Temperature affects drug penetration by two mechanisms. Firstly it alters the physiology of the skin, and secondly the physicochemical diffusion rates in the device increase with temperature. The skin temperature is strongly influenced by its surroundings, and may be 20°C cooler than body temperature or several degrees hotter. Fortunately many transdermal patches act as insulators and so the actual variation beneath the device is likely to be significantly lower. The external temperature is more likely to influence the diffusion rate in the controlled release system itself. In disease the body temperature may vary;

temperature-induced variations in the diffusion coefficient may alter the absorption rate by up to a factor of two over this temperature range20.

Temperature also influences blood flow in the surface vasculature and so might be expected to influence adsorption through this route. However, this possibility has not yet been proven21 and since the device and the stratum corneum are rate-limiting, the effects of blood flow might be expected to be minimal.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

Get My Free Ebook

Post a comment