Go Deeper: Compounding for Topical and Transdermal Drug Delivery
Much of the work of compounding pharmacists involves topical and transdermal delivery systems. But what is the difference, and how are they best used? As someone who was offered topical alternatives for pain management after an injury, I discovered that I didn’t fully understand these issues. Patients need to know the reasons behind topical and transdermal drug delivery systems and how they can benefit from these differing methods to make the most informed choices about their care.
Comparing Transdermal and Topical Delivery
Although many use the terms transdermal and topical interchangeably, these delivery methods for medications are distinct, and their differences are significant. Topical medications are designed to impact only the application site. They do not allow high concentrations of the drug into the tissues or bloodstream making them ideal for targeted use and trigger fewer adverse reactions. Examples of commonly used topical medications include corticosteroids to fight skin irritation, anesthetics like lidocaine and certain antibiotics such as over-the-counter Bacitracin.
Transdermal drug delivery systems, on the other hand, are designed to impact the entire body. Transdermal medications will absorb into the bloodstream and bodily tissues through mucosal membranes or the skin. Like injectable and oral medications, they are used to treat systemic issues and impact areas of the body distant from where you apply the medication. Transdermal drug delivery systems are especially important for patients that cannot swallow, treatment of problems related to the digestive system such as nausea, and for use with medications that have substantial impact on the liver. Transdermal drug delivery systems are a frequent choice for hormone replacement therapy, anti-nausea prescriptions, and systemic pain management.
What makes the application of one drug to the skin topical and another transdermal? Or, in other words, how is it determined whether a drug applied to the skin will have a local, regional or a systemic effect? Several factors determine the extent of the drug’s effect including the kind of preparation, its concentration, the solubility of the medication, and the size of active drug molecules all control the outcome.
Topical or Transdermal Drug Delivery Systems: Which Make Sense?
Some medications have undesirable side effects. Many pain relief medications, for example, cause drowsiness; this is also true of some anti-inflammation medications and muscle relaxers. Side effects are especially problematic for athletes and those with professional obligations. Topical application of medication can provide much of the needed therapeutic effects while substantially lowering the incidence of adverse effects.
Muscle relaxers and anti-inflammatory treatments such as ketoprofen, applied topically, can be very effective. With topical application of these kinds of drugs, the concentration of the medication will be very high locally while greatly lessening the systemic presence. Therefore, the muscles or joints in question are more impacted while the rest of the body isn’t, significantly reducing the chances of bleeding or upset in the gastrointestinal system.
The proper compounding of topical medications like these is critical. Ketoprofen at the proper compound concentration and applied topically can have an impact at the site that is 100 times greater than the overall concentration throughout the body. This maximizes pain and inflammation control while minimizing gastric upset and sleepiness.
For those drugs that the patient’s entire body needs such as hormone replacement, nitroglycerin therapy for heart disease or pain management for cancer or systemic pain patients, transdermal delivery systems are ideal. Hormones are more effective when they bypass the gastrointestinal system (as they do when the body produces the hormones itself). And pain management meds that avoid the GI tract have more impact with fewer negative side effects.
Compounding the precise medication to treat an ailment is both a science and art. Achieving the very best result is the overriding goal. The savvy use of topical and transdermal delivery systems helps healthcare providers treat the needs of every single patient, no matter how unusually they might present – an incredible advantage achieved through compounding.
Compounding topical and transdermal medications for patients is a key service area that requires the highest quality ingredients and the best, most current information. Pharmaceutica North America wants to be your resource for high-quality compounding products and information. For more about pharmaceutical compounding and purchasing bulk APIs, please contact Pharmaceutica North America, your trusted compounding resource.