Convenience is a central factor in medication compliance. The easier a treatment is to self-administer, the more likely it is that a patient will stick with a prescribed therapy. To that end, pharmaceutical companies are working to come up with drug delivery methods that maximize convenience and ease of use. Transdermal patches, or medicated adhesive patches that deliver medication through the skin, and topical treatments may deliver on this front.
Administering medication transdermally offers several advantages over other methods of drug delivery. Patches, gels, sprays and creams are convenient and easy to apply. Because the medication bypasses the digestive system, it may be easier on patients who experience gastrointestinal upset from certain oral medications. They offer improved mobility by freeing patients from pumps and other medical devices. Finally, they can improve compliance in patients who might forget or otherwise not bother to take their pills.
Transdermal patches provide continuous, controlled drug delivery directly to the bloodstream, allowing for improved bioavailability. They are already well-known for their use in contraceptives, pain relievers and smoking cessation aids, but they can be used for other applications as well. Transdermal patches to treat dementia, attention-deficit/hyperactivity disorder, knee osteoarthritis, overactive bladder, menopause, diabetes, hypertension and Parkinson’s disease are already on the market.
The most commonly reported side effect of transdermal patches is skin irritation. Getting the drug through the skin is another challenge, since the skin is designed to be a protective barrier. Products may rely on the techniques of iontophoresis or sonophoresis, which use a low-grade electrical current or ultrasound, respectively, to deliver a drug through the skin. Alternately, patches may utilize micro-needles, or tiny needles that open up pores to let the drug through. Companies that work with transdermal patches include Aveva Drug Delivery Systems and Noven Pharmaceuticals. Two transdermal medications currently in the pipeline: NuPathe’s migraine patch and Pantec Biosolutions’ triptorelin hormone patch.
For patients who experience skin irritation from patches, topical treatments offer transdermal drug delivery minus the patch. One example of a transdermal product is BioSante Pharmaceuticals’ LibiGel, a testosterone gel to treat female sexual dysfunction. According to Stephen M. Simes, President and CEO of BioSante, transdermal products such as LibiGel can deliver medications that cannot be taken by mouth because they break down in the stomach or liver. Although some manufacturers work around this problem by increasing the dose of the drug, testosterone and certain other treatments cannot be delivered orally no matter how high the dose.
Simes says that transdermal drug delivery has the potential to increase patient compliance. “There are some people who can’t take pills because they cause stomach upset or they can’t remember to take the pill, so transdermal might become more a part of their daily routine,” he says. Since testosterone cannot be taken orally, Simes believes that compliance will be assured with LibiGel. The product is currently undergoing a Phase III clinical trial to track serious cardiovascular and breast cancer events. If approved, LibiGel would be the first product on the market to treat female sexual dysfunction.
Other companies that offer patchless transdermal drug delivery include TransDermal Technologies, Piedmont Pharmaceuticals and ASCEND Therapeutics. What are some other drug delivery technologies that have the potential to improve convenience and adherence?
