O/W/S multi-emulsion stability and skin penetration (2025)

Introduction

Multi-emulsion is a formulation used to maintain the stability of active ingredients and increase delivery efficiency in cosmetics and drug delivery systems. In particular, O/W/S multi-emulsion is effective in protecting active ingredients from the external environment through their unique structure. However, the existing manufacturing method has problems with high energy loss and CO2 emissions due to complex processes and high temperatures. To solve this, this study introduced D-phase emulsion technology to simplify the manufacturing process. It was proposed to improve stability.

Research Methods

In this study, D-phase emulsion technology and conventional O/W emulsion methods were compared to analyze the manufacturing process and stability of O/W/S multiple emulsions. Three types of emulsions (Type A, B, and C) were prepared to experimentally evaluate the stability and skin permeability. Type A (D-phase O/W/S multiple emulsion) was prepared using the D-phase emulsion method at low temperature (40°C).Type B (general O/W/S multiple emulsion) is prepared with an internal O/W emulsion at a high temperature of 70°C using the existing O/W method, and then mixed with the outer layer to complete the multiple emulsion. Type C (simple O/W emulsion) has a simple O/W structure and is manufactured in a conventional way.

To evaluate the stability of the emulsion, each sample was stored at 25°C and 43°C for 4 weeks, and the change in retinol content was measured through HPLC analysis. The size and density of the emulsion particles were observed using an optical microscope.

As a result of the study, the type A emulsion (D-phase method) showed the highest stability when stored at 43°C for 4 weeks, retaining 58.73% of retinol. Type B (general O/W/S method) showed a retention rate of 25.63%, and type C (simple O/W emulsion) recorded the lowest value at 7.47%. Type A, manufactured by the D-phase method, has a small particle size and high density, which has been confirmed to be effective in maintaining the stability of the active ingredient.

In terms of skin permeability, the skin permeability of A, B, and C was 14.27%, 15.81%, and 13.62%, respectively.

Improved stability

The type A multi-emulsion prepared by the D-phase emulsion method retains 58.73% of the retinol even under harsh conditions such as 43°C, showing significantly higher stability than type B (25.63%) and type C (7.47%). This is because the D-phase method forms the inner O/W particles into a smaller, denser form, providing a physical barrier for the active ingredient to be protected from the external environment. These results are consistent with previous studies that show that the structural properties of multiple emulsions have an important impact on the stability of the active ingredient.

Limitation of skin delivery efficiency

Franz cell experiments showed no significant difference in skin permeability between types A, B, and C, suggesting that multiple emulsions may not necessarily show superior results in the skin delivery system. This suggests that the structural complexity of multiple emulsions may have played a role in limiting the skin permeation pathway, or maintaining the delivery rate of the active ingredient at a constant level. However, the fact that multiple emulsions do not have an advantage in skin delivery efficiency does not need to be interpreted as a disadvantage in itself. Rather, This means that it can play a positive role in regulating the release rate of active ingredients or maintaining long-term stability under certain conditions.

Manufacturing Process and Sustainability

The D-phase method simplifies the process, reduces energy consumption, and effectively reduces CO2 emissions compared to traditional high-temperature (70~80°C) manufacturing methods. This method is energy-saving by performing the process at a low temperature of 40°C, and minimizes cleaning and time waste during the manufacturing process by using a single mixer. These characteristics provide great advantages in an environment where more and more consumers and companies demand sustainable products and processes.

Conclusion

This study innovatively improved the manufacturing process of O/W/S multi-emulsion by utilizing the D-phase emulsion method. This method provides a sustainable manufacturing process that reduces energy consumption and reduces CO2 emissions by enabling manufacturing at low temperatures. In addition, the D-phase method has been shown to significantly improve the stability of the active ingredient compared to conventional manufacturing methods. In terms of skin delivery efficiency, multi-emulsion has shown a similar level of performance to simple O/W emulsions, It was confirmed that the multi-emulsion structure is effective in protecting the active ingredient and increasing its stability. This shows the potential for multi-emulsion to be used in cosmetics and drug delivery systems in the long term.

In conclusion, the D-phase emulsion method overcomes the technical and environmental limitations of the multi-emulsion manufacturing process and will provide an important foundation for the future of sustainable cosmetics and drug delivery systems.

O/W/S 멀티 에멀젼의 안정성 및 피부 침투력 < SPECIAL < 기사본문 - THE K BEAUTY SCIENCE