A transdermal drug delivery system (TDDS), or adhering dermal patch, is a medication delivery system that delivers a specific, controlled dose of a therapeutic drug across the skin and into the bloodstream.
Transdermal patch delivery systems have seen a slow but steady rise in prescription market share over the past 30 years. Drug manufacturers continue to progress the availability of dermal adhesive patch formulas to meet the demand for this safe, convenient, effective, and still emerging mode of drug administration. The transdermal drug patch market is expected to grow at a compound annual growth rate (CAGR) of 4.5% until 2023.
This continued market growth of transdermal adhesive patches is reflective of the many benefits associated with its form and function, including:
Drug properties must be considered when selecting an adhesive for a transdermal delivery patch. Currently, there is limited availability of commonly used medications in transdermal formulations. Drugs that require relatively consistent plasma levels are good candidates for transdermal drug delivery.
Drug delivery, rate, flux, physical integrity of the finished product, skin maceration, and chemical stability are all variables that influence the transdermal transport and bioavailability of the API through the structural layers of the skin.
Skin adhesion is a critical measure in the design and manufacturing of transdermal patches in order to achieve intended drug delivery to the patient. Many available transdermal patches are meant to be removed within 24 hours of dermal application. However, new formulations have been designed for longer wear times of even up to seven continuous days.
Skin integrity and dermal adherence quality of the patch are dependent on age, race, and patient health which contribute to overall skin variations. Likewise, variations of skin surface energy and skin stretching at different body locations affect transdermal patch wear and performance. These factors must be considered by an adhesives expert in order to achieve a consistent delivery profile across a varied patient population.
Human skin creates a highly protective barrier. Skin biocompatibility is a major concern in dermal applications. Skin adhesives must be designed to include a biocompatible adhesive delivery system to prevent skin irritation.
An additional consideration in the formulation of a dermal adhesive patch is dependent upon its impact on skin, breathability, and adhesion efficacy—all of which are vital to the performance, efficacy, and safety of the system.
With the correct adhesive, patch design, and care in API selection, the benefits of intravenous infusion can be closely duplicated by using skin as the system of entry. Patient compliance and continuity of care in drug administration are critical in improved patient health. Continued development and improvement of current TDD system adhesives allow a patient to better maintain steady drug levels and eliminate injections. These benefits and an improved side effect profile remove common barriers to drug administration. This ultimately improves patient compliance and outcomes.
As our current healthcare system undergoes change, there is a growing trend to popular patient-administered treatments via remote care settings. Continued improvements in adhesives will pave the way for future applications of transdermal dermal drug delivery patches that will help meet the increased demands of the new virtual and remote healthcare model.