Angina pectoris is defined as chest pain due to lack of blood and oxygen to the heart. Nitroglycerin is an organic nitrate which treats angina by vasodilating both arteries and veins to increase blood flow to the heart. It is easy to develop nitroglycerin drug tolerance, and therefore drug application must occur at intervals of about 12 hours.
While commercial products such as Deponit are suitable for treating mild cases of angina, a larger, daily dose of 40 mg of nitroglycerin is needed to treat the most acute cases. The purpose of this study is to model the diffusion of nitroglycerin from a transdermal patch into the blood stream using the Deponit drug delivery system. We determined that Deponit was indeed unable to deliver the necessary 40 mg of drug. We therefore suggested a new patch which could treat acute angina, by modifying both patch geometry and the initial amount of drug in the reservoir. We also simulated drug delivery for a 36 hour period of wearing the patch for 12 hours, not wearing the patch for 12 hours, and then reapplying a new patch for another 12 hours. We found that drug continued to be delivered even in absence of patch and after 36 hours, only ~125 mg of drug was delivered. The modified Thicker Patch with a 10x thicker drug reservoir than Deponit can physically hold 142 mg of drug and deliver 40 mg within 12 hours. The modified patch is safe, non-toxic, cost effective, and capable of treating recalcitrant angina. To determine whether our assumptions were appropriate for our parameters, we performed two specific sensitivity analyses: varying the diffusivity of the skin and varying the diffusivity of the patch and the skin. From the sensitivity analysis we found that the amount of drug delivered to body is very sensitive to the diffusivity of the skin but insensitive to the diffusivity of the patch