Synthesis and transdermal penetration-enhancing activity of carbonic and carbamic acid esters--comparison with transkarbam 12.

Transkarbam 12 (T12) is a novel transdermal penetration enhancer with high activity. Its polar head group is formed by carbamic acid salt that is unstable in acidic environment and releases CO(2). To find out whether this property influences its high activity, two series of compounds with CO(2) stronger bound in the polar head have been prepared-carbonic and carbamic acid esters. The carbamate salt in the polar head was found to be essential for the enhancing activity and its decomposition in an acidic environment suggested relating to the mode of action of T12.