Cοmprendre le cοmpοrtement de mοlécules parfumantes au sein d'émulsiοns cοsmétiques pοur cοntrôler les fοrmules de demain

Fragrance is an essential ingredient in cosmetics, influencing the purchase decision and the perception of products’ performance and sensory properties. It is generally a mix of dozens of individual fragrance molecules (FM), which are distributed between the different phases of the emulsions to which the fragrance is added, potentially altering the stability as well as the physicochemical and applicative properties of the systems. Despite the interest in studying the behaviour of FM in emulsions to optimise cosmetic formulations, there is currently little research on emulsions stabilized by liquid crystalline phases, although their use is very common in skincare products.This thesis therefore aims to remedy this lack of information. The objective is to study fragrance-matrix interactions, in order to understand the effect of FM on the properties of cosmetic emulsions. To this end, solutions of FM in water and oil phases were studied in order to understand their behaviour in emulsion. Then, fifteen oil-in-water (O/W) lamellar emulsions of varying composition (percentage and nature of FM and oil phases introduced) were formulated, according to a controlled protocol. The microstructure, as well as the rheological, sensory and textural profiles of emulsions, were then characterised to study the effect of FM on these properties.The results of this work highlighted the importance of the phase behaviour of FM on their interactions with the other ingredients of the matrix, which govern their location in the emulsified system and their impact on the physicochemical properties. FM had a significant impact on the microstructure, viscoelastic properties, texture, consistency and spreading difficulty of emulsions on the skin.Le parfum est un ingrédient essentiel en cosmétique, qui influence la décision d’achat des produits et la perception de leur performance et de leurs propriétés sensorielles. Il est généralement composé de plusieurs dizaines de molécules parfumantes (MP), qui se répartissent entre les différentes phases des émulsions dans lesquelles le parfum est ajouté, pouvant entraîner une altération de la stabilité ainsi que des propriétés physicochimiques et applicatives des systèmes. En dépit de l’intérêt que présente l’étude du comportement des MP en émulsion en vue de l’optimisation des formulations cosmétiques, il existe peu de recherches appliquées à des émulsions stabilisées par des phases liquides cristallines, qui sont pourtant très répandues dans les produits de soin de la peau.Ce projet de thèse vise donc à pallier ce manque d’information. L’objectif est d’étudier les interactions parfum – matrice, afin d’appréhender l’effet des MP sur les propriétés d’émulsions cosmétiques lamellaires. Pour cela, des solutions de MP dans l’eau et dans les phases grasses ont préalablement été étudiées afin d’appréhender leur comportement en émulsion. Puis, quinze émulsions lamellaires huile-dans-eau (H/E) de composition variable (pourcentage et nature des MP et des phases grasses introduites) ont été formulées, selon un protocole maîtrisé. La microstructure, ainsi que les profils rhéologique, sensoriel et de texture des émulsions ont ensuite été caractérisés dans le but d’étudier l’effet des MP sur ces propriétés.Les résultats de ces travaux ont mis en évidence l’importance du comportement de phase des MP sur leurs interactions avec les autres ingrédients de la matrice, qui gouvernent leur localisation dans le système émulsionné et leur impact sur les propriétés physico-chimiques. Les MP ont eu un impact significatif sur la microstructure, les propriétés viscoélastiques, la texture, la consistance et la difficulté d’étalement des émulsions sur la peau

Understanding the behaviour of fragrance molecules in cosmetic emulsions to control tomorrow’s formulas

Le parfum est un ingrédient essentiel en cosmétique, qui influence la décision d’achat des produits et la perception de leur performance et de leurs propriétés sensorielles. Il est généralement composé de plusieurs dizaines de molécules parfumantes (MP), qui se répartissent entre les différentes phases des émulsions dans lesquelles le parfum est ajouté, pouvant entraîner une altération de la stabilité ainsi que des propriétés physicochimiques et applicatives des systèmes. En dépit de l’intérêt que présente l’étude du comportement des MP en émulsion en vue de l’optimisation des formulations cosmétiques, il existe peu de recherches appliquées à des émulsions stabilisées par des phases liquides cristallines, qui sont pourtant très répandues dans les produits de soin de la peau.Ce projet de thèse vise donc à pallier ce manque d’information. L’objectif est d’étudier les interactions parfum – matrice, afin d’appréhender l’effet des MP sur les propriétés d’émulsions cosmétiques lamellaires. Pour cela, des solutions de MP dans l’eau et dans les phases grasses ont préalablement été étudiées afin d’appréhender leur comportement en émulsion. Puis, quinze émulsions lamellaires huile-dans-eau (H/E) de composition variable (pourcentage et nature des MP et des phases grasses introduites) ont été formulées, selon un protocole maîtrisé. La microstructure, ainsi que les profils rhéologique, sensoriel et de texture des émulsions ont ensuite été caractérisés dans le but d’étudier l’effet des MP sur ces propriétés.Les résultats de ces travaux ont mis en évidence l’importance du comportement de phase des MP sur leurs interactions avec les autres ingrédients de la matrice, qui gouvernent leur localisation dans le système émulsionné et leur impact sur les propriétés physico-chimiques. Les MP ont eu un impact significatif sur la microstructure, les propriétés viscoélastiques, la texture, la consistance et la difficulté d’étalement des émulsions sur la peau.Fragrance is an essential ingredient in cosmetics, influencing the purchase decision and the perception of products’ performance and sensory properties. It is generally a mix of dozens of individual fragrance molecules (FM), which are distributed between the different phases of the emulsions to which the fragrance is added, potentially altering the stability as well as the physicochemical and applicative properties of the systems. Despite the interest in studying the behaviour of FM in emulsions to optimise cosmetic formulations, there is currently little research on emulsions stabilized by liquid crystalline phases, although their use is very common in skincare products.This thesis therefore aims to remedy this lack of information. The objective is to study fragrance-matrix interactions, in order to understand the effect of FM on the properties of cosmetic emulsions. To this end, solutions of FM in water and oil phases were studied in order to understand their behaviour in emulsion. Then, fifteen oil-in-water (O/W) lamellar emulsions of varying composition (percentage and nature of FM and oil phases introduced) were formulated, according to a controlled protocol. The microstructure, as well as the rheological, sensory and textural profiles of emulsions, were then characterised to study the effect of FM on these properties.The results of this work highlighted the importance of the phase behaviour of FM on their interactions with the other ingredients of the matrix, which govern their location in the emulsified system and their impact on the physicochemical properties. FM had a significant impact on the microstructure, viscoelastic properties, texture, consistency and spreading difficulty of emulsions on the skin

Cοmprendre le cοmpοrtement de mοlécules parfumantes au sein d'émulsiοns cοsmétiques pοur cοntrôler les fοrmules de demain

Fragrance is an essential ingredient in cosmetics, influencing the purchase decision and the perception of products’ performance and sensory properties. It is generally a mix of dozens of individual fragrance molecules (FM), which are distributed between the different phases of the emulsions to which the fragrance is added, potentially altering the stability as well as the physicochemical and applicative properties of the systems. Despite the interest in studying the behaviour of FM in emulsions to optimise cosmetic formulations, there is currently little research on emulsions stabilized by liquid crystalline phases, although their use is very common in skincare products.This thesis therefore aims to remedy this lack of information. The objective is to study fragrance-matrix interactions, in order to understand the effect of FM on the properties of cosmetic emulsions. To this end, solutions of FM in water and oil phases were studied in order to understand their behaviour in emulsion. Then, fifteen oil-in-water (O/W) lamellar emulsions of varying composition (percentage and nature of FM and oil phases introduced) were formulated, according to a controlled protocol. The microstructure, as well as the rheological, sensory and textural profiles of emulsions, were then characterised to study the effect of FM on these properties.The results of this work highlighted the importance of the phase behaviour of FM on their interactions with the other ingredients of the matrix, which govern their location in the emulsified system and their impact on the physicochemical properties. FM had a significant impact on the microstructure, viscoelastic properties, texture, consistency and spreading difficulty of emulsions on the skin.Le parfum est un ingrédient essentiel en cosmétique, qui influence la décision d’achat des produits et la perception de leur performance et de leurs propriétés sensorielles. Il est généralement composé de plusieurs dizaines de molécules parfumantes (MP), qui se répartissent entre les différentes phases des émulsions dans lesquelles le parfum est ajouté, pouvant entraîner une altération de la stabilité ainsi que des propriétés physicochimiques et applicatives des systèmes. En dépit de l’intérêt que présente l’étude du comportement des MP en émulsion en vue de l’optimisation des formulations cosmétiques, il existe peu de recherches appliquées à des émulsions stabilisées par des phases liquides cristallines, qui sont pourtant très répandues dans les produits de soin de la peau.Ce projet de thèse vise donc à pallier ce manque d’information. L’objectif est d’étudier les interactions parfum – matrice, afin d’appréhender l’effet des MP sur les propriétés d’émulsions cosmétiques lamellaires. Pour cela, des solutions de MP dans l’eau et dans les phases grasses ont préalablement été étudiées afin d’appréhender leur comportement en émulsion. Puis, quinze émulsions lamellaires huile-dans-eau (H/E) de composition variable (pourcentage et nature des MP et des phases grasses introduites) ont été formulées, selon un protocole maîtrisé. La microstructure, ainsi que les profils rhéologique, sensoriel et de texture des émulsions ont ensuite été caractérisés dans le but d’étudier l’effet des MP sur ces propriétés.Les résultats de ces travaux ont mis en évidence l’importance du comportement de phase des MP sur leurs interactions avec les autres ingrédients de la matrice, qui gouvernent leur localisation dans le système émulsionné et leur impact sur les propriétés physico-chimiques. Les MP ont eu un impact significatif sur la microstructure, les propriétés viscoélastiques, la texture, la consistance et la difficulté d’étalement des émulsions sur la peau

Fragrance in dermocosmetic emulsions: From microstructure to skin application

Abstract Fragrance is added to almost all dermocosmetic emulsions, as it has been found to be a key driver in consumer choice and contributes to the perception of product performance. Fragrance is a complex mixture of odorant chemicals at different concentrations. When incorporated into a formulation, the individual fragrance chemicals partition between the emulsion phases depending on their physicochemical properties, which can impact the structure, stability, texture and odour of the final product. On the other hand, it is well known in the food industry how the composition and structure of food emulsion matrices influence the release of aroma chemicals. Fragranced dermocosmetic emulsions have been studied to a lesser extent but it is interesting to apply findings from the food domain since emulsion structure, composition and aroma compounds share common features. This review aims to give an overview of the literature dealing with the interactions between fragrance and dermocosmetic emulsions. The effects of fragrance on emulsion microstructure, stability and texture are highlighted and discussed. The effects of composition and structure of emulsion on the release of fragrance molecules are also presented. Finally, the interactions between skin and fragranced emulsions are addressed.Résumé Des parfums sont ajoutés dans la plupart des émulsions dermocosmétiques. L'odeur d'un produit est en effet un facteur déterminant lors du choix par les consommateurs, et elle peut même contribuer à la perception de ses performances. Le parfum est un mélange complexe de substances chimiques odorantes à différentes concentrations. Lorsqu'elles sont incorporées dans une formule, les molécules odorantes se répartissent entre les phases de l'émulsion en fonction de leurs propriétés physicochimiques, ce qui peut avoir un impact sur la structure, la stabilité, la texture et l'odeur du produit fini. D'autre part, il est bien connu dans l'industrie alimentaire que la composition et la structure des matrices alimentaires influencent la libération des molécules aromatiques. Les émulsions dermocosmétiques parfumées ont été moins étudiées dans la littérature, mais les résultats obtenus dans le domaine alimentaire peuvent être utiles pour comprendre les phénomènes mis en jeu dans ces systèmes. En effet, la structure et la composition des deux types d'émulsions, et la nature des composés aromatiques et odorants présentent de nombreuses caractéristiques communes. Cette revue vise à donner une analyse de la littérature traitant des interactions entre les parfums et les émulsions dermocosmétiques. Dans un premier temps, les effets des parfums sur la microstructure, la stabilité et la texture des émulsions sont présentés et discutés. Puis, les effets de la composition et de la structure de l'émulsion sur la libération des molécules parfumantes sont abordés. Enfin, les interactions entre la peau et les émulsions parfumées sont renseignées

Effect of linalool on lamellar-structured emulsions: From molecular organization to organoleptic properties

International audienc

Acta Psychiatr Scand

INTRODUCTION: Depression is one of the most common co-morbidities during pregnancy; with severe symptoms, antidepressants are sometimes recommended. Social determinants are often linked with antidepressant use in the general population, and it is not known if this is the case for pregnant populations. Our objective was to determine if social determinants are associated with prenatal antidepressant intake via a systematic review and meta-analysis. METHODS: A systematic search of five databases was conducted to identify publications from inception to October 2022 that reported associations with prenatal antidepressant intake (use/continuation) and one or more social determinants: education, race, immigration status, relationship, income, or employment. Eligible studies were included in random effects meta-analyses. RESULTS: A total of 23 articles describing 22 studies were included. Education was significantly and positively associated with prenatal antidepressant continuation and heterogeneity was moderate. (Odds ratio = 0.83; 95% CI, 0.78 to 0.89; p < 0.00001; I(2)  = 53%). Meta-analyses of antidepressant use and education, race, and relationship status, and antidepressant continuation and income were not significant with high levels of heterogeneity. DISCUSSION: While most social determinants in this review were not linked with prenatal antidepressant intake, lower maternal education level does seem to be associated with lower rates of prenatal antidepressant continuation. CONCLUSIONS: Education appears to be linked with prenatal antidepressant intake. The low number of included studies precludes conclusive evidence for other social determinants.Troubles de l'humeur et de l'anxiété maternelles prénatales et leur traitement, impact sur le développement de l'enfan

Pathways between Risk/Protective Factors and Maternal Postnatal Depressive Symptoms: The ELFE Cohort

International audienceObjective: The risk factors for postnatal depressive symptoms (PNDS) are numerous, but little is known about the protective factors or the interactions between different exposures. The present study explored the pathways between maternal, infant and parenthood vulnerabilities or risk/protective factors and PNDS at 2 months postpartum (PP) in a large sample of women from the general population. Methods: We used data from the French ELFE cohort, a nationally representative cohort of children followed-up from birth. The available information about vulnerabilities or risk/protective factors for PNDS was collected during the maternity ward stay (mother or medical records) and at 2 months PP (mother by phone). PNDS were evaluated with the Edinburgh Postnatal Depression Scale (EPDS) at 2 months. A measurement model was built based on the psychosocial model for PNDS of Milgrom and colleagues using exploratory factor analysis. The Structural Equation Model was used to investigate the pathways between vulnerability, risk/protective factors and PNDS at 2 months PP. Results: In the study sample (n = 11,583), a lack of a partner’s perceived antenatal emotional support, consultation with a mental health specialist before pregnancy, family financial difficulties, prenatal psychological distress and a difficult pregnancy experience were directly associated with the severity of maternal PNDS at 2 months PP, as well as lack of perceived postnatal support. Family financial difficulties and consultation with a mental health specialist before pregnancy were also indirectly associated with the intensity of PNDS through a lack of perceived antenatal emotional support, a difficult pregnancy experience, prenatal psychological distress and a lack of perceived postnatal support. Regarding infant and parenthood characteristics, infant self-regulation difficulties, maternal difficulty in understanding infant crying and infant hospitalisation were directly associated with PNDS severity at 2 months PP, while maternal difficulty in understanding an infant’s cries was also indirectly associated with infant self-regulation difficulties. Conclusions: Perinatal professional support should begin antenatally and target the couple’s prenatal functioning, with particular attention to women presenting a history of psychiatric disorders, especially those of low socioeconomic status. After delivery, addressing infant and parenthood characteristics is also recommended

Women and health professionals’ perspectives on a conditional cash transfer programme to improve pregnancy follow-up: a qualitative analysis of the NAITRE randomised controlled study

Objectives Women of low socioeconomic status have been described as having suboptimal prenatal care, which in turn has been associated with poor pregnancy outcomes. Many types of conditional cash transfer (CCT) programmes have been developed, including programmes to improve prenatal care or smoking cessation during pregnancy, and their effects demonstrated. However, ethical critiques have included paternalism and lack of informed choice. Our objective was to determine if women and healthcare professionals (HPs) shared these concerns.Design Prospective qualitative research.Setting We included economically disadvantaged women, as defined by health insurance data, who participated in the French NAITRE randomised trial assessing a CCT programme during prenatal follow-up to improve pregnancy outcomes. The HP worked in some maternities participating in this trial.Participants 26 women, 14 who received CCT and 12 who did not, mostly unemployed (20/26), and - 7 HPs.Interventions We conducted a multicentre cross-sectional qualitative study among women and HPs who participated in the NAITRE Study to assess their views on CCT. The women were interviewed after childbirth.Results Women did not perceive CCT negatively. They did not mention feeling stigmatised. They described CCT as a significant source of aid for women with limited financial resources. HP described the CCT in less positive terms, for example, expressing concern about discussing cash transfer at their first medical consultation with women. Though they emphasised ethical concerns about the basis of the trial, they recognised the importance of evaluating CCT.Conclusions In France, a high-income country where prenatal follow-up is free, HPs were concerned that the CCT programme would change their relationship with patients and wondered if it was the best use of funding. However, women who received a cash incentive said they did not feel stigmatised and indicated that these payments helped them prepare for their baby’s birth.Trial registration number NCT0240285