INTERACTION OF INDOMETHACIN WITH A NEW PENETRATION ENHANCER, DODECYL 2-(N,N-DIMETHYLAMINO)PROPIONATE (DDAIP) - ITS EFFECT ON TRANSDERMAL DELIVERY

The new biodegradable penetration enhancer DDAIP (dodecyl 2-(N,N-dimet hylamino)propionate) shows a striking enhancement of the acidic drug i ndomethacin through shed snake skin. This enhancement appears-to be du e partially to some interaction between the drug and the enhancer. Thi s interaction was examined using UV, IR, H-1- and C-13-NMR spectrometr y and differential scanning calorimetry (DSC). The existence of prefer ential hydrogen bonding between the carboxylic acid group of indometha cin and the tertiary amine group of the enhancer and a dipole-dipole i nteraction was demonstrated.