MRI as a promising tool for evaluation of the stability of cosmetic emulsions

作者：Onuki Y; Kida C; Funatani C; Hayashi Y; Takayama K

来源：International Journal of Cosmetic Science, 2016, 38(3): 272-278.

DOI：10.1111/ics.12290

• chemical analysis
• Formulation skin care
• stability
• texture
• emulsions
• milky lotion
• MRI
• NMR/FTIR/MASS spectroscopy

ObjectiveWe have recently established a novel method to evaluate the emulsion stability of pharmaceutical skin cream. The key technology of the method is magnetic resonance imaging (MRI). The purpose of this study was to verify the usefulness of the method in the cosmetic industry.
MethodsMilky lotion-type emulsions were employed as test samples. We note that the test samples were prepared by taking account of commercial milky lotions. After the sample preparation, a centrifugation treatment (5000g for up to 120min) was implemented to accelerate their destabilization processes. The centrifuged samples were monitored by using T-2 relaxation time (T-2) maps. Furthermore, the histograms generated from the T-2 maps were analysed to investigate the destabilization process in more detail. In addition, small fractions of the upper and lower phases were collected from the centrifuged samples, and microscopic observations were conducted.
ResultsT(2) maps successfully visualized the destabilization process accompanying the centrifugation protocol. From the microscopic observations, it was clarified that the main mechanism of the destabilization process was creaming. The sensitivity of the T-2 map to creaming was much superior to that of visible observation; the T-2 map can detect a slight creaming that is not visible to the naked eye. In addition, the T-2 map also enables the detection of slight reversible creaming-dispersion changes accompanied by a repeated centrifugation-vortexing treatment. By using the parameters derived from the histogram analysis, the creaming behaviour can be evaluated more precisely and more objectively. This study prepared emulsions containing different thickener contents and then compared their creaming behaviours. As a consequence of the analysis, we could fully evaluate the effect of thickener on the emulsion stability by the evaluation method.
ConclusionMRI is a promising tool for evaluation of the stability of cosmetic emulsions.
Resume
ObjectifNous avons recemment developpe une nouvelle methode pour evaluer la stabilite de l'emulsion de cremes pharmaceutiques pour la peau. La technologie cle du procede est l'imagerie par resonance magnetique (IRM). Le but de cette etude est de verifier l'utilite du procede dans l'industrie cosmetique.
MethodesDes emulsions de type lotion laiteuse ont ete utilisees comme echantillons d'essai. Nous notons que les echantillons d'essai ont ete prepares en tenant compte des lotions laiteuses commerciales. Apres la preparation de l'echantillon, un traitement de centrifugation (5000g jusqu'a 120min) a ete effectue pour accelerer leur processus de destabilisation. Les echantillons centrifuges ont ete controles en utilisant des cartes de temps de relaxation T2 (T2). En outre, les histogrammes generes par les cartes T2 ont ete analyses pour etudier le processus de destabilisation dans le detail. En plus, de petites fractions des phases superieures et inferieures ont ete recueillies a partir des echantillons centrifuges et des observations microscopiques ont ete realisees.
ResultatsLes cartes T2 visualisaient avec succes le processus de destabilisation accompagnant le protocole de centrifugation. D'apres les observations microscopiques, il etait clair que le principal mecanisme du processus de destabilisation a ete l'ecremage. La sensibilite de la carte de T2 a ecremage etait bien superieure a celle de l'observation visible; la carte de T2 peut detecter un leger ecremage qui n'est pas visible a l'OEil nu. EN plus, les cartes T2 permettent la detection de legers changements reversibles d'ecremage/dispersion accompagnes par un traitement repete centrifugation-vortex. En utilisant les parametres issus de l'analyse de l'histogramme, le comportement d'ecremage peut etre evalue de maniere plus precise et plus objective. Cette etude a prepare des emulsions contenant differentes teneurs en epaississant puis a compare leurs comportements a l'ecremage. En consequence de cette analyse, nous pourrions evaluer pleinement l'effet d'epaississant sur la stabilite de l'emulsion par la methode d'evaluation.
ConclusionL'IRM est un outil prometteur pour l'evaluation de la stabilite des emulsions cosmetiques.

• 出版日期2016-6