Electron spin resonance - thermoluminescence studies on irradiated drugs and excipients

Issu de : 12th International Meeting on Radiation Processing (IMRP-12), AVIGNON, FRANCE, MAR 25-30, 2001International audienceThe methods (ESR, TL, GPC) developed to prove whether or not a foodstuff has been irradiated can be used to get the same proof in case of an irradiation treatment of drugs, excipients and cosmetic products

In vitro and in vivo reversal of resistance to 5-fluorouracil in colorectal cancer cells with a novel stealth double-liposomal formulation

Drug resistance is a major cause of treatment failure in cancer chemotherapy, including that with the extensively prescribed antimetabolite, 5-fluorouracil (5-FU). In this study, we tried to reverse 5-FU resistance by using a double-punch strategy: combining 5-FU with a biochemical modulator to improve its tumoural activation and encapsulating both these agents in one same stealth liposome. Experiments carried out in the highly resistant, canonical SW620 human colorectal model showed a up to 80% sensitisation to 5-FU when these cells were treated with our liposomal formulation. Results with this formulation demonstrated 30% higher tumoural drug uptake, better activation with increased active metabolites including critical-5-fluoro-2-deoxyuridine-5-monophosphate, superior inhibition (98%) of tumour thymidylate synthase, and subsequently, higher induction of both early and late apoptosis. Drug monitoring showed that higher and sustained exposure was achieved in rats treated with liposomal formulation. When examined in a xenograft animal model, our dual-agent liposomal formulation caused a 74% reduction in tumour size with a mean doubling in survival time, whereas standard 5-FU failed to exhibit significant antiproliferative activity as well as to increase the lifespan of tumour-bearing mice. Taken collectively, our data suggest that resistance to 5-FU can be overcome through a better control of its intratumoural activation and the use of an encapsulated formulation

The evaluation of cosmetic and pharmaceutical emulsions aging process using classical techniques and a new method: FTIR

International audienceThe purpose of this paper is to show how the utilization of Fourier Transform Infrared (FTIR) spectroscopy can be interesting in stability studying of cosmetic or pharmaceutical "oil in water" (O/W) emulsions. In this study temperature storage tests were performed to accelerate the aging process and evaluate the stability of five emulsions. Emulsions were analyzed by FTIR and classical methods (conductivity, viscosity, pH, texture analysis) in order to determine a method that would enable predicting the emulsion's stability. During the aging process, modifications of chemical functions are measured by FTIR (using spectrometric indices), such modifications included: a decrease of unsaturation index, an increase of carbonyl index and a broadening of the carbonyl band. This band was deconvoluted to evaluate the contribution of different species in the broadening phenomenon, which seems to be caused by the appearance of free fatty acids. Conductimetry seems to be the most sensitive technique to assess physical modifications during emulsion's aging. Concerning the most unstable emulsions, a progressive increasing of conductivity was observed several months before the emulsion destabilizes. Consequently, FTIR and conductimetry are two complementary techniques. Conductimetry is a useful technique to predict emulsion destabilization while FTIR allows the measurement of chemical modifications and helps to understand the chemical mechanisms which occur during the oxidation

Quantification de processus radiculaires induits dans diverses poudres

National audienc

Apport de I'IRTF et de la rhéologie à l'étude de la stabilité d'émulsions cosmétiques H/E

International audienc

An innovative floating gastro retentive dosage system: Formulation and in vitro evaluation

International audienceOver the years, different formulation technologies intended for gastro retentive dosage delivery were investigated and patented. The aim of this study was to develop an innovative floating gastro retentive dosage form (GRDF). The developed technology induces a low-density dosage form containing high active pharmaceutical ingredient (API) concentration by using a hydrophobic dusty powder excipient under specific conditions. The new dosage form was obtained by state of the art wet granulation manufacturing process. An experimental design using a discrete variable and four mixture variables was conducted in order to optimize API concentration and buoyancy of the new dosage form. An apparatus was developed to measure the apparent density of floating tablet. The GRDF was characterized for apparent density, buoyancy, porosity and dissolution using in vitro experimentations

Electron paramagnetic resonance of radicals induced in drugs and excipients by radiation or mechanical treatments

7th International Workshop on Electron Magnetic Resonance of Disorded Systems, SOFIA BOYANA, BULGARIA, JUN 09-18, 2001International audienceRadiation as well as mechanical treatments induced in drugs and excipients radicals, which can be studied by electron paramagnetic resonance. A special attention is pointed about the use of electron paramagnetic resonance (EPR) to bring the proof whether or not a drug has been irradiated or not. We also discuss of other methods (thermoluminescence (TL), gas phase chromatography (GPC)) which can be used to bring the same proof in case of irradiated drugs, excipients and cosmetic products. (C) 2002 Elsevier Science B.V. All rights reserved