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Painless, noninvasive and sustained self-administered therapeutics are becoming increasingly popular as the drug technologies of the new millennium. Transdermal delivery systems are now emerging as promising candidates in this search. The concept of topical drug administration on human skin has been prevalent since the rise of early human civilization. It is in the early 1800’s, however, that researchers seriously considered skin as a medium for systemic therapeutics. Two centuries later, this thought has culminated in less than a handful of transdermal products in the market. This is not surprising given the paradoxical nature of this idea: we desire to drive foreign material (therapeutics) through an intricate and densely packed membrane (skin), which is precisely designed to keep them out! The biggest challenge in putting this idea to work is to sufficiently open up the skin to move drug molecules across it but while doing so cause no harm to the basic evolutionary function of skin: protect us from the atrocities of a hostile environment of bacteria, viruses and toxics.
It is this hurdle that has proved the stranglehold on any success with the transdermal technology.

We put forth an elegant way of striking that balance by using unique and rare mixtures of chemicals. Such chemical mixtures, called SCOPE (Synergistic Combinations Of Penetration Enhancers) formulations, exist rarely and the only way to discover all of them is to screen about 30 million candidates. INSIGHT screening, developed in our lab, makes a strong headway towards screening this vast library in a reasonable time frame. Increased efficiency is possible with parallel testings (1500 at a time) and a surrogate endpoint, conductivity, as a measure of skin "pervasion" of drug molecules. Concurrently, the design of INSIGHT screening highly emphasizes the thrift in use of skin as a model for all testing. We have shown that INSIGHT screening leads to discovery of SCOPE formulations that can be used to deliver therapeutics, previously administered only as injectables. Improved systemic therapeutics is only one facet of an alarmingly complex puzzle that INSIGHT screening addresses. Skin is a highly complicated biological system, which we still do not fully understand. To design curatives for skin, from cosmetics to therapeutics, then, brute force testing is the only viable option. INSIGHT screening is precisely the approach that helps us study the effect of test formulations on a desired property of skin in a rapid and efficient manner. In doing so we not only benefit from the discovery of new and improved skin curatives but we also keep adding to our knowledge of how the skin interacts with different entities that it comes in contact with. This information significantly reduces the cost and effort of designing cosmetics and therapeutics for use on skin.