Permeability coefficients and vapour pressure determination for fragrance materials.

OBJECTIVE: This study aims to correlate new experimental data relevant to the description of the combined evaporation/permeation process of a perfume applied onto the skin. METHODS: The vapour pressure data were measured by thermogravimetric analysis (TG-DTA). The Antoine constants and the Clarke and Glew parameters were determined for the same set of fragrance molecules to describe its low vapour pressures at new temperature ranges. The permeability coefficient of a set of 14 fragrance molecules in ethanolic solution was determined by Franz diffusion cell experiments, using porcine skin. The samples were analysed by gas chromatography with a flame ionization detector (GC/FID) and high-performance liquid chromatography with UV visible detector (HPLC/UV). A QSAR model was proposed to correlate the experimental data. RESULTS: The Antoine constants were determined and presented low standard deviations. The Clarke and Glew physically significant parameters were obtained along with its statistical analysis. The fitting is good since the magnitude order is in accordance with the literature, associated with the low correlation between the estimated parameters and low standard deviations. The presented correlation, based on a mixture using only ethanol as solvent, showed better results than previous QSAR models with a standard relative deviation ( σ r ) of 0.190, a standard error (SE) of 0.397 and a determination coefficient (R2 ) of 0.7786. CONCLUSION: The dataset is still small compared to larger and more general QSAR models; however, it is much more specific as to the type of solvent and class of materials studied. This work represents an advance for the modelling of the perfume diffusion process since it specifies important properties that until then had been treated in a more general way.

OBJECTIF: Cette étude vise à corréler de nouvelles données expérimentales pertinentes à la description du processus combiné d'évaporation/perméation d'un parfum appliqué sur la peau. MÉTHODES: Les données de pression de vapeur ont été mesurées par analyse thermogravimétrique (TG-DTA). Les constantes d'Antoine et les paramètres de Clarke & Glew ont été déterminés pour le même ensemble de molécules de parfum afin de décrire ses faibles pressions de vapeur à de nouvelles plages de température. Le coefficient de perméabilité d'un ensemble de 14 molécules de parfum en solution éthanolique a été déterminé par des expériences de cellules de diffusion de Franz, en utilisant de la peau de porc. Les échantillons ont été analysés par chromatographie en phase gazeuse avec un détecteur à ionisation de flamme (GC / FID) et chromatographie liquide haute performance avec détecteur UV visible (HPLC / UV). Un modèle QSAR a été proposé pour corréler les données expérimentales. RÉSULTATS: Les constantes d'Antoine ont été déterminées et ont présenté de faibles écarts types. Les paramètres physiquement significatifs de Clarke & Glew ont été obtenus avec son analyse statistique. L'ajustement est bon car l'ordre de grandeur est conforme à la littérature, associé à la faible corrélation entre les paramètres estimés et les faibles écarts types. La corrélation présentée, basée sur un mélange utilisant uniquement de l'éthanol comme solvant, a montré de meilleurs résultats que les modèles QSAR précédents avec un écart relatif standard (σr) de 0,190, une erreur standard (SE) de 0,397 et un coefficient de détermination (R2) de 0,7786. CONCLUSION: L'ensemble de données est encore petit par rapport aux modèles QSAR plus grands et plus généraux ; cependant, il est beaucoup plus spécifique quant au type de solvant et à la classe de matériaux étudiés. Ce travail représente une avancée pour la modélisation du processus de diffusion des parfums car il précise des propriétés importantes jusque-là traitées de manière plus générale.

A valepotriate-enriched fraction from Valeriana glechomifolia Meyer inhibits leukocytes migration and nociception in formalin test in rodents

Abstract Previous pre-clinical studies demonstrated that a valepotriates enriched fraction from Valeriana glechomifolia F.G. Mey., Caprifoliaceae, was effective against lipopolysaccharide from Escherichia coli (LPS)-induced sickness behavior as well as significantly decreased the cortical expression of pro inflammatory cytokines interleukin-1β and tumor necrosis factor-α. Other studies revealed anti-inflammatory properties of V. wallichii and V. amurensis. These findings open up new perspectives for Valeriana genus pharmacology, once it has been commonly associated to sedative and anxiolytic properties. The aim of this study was to investigate the antichemotactic, antinociptive and anti-inflammatory activities of a valepotriate-enriched fraction obtained from aerial and subterranean parts of V. glechomifolia submitted to supercritical CO2 extraction. The biological activities were assessed by means of formalin test in CF1 mice and Wistar rat's leukocytes migration assay (modified Boyden chamber method). Valepotriate-enriched fraction (1, 10 and 30 mg/kg, p.o.) inhibited the nociceptive behavior in the late phase of the formalin test in a dose dependent manner. The effect of the valepotriate-enriched fraction highest dose was comparable with that of diclofenac 50 mg/kg (p.o.). Valepotriate-enriched fraction (0.1-1 µg/ml) inhibited the leukocyte migration induced by lipopolysaccharide from Escherichia coli in a concentration dependent manner. This antichemotatic effect was comparable with that of indomethacin (0.1-1 µg/ml) and better than diclofenac (1 µg/ml) effect. This study demonstrated for the first time that a valepotriate-enriched fraction obtained from V. glechomifolia display a peripheral anti-inflammatory like activity.

Supercritical extraction of phloroglucinol and benzophenone derivatives from Hypericum carinatum: quantification and mathematical modeling.

The aerial parts of Hypericum carinatum (Guttiferae) were extracted with supercritical carbon dioxide under constant temperature (40, 50 or 60°C) and gradual pressure increase (90, 120, 150 and 200 bar) aiming at the recovery of enriched fractions containing uliginosin B, cariphenone A and cariphenone B, compounds of pharmaceutical interest. The yields of these substances were determined by high-performance liquid chromatography and compared with those obtained with n-hexane maceration. The supercritical-fluid extraction showed higher selectivity than the conventional solvent extraction method. After defining 40°C and 90 bar as the best conditions to obtain the target compounds, a mathematical model was used for the extraction process and a good correlation was achieved with the experimental data.