Transkarbam 12, an ammonium carbamate formed by the reaction of dodecyl 6- aminohexanoate with carbon dioxide, is a highly active, broad-spectrum, nontoxic, and nonirritant transdermal permeation enhancer. It probably acts by a dual mechanism: a part of its activity is associated with the carbamic acid salt and/or its decomposition in the acidic stratum corneum. The ammonium ester thereby released is an active enhancer species as ...