paulking

Penetration Enhancers

One long-standing approach for improving [absorption through skin] uses
penetration enhancers (also called sorption promoters or accelerants)
which penetrate into skin to reversibly decrease the barrier resistance.

— Scientists with the School of Pharmacy, University of Bradford, UK
(Williams and Barry 2004)

...Bisabolol is a penetration enhancer... Noting that Bisabolol is used in
baby lotions the Panel cautioned formulators to the possibility of
increased absorption of other ingredients also contained in the
formulation, especially those ingredients whose safety is based on their
lack of dermal absorption.

— Cosmetic industry safety panel, the Cosmetic Ingredient Review (CIR
2003)

For more than 20 years drug companies have used penetration enhancing
chemicals to deliver patch drugs like birth control and nicotine deeper
and faster through the skin and into the blood vessels below. In some
cases penetration enhancers increase absorption of a drug by 100-fold
relative to absorption without the enhancer (Karande et al. 2004).

Although not necessarily added to cosmetics for the purpose of enhancing
penetration, many ingredients used in cosmetics happen to have that
property. A recent review of penetration enhancers by scientists at the
Drug Delivery Group at the University of Bradford, West Yorkshire, UK,
notes common cosmetic chemicals that are used in drug delivery
applications (propylene glycol and sodium lauryl sulfate, for example)
(Williams and Barry 2004). The cosmetic industry's safety panel has
acknowledged the use of penetration enhancers in cosmetics, and warns the
industry to consider their effect in combination with ingredients the
panel deemed safe based on an assumption of low absorption.

Health concerns with penetration enhancers do not necessarily revolve
around the toxicity of the enhancer itself, but instead with what it
brings with it as it opens the skin up for greater absorption. In our
assessment of 7,500 personal care products, we found that penetration
enhancers are used in products that also contain ingredients with
significant potential health concerns:

* Fifty-six percent of 7,500 products examined contain ingredients that
are penetration enhancers, according to data presented in CIR (2003) and
peer-reviewed sources.
* 50 products contain penetration enhancers in combination with known or
probable human carcinogens (Table 1).
* 7 products contain penetration enhancers in combination with known or
probable reproductive toxins (Table 2).
* 120 products contain penetration enhancers in combination with chemicals
considered safe for use in cosmetics in part because of assumed low
absorption through the skin (Table 3).
*
Table 1. Penetration enhancers are found in products that contain known or
probable carcinogens.

34 (0.5%) products contain penetration enhancers in combination with known
or probable carcinogens. List all products.

Category Percent of Products

Menopause Cream 54.5%*(6


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Another study used the 200 times figure I mentioned. I will try to find
and post it too. Karande et al (above) estimate a 100 -fold increase in
absorbtion.