Transdermal Scopolamine Drug Delivery Systems for Motion Sickness

Transdermal drug delivery systems are involved in the continuous administration of drug molecules from the surface of the skin into the circulatory system. Such systems have proved advantageous for delivery of certain drugs, such as scopolamine, nicotine, nitroglycerine, and estradiol. Compared with oral administration, transdermal drug delivery offers better uniformity of drug concentrations in plasma throughout their duration of use. Scopolamine is the active ingredient in motion sickness medication that targets the nerve fibers in the inner ear. The scopolamine patch is effective for about three days, longer than if administered orally which is effective for only several hours. One of the main restraints of this transdermal system is its absorption through the skin, especially through the stratum corneum, its outermost part. This study examines the rate of diffusion of transdermal scopolamine across the skin and into the systemic circulation. Our objective is to optimize the drug delivery by way of a scopolamine patch by minimizing absorption rates, while maintaining its advantage of a long-term effect. A comparative study of the effects in the presence of penetration enhancers were undertaken to show how steady state is approached at different rates. The model we used does offer certain limitations, as diffusivity values specific to human skin and scopolamine are not readily available.