool. Moreover, this validation methodology allowed to define a first estimation of the real analytical performance of the technique. Secondly, the detection of lactate, which is a critical metabolite implicated in several metabolic disorders, was successfully tested in the physiological concentration in a simple matrix. Preliminary results for the determination of this metabolic biomarker were also very promising allowing to consider more complex matrices. Based on these results, SERS chemical imaging was implemented to detect 4-aminophenol in a pharmaceutical tablet formerly pulverised by a SERS substrate. Through this imaging technique, it was not only possible to detect the presence of the impurity at the limit of specification of 0.1% (w/w) but it was also possible to differentiate tablets comprising different concentrations of the latter. These promising results represent the first step towards quantitative measurements using SERS chemical imaging. [less ▲]

Nanovecteurs polymériques et lipidiques pour le traitement du cancer: développements en cours et perspectives

Scientific conference (2013)

Evaluation of a new biocompatible poly(N-(morpholino ethyl methacrylate)-based copolymer for the delivery of ruthenium oligonucleotides, targeting HPV16 E6 oncogene

in Journal of Biomedical Nanotechnology (2013), 9

This study investigates the use of a new biocompatible block copolymer poly(2-(dimethylamino)ethyl methacrylate-N-(morpholino)ethyl methacrylate (PDMAEMA-b-PMEMA) for the delivery of a particular ... [more ▼]

This study investigates the use of a new biocompatible block copolymer poly(2-(dimethylamino)ethyl methacrylate-N-(morpholino)ethyl methacrylate (PDMAEMA-b-PMEMA) for the delivery of a particular antisense oligonucleotide targeting E6 gene from human papilloma virus. This antisense oligonucleotide was derivatized with a polyazaaromatic RuII complex which, under visible illumination, is able to produce an irreversible crosslink with the complementary targeted sequence. The purpose of this study is to determine whether by the use of a suitable transfection agent, it is possible to increase the efficiency of the antisense oligonucleotide targeting E6 gene, named Ru-P-4. In a recent study, we showed that Oligofectamine® transfected Ru-P-4 antisense oligonucleotide failed to inhibit efficiently the growth of cervical cancer cell line SiHa, contrarily to the Ru-P-6 antisense oligonucleotide, another sequence also targeting the E6 gene. The ability of PDMAEMA-b-PMEMA to form polyplexes with optimal physicochemical characteristics was investigated first. Then the ability of the PDMAEMA-b-PMEMA/Ru-P-4 antisense oligonucleotide polyplexes to transfect two keratinocyte cell lines (SiHa and HaCat) and the capacity of polyplexes to inhibit HPV16 + cervical cancer cell growth was evaluated. PDMAEMA-b-PMEMA base polyplexes at the optimal molar ratio of polymer nitrogen atoms to DNA phosphates (N/P), were able to deliver Ru-P-4 antisense oligonucleotide and to induce a higher growth inhibition in human cervical cancer SiHa cells, compared to other formulations based on Oligofectamine®. [less ▲]

UNDERSTANDING THE INTERACTIONS BETWEEN ARTEMISININ AND CYCLODEXTRINS: SPECTROSCOPIC STUDIES AND MOLECULAR MODELING

in Journal of Inclusion Phenomena and Molecular Recognition in Chemistry (2012), 74(1), 305-315

NUCLEAR DELIVERY OF A THERAPEUTIC PEPTIDE BY LONG CIRCULATING pH-SENSITIVE LIPOSOMES: BENEFITS OVER CLASSICAL VESICLES

Poster (2011, December 06)

Liposome surface charge influence on skin penetration behaviour

in International Journal of Pharmaceutics (2011), 411(1-2), 223-231

Parameters influencing the skin penetration effectiveness of liposomes

Conference (2011, May 12)

Peptide-loaded pH-sensitive Liposomes: effective penetration of Print3G in the nucleus of cancer cells

Conference (2011, March 25)

Liposomes and parameters affecting their skin penetration behaviour

in Journal of Drug Delivery Science and Technology [=JDDST] (2011), 21

Powdered lipid nano and microparticles : production and applications

in Recent Patents on Drug Delivery & Formulation (2011), 5(3), 188-200

This review details articles and recent patents in an emerging topic called powdered form of nano- and microparticles. Solid lipid particles were developed in the early 1990s and since, they have been ... [more ▼]

This review details articles and recent patents in an emerging topic called powdered form of nano- and microparticles. Solid lipid particles were developed in the early 1990s and since, they have been considered as promising drug delivery systems, especially in providing a sustained release profile of the encapsulated drug. This kind of drug delivery system has several advantages, due to its physiological composition. It is generally well tolerated by the human body and are relatively stable during storage in comparison with other carriers like liposomes. The description of these powdered lipid particles, their different production processes and their applications are the focus of the article. [less ▲]