New transdermal and transmucosal nitroglycerin delivery systems in patients with ischaemic heart disease

The efficacy of a transdermal (Nitroderm-TTS) and a transmucosal (Trinitrolong) nitroglycerin (NG) formulation has been compared with sublingual NG in 9 patients with ischaemic heart disease and stable angina pectoris. The duration and the degree of anti-ischaemic effect were assessed in terms of similar, individually adjusted work loads performed prior to and repeatedly after drug application in comparison with placebo. The anti-ischaemic effect of nitroderm appeared in 0.5-3 h after administration, reached a maximum in about 3.8 h and persisted for 7.9 h. The maximal nitroderm effect was significantly lower than that of sublingual NG or Trinitrolong. The effect of Trinitrolong was less variable and lasted for 4.6 h. It was evident in all patients 0.5 h after drug administration. Plasma NG levels were monitored in 9 patients after sublingual NG and trinitrolong and in 4 following Nitroderm. The relative bioavailability of Nitroderm and Trinitrolong according to the pharmacokinetic data was 29% and 256%, respectively, of sublingual NG tablets. A therapeutic NG level in blood (0.5 ng/ml) after Trinitrolong appeared much earlier (2 min) than after Nitroderm (1 h). A significant reduction in the effect of sublingual NG was observed during Nitroderm application. Thus, the transdermal NG formulation did not exhibit an antianginal effect lasting for 24 h; transmucosal NG had a relatively short, but more pronounced and stable antianginal effect.