Abstract: A transdermal delivery system of isosorbide dinitrate (ISDN-TDS)and an HPLCmethod for the measurement of ISDN were developed. The system is composed of backing.drug reser-voir,control membrane, contact adhesive and protective layer. The influences of drug reservoir, solvent, control membrane, viscosity and penetration enhancerazone on the release of ISDN were investigated. The cumulative released amount of ISDN / time profile indicated that ISDN was permeatedthrough excised skin in a zero--order kinetic in 48 h. The release of ISDN from ISDN--TDS can last72 h at least. The mean permeation rate is 13.76 μg·h^-1/cm². Releasing ISDN from ISDN--TDSwas more stable than that from Frandol tape-s whose release profile was found to follow a linear Q vst^1/2 relationship witha release flux of 114.39 μg·h^-1/cm².