A number of technologies are available that allow hydrophilic drugs to be absorbed through the skin rather than the GI tract. Transdermal delivery through the skin has a number of advantages over oral delivery, including better absorption, greater flexibility in how the drugs are administered and more choices for patients in how they receive their medication.
Delivery of hydrophilic drugs through a transdermal patch presents a solution to many of the problems currently associated with other delivery methods for hydrophilic drugs, most notably, by avoiding all GI tract issues and by improving patient compliance compared with oral delivery. This is because there are no restrictions around the time that the drug should be administered or whether the patient may eat afterward. In particular, multi-day patch delivery offers ease of use and is convenient, without the requirement to remember to take a drug at a specific time. There is also the advantage of increased bioavailability, which means that smaller doses may be used for the same drug, helping to minimize side effects. Third, the problem of first-pass metabolism is avoided, as well as the peaks and valleys created by GI tract absorption. Dosage may be stopped abruptly by removing the patch if adverse side effects are experienced. Transdermal delivery promises to radically increase the effectiveness in which hydrophilic drugs are administered by reducing the need for injection as well as decreasing the dosage required by bypassing the GI tract.
Nicotine patches are a widely used transdermal drug delivery system. Their size depends on the dosage and brand used, but generally is between one and two inches square. The patch provides a steady, controlled dose of drug throughout the day, reducing the effects of withdrawal. Patch strength can be reduced over time, allowing users to wean themselves off of an addiction gradually. There are many drugs that can be delivered by skin patch including oestrogen, progesterone and testosterone.
The present invention proposes an improvement to the skin patch delivery system. A metal ring has a symmetrical groove machined all the way around its inside surface. The groove contains an open pore capillary medium that "wicks" the drug to be dispensed. This wick is connected to a reservoir on the top of the ring that holds the liquid drug. Fluid pressure in the reservoir can be adjusted by a set screw, controlling the rate at which the drug is dispensed to the capillary medium.
Advantages of this innovation include:
•Infinitely reusable and produces no medical waste to go to landfill. A patch is thrown away after each use.
•Rate of drug delivery and drug concentration can be finely adjusted during treatment to match the needs of the patient
•System is invisible leading to a better cosmetic result