Cosmeceutical Formulation Considerations

Published on 15/03/2015 by admin

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Last modified 15/03/2015

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Chapter 3 Cosmeceutical Formulation Considerations

VEHICLES

The primary purpose of the vehicle is to optimize the delivery of ‘cosmeceutical’ benefits to the consumer. These usually involve providing immediate or short-term benefits as well as benefits that take 30–60 days to manifest. All this is done while insuring that the formulations are safe for use as well as preserved against potential microbial contamination.

The most common, and still the most efficacious, vehicle is the emulsion. However, this category has seen tremendous growth by the inclusion of silicone-in-water emulsions, water-in-silicone emulsions, and nonaqueous emulsions that use oils/silicones in combination with glycols or other polyols. The increased use of silicones has expanded the types of formulation being introduced, resulting in an increase in products that are now referred to as ‘serums’. A serum, like a ‘lotion’ or a ‘cream’, has no legal definition but has become associated with formulations that are generally low-viscosity translucent liquids. They are frequently used in eye treatment products and specialty applications to the face (i.e. spot treatments etc.).

In the previous chapter on this subject, written by my colleague and friend, Ken Klein, he described what constitutes an oil-in-water emulsion (O/W), water-in-oil emulsion (W/O), liquid crystal stabilized emulsions, and multiphase emulsions (W/O/W). We are going to expand on that and include some of the current formulation trends in these categories.

• Emulsions

OIL-IN-WATER EMULSIONS

The challenges that are present in the current development of oil-in-water (O/W) emulsions are the increased use of silicone and silicone polymers in these types of formulation. Generally speaking, many of the silicone ‘oils’, polymers and elastomers have very poor compatibility with typical organic ‘oils’ or esters. The challenge is in the selection of the emulsifier system and the combination of hydrophobic materials that will allow for a homogeneous and uniform internal oil phase. In addition, this phase is also a delivery system for a number of functional ‘active’ ingredients, enhancing their functionality and performance.

The choice of ingredients now needs to consider the effect on performance as well as aesthetics. Figure 3.1 is an O/W emulsion in which the predominant components of the oil phase are a blend of silicones. This emulsion can be modified with the addition of bioactive ingredients—antioxidants and skin-soothing ingredients. The other aspect of this formulation that is worth noting is the use of an emulsion-stabilizing system that can be added at the end. This ingredient serves a dual function—adjusting viscosity and improving emulsion stability. Care must be taken, however, because these emulsion-stabilizing systems can also affect the feel of the product.