Nitroglycerin has been the agent of choice for the treatment of angina pectoris for over 100 years. In recent years various long-acting preparations have been introduced for the prophylaxis of angina pectoris and most recently for use in the long term management of a patient with left ventricular dysfunction. These long-acting preparations including nitroglycerin ointment, slow release oral nitroglycerin, and “ long-acting” nitrates, such as isosorbide dinitrate and pentaerytritol trinitrate have found wide acceptance. The effectiveness and acceptance of these preparations is, however, limited by the need to administer them every 4–6 h with resultant difficulties in patient compliance and variation in absorption. Variation in absorption is found with the oral preparations but may be worse with the use of ointments which are often applied in a variable manner from application to application. This paper reports upon the development and initial human use of a new topical drug delivery system for nitroglycerin with a duration of action of a minimum of 24 h.