{"id":9837,"date":"2019-09-20T08:00:01","date_gmt":"2019-09-20T14:00:01","guid":{"rendered":"https:\/\/www.ulprospector.com\/knowledge\/?p=9837"},"modified":"2022-06-15T06:13:55","modified_gmt":"2022-06-15T12:13:55","slug":"pcc-how-to-improve-the-bioavailability-and-efficacy-of-skin-care-actives","status":"publish","type":"post","link":"https:\/\/ulprospector.ul.com\/9837\/pcc-how-to-improve-the-bioavailability-and-efficacy-of-skin-care-actives\/","title":{"rendered":"How to improve the bioavailability and efficacy of skin care actives"},"content":{"rendered":"

\"GroupImproving active bioavailability is key to improving the efficacy of skin care formulations. When products are clinically tested, subjects can normally be grouped into low, medium and high responders. By decreasing the number of low responders and increasing high responders, clinical efficacy can be dramatically improved.<\/p>\n

I believe that much of the subject variability can be attributed to poor bioavailability of low responders. For example, benzophenone skin penetration has a subject variability of 6 ug\/cm2 to 40 ug\/cm2 penetrating in 48 hours on the same skin site. Best in class skin repair actives can reduce wrinkle depth in high responders by up to 60%, but only approximately 30% when averaged with low and medium responders. This suggests that improving bioavailability of an existing active by increasing the number of high responders may be a better strategy than developing new actives.<\/p>\n

What is \u201cbioavailability?\u201d<\/h3>\n

Bioavailability is defined as the penetration rate for an active to reach its site of action. This is also referred to as the flux rate or the amount of active penetrating over time (micrograms\/cm2\/hour). For cosmetic actives, the target usually is the lower epidermis. However, for ingredients like sunscreens, the goal is to stay on the surface of skin to assure maximum UV absorption. The challenge in formulating highly effective skin care products is getting superior bioavailability while minimizing irritation caused by other formulation ingredients that may also have penetrated. In pharmaceutics this is referred to as the therapeutic index or the benefit\/risk ratio. For skin care products, unlike drugs, only an extremely low level of risk is acceptable.<\/p>\n

Three factors that control the penetration rate of actives<\/h3>\n

The three most important factors that control the skin penetration of actives are molecular weight, C log P and charge (anionic or cationic). The highest molecular weight that an uncharged active can normally penetrate is approximately 500 Daltons. C log P is a measure of the hydrophobicity of a molecule as measured by the log of its solubility in Octanol divided by its solubility in water. Low or too high hydrophilicities can cause poor penetration. It has been shown for compounds to have a reasonable probability of penetrating, their C log P value must be between 1 and 5(1).<\/sup><\/p>\n

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Looking for actives for use in cosmetic formulations?<\/h3>\n

Prospector can help you find the actives you need for your next formulation. Find technical data, request samples, and connect with global suppliers in just a few clicks.<\/p>\n

Search for actives on Prospector.<\/a><\/h3>\n
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What formulations affect bioavailability?<\/h3>\n

Different types of formulations can demonstrate significant differences in bioavailability. These include oil in water, water in oil, water in oil in water, polyol in oil emulsions and hydrogels.<\/p>\n

Most methods that increase bioavailability cause a disruption of the skin\u2019s barrier function or work by increasing active solubility in water or oil.<\/p>\n