MedicalResearch.com Interview with: Audra Stinchcomb, PhD Principal Investigator Professor of Pharmaceutical Sciences University of Maryland School of Pharmacy MedicalResearch.com: What is the background for this study?   Response: We have been studying the heat effects and repeated dose effects on the absorption of drugs across the skin for more than 5 years.  We were curious to see if the effects we saw on gel, cream, and ointment pharmaceuticals also occurred with sunscreen. Sunscreens are typically used in the hot sun and with reapplication every 80 minutes or so, depending on the product and user.