Optimization and development of stable w/o/w cosmetic multiple emulsions by means of the Quality by Design approach

A. Kovács, I. Erös, I. Csóka

Research output: Contribution to journalArticle

13 Citations (Scopus)


Synopsis Objectives The aim of our present work was to develop stable water-in-oil-in-water (w/o/w) cosmetic multiple emulsions that are proper for cosmetic use and can also be applied on the skin as pharmaceutical vehicles by means of Quality by Design (QbD) concept. This product design concept consists of a risk assessment step and also the 'predetermination' of the critical material attributes and process parameters of a stable multiple emulsion system. We have set up the hypothesis that the stability of multiple emulsions can be improved by the development based on such systematic planning - making a map of critical product parameters - so their industrial usage can be increased. Methods The risk assessment and the determination of critical physical-chemical stability parameters of w/o/w multiple emulsions to define critical control points were performed by means of quality tools and the leanqbd (QbD Works LLC, Fremont, CA, U.S.A.) software. Results Critical materials and process parameters: Based on the results of preformulation experiments, three factors, namely entrapped active agent, preparation methodology and shear rate, were found to be highly critical factors for critical quality attributes (CQAs) and for stability, whereas the nature of oil was found a medium level risk factor. The results of the risk assessment are the following: (i) droplet structure and size distribution should be evaluated together to be able to predict the stability issues, (ii) the presence of entrapped active agents had a great impact on droplet structure, (iii) the viscosity curves represent the structural changes during storage, if the decrease in relative viscosity is >15% the emulsion disintegrates, and (iv) it is enough to use the shear rate between 34g and 116g relative centrifugal force (RCF). CQAs: By risk assessment, we discovered that four factors should be considered to be high-risk variables as compared to others: droplet size, droplet structure, viscosity and multiple character were found to be highly critical attributes. Conclusion The preformulation experiment is the part of a development plan. On the basis of these results, the control strategy can be defined and a stable multiple emulsion can be ensured that meets the relevant stakeholders' quality expectations.

Original languageEnglish
Pages (from-to)128-138
Number of pages11
JournalInternational Journal of Cosmetic Science
Issue number2
Publication statusPublished - Apr 1 2016


  • droplet size
  • multiple emulsion
  • Quality by Design concept
  • risk assessment
  • stability
  • viscosity

ASJC Scopus subject areas

  • Dermatology
  • Colloid and Surface Chemistry
  • Ageing
  • Drug Discovery
  • Pharmaceutical Science
  • Chemistry (miscellaneous)

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