Design and application of water-in-oil emulsions for use in lipstick formulations

BJD Le Reverend, MS Taylor, Ian Norton

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Synopsis The addition of water to lipsticks in the form of a water-in-oil emulsion is an attractive opportunity for cosmetics manufacturers to deliver hydrophilic molecules to the consumers, as well as improving the moisturizing properties. In this work, the effect of the emulsifier type and water content on the structural properties of the designed products was investigated. It has been shown that PGPR leads to smaller droplets than the other emulsifiers tested. This was attributed to the ability of PGPR to form elastic interfaces that slow the coalescence between droplets during the process. It was also observed that crystals of wax tend to form structures at the interface upon cooling that prevent coalescence during storage. These structures also prevent leakage of water into the continuous phase. No effect of the water content on the melting properties of the emulsions was observed. Upon addition of more than 10% water, softening of the material was measured, due to the overall decrease in solid content. Addition of crystalline material (hard paraffin) was successfully used to reinstate the material properties.Resume L'utilisation d'eau comme ingredient dans des formulations de rouges a levres sous la forme d'une emulsion represente l'opportunite pour l'industrie cosmetique de delivrer des molecules hydrophiles aux consommateurs, ainsi que d'ameliorer leurs proprietes humectantes. Au cours de ce travail, l'effet du type de surfactant ainsi que le volume occupe par la phase dispersee sur la structure de l'emulsion obtenue ont eteetudies. Nous avons observe que les gouttelettes les plus fines furent obtenues avec l'utilisation du surfactant PGPR. Les proprietes elastiques des interfaces stabilisees par le PGPR permettent de limiter la coalescence entre gouttelettes et donc d'obtenir une taille moyenne plus fine. Nous avons aussi observe que les cristaux de cire de la phase continue pouvaient stabiliser l'emulsion via la formation de structures secondaires aux interfaces. Ces structures, semblables a des coques permettent de limiter la migration d'eau entre la phase dispersee et la phase continue. D'un point de vue thermodynamique, l'ajout d'eau n'a pas d'effet sur les proprietes de changement de phase de la phase continue, probablement grace a cette barriere a l'interface. Au dela de 10% de phase dispersee, un ramollissement du produit final par rapport a un echantillon controle a pu etre mesure. Ceci peut etre corrige en modifiant la phase continue par ajout de matiere cristalline (paraffine).
Original languageEnglish
Pages (from-to)263-268
Number of pages6
JournalInternational Journal of Cosmetic Science
Volume33
Issue number3
DOIs
Publication statusPublished - 1 Jun 2011

Keywords

  • lipsticks
  • wax
  • PGPR
  • emulsion
  • span

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