Overview of FDA guidelines for transdermal patches in the US with AdhexPharma, your CDMO partner

Transdermal patches represent a true revolution in drug administration. Applied to the skin, they deliver the active ingredients in a controlled and sustained manner into the bloodstream through the skin. This route of administration avoids the hepatic first-pass effect associated with oral delivery, as well as the need for injectable routes. It offers numerous benefits: precise dosing, continuous delivery, improved compliance, discreet use for the patient, as well as many prospects for the future.

The transdermal patch market in the United States is experiencing dynamic growth and is expected to reach nearly 11 billion dollars by 2029 [1]. This is explained by the high prevalence of chronic diseases, the growing demand for innovative solutions, and the existence of an advanced healthcare system.

However, accessing this market means meeting strict regulatory requirements: the FDA (Food and Drug Administration) requires a high level of quality, safety, and efficacy for every marketed patch, like in Europe [2].

FDA Regulation:
In the United States, the FDA considers transdermal patches as combination products (products combining a drug and a medical device). This means that they must meet the regulatory requirements for both drugs and medical devices. In fact, marketing a transdermal patch in the United States involves complying with a particularly demanding regulatory framework, which aims to guarantee the safety, efficacy, and quality of the product at every stage of its lifecycle.

The development of a transdermal patch begins with a thorough understanding of the medical needs to be addressed: what dose to deliver, for how long, and for what type of patient? Each component of the patch — active ingredient, adhesives, release liner and backing — must be chosen to ensure the stability of the drug, compatibility with the skin, and the overall performance of the system. Special care is taken in selecting the materials in contact with the skin, which must be biocompatible and non-irritating.

In this logic of rigor, the FDA requires that the entire development process be meticulously documented and validated. This includes justification for the choice of excipients, evaluation of the impact of penetration enhancers, the solubility of the active ingredient in the matrix, as well as the patch’s ability to deliver a precise and constant dose of medication.

Transdermal patches must meet particularly strict quality criteria, assessed using specific analytical tests: uniformity of the active ingredient content, release rate, adhesive strength, absence of physical defects, as well as stability under varied conditions (temperature, humidity, light). Biocompatibility studies are also necessary to ensure that the patch does not cause irritation or skin sensitization.

The FDA also requires the validation of every step of the manufacturing process, from mixing the components to final assembly, in order to guarantee the reproducibility, quality, and safety of the finished product.

The performance of the patch must then be confirmed under real use conditions. It must remain effectively adhered to the skin for the entire duration of application, and continue to deliver the active ingredient reliably, even in cases of heat, sweating, or humidity.

The marketing authorization holder must also anticipate the risks of incorrect use and provide clear, readable, and accessible instructions on the patient leaflet to ensure safe and optimal use by patients.

In summary, to obtain marketing authorizations, it is essential to submit to the FDA a complete dossier detailing the design of the patch, the results of safety and efficacy studies, quality control methods, stability data, as well as manufacturing and risk management procedures. The traceability of each batch and the ability to react quickly in the event of a safety incident are also among the key requirements of the American regulatory framework.

Our expertise at the service of your transdermal projects:
At AdhexPharma, we support pharmaceutical laboratories throughout the development of their transdermal patches, from design to industrial manufacturing. With solid experience in this field, we master the American regulatory requirements.

We help you choose suitable materials, ensure the quality and safety of your products, and structure the necessary documentation to meet the authorities’ expectations. Our GMP-certified facilities and dedicated technical teams ensure reliable, traceable production that complies with the strictest standards.

Our team is at your disposal to study your needs and build, with you, tailor-made transdermal solutions, ready to meet the requirements of the American market. Do not hesitate to contact us to discuss your project and discover how AdhexPharma can support you at every stage.

References:

[1] Transdermal Skin Patches Market Size | Mordor Intelligence. Accessed: June 17, 2025. [Online]. Available at: https://www.mordorintelligence.com/fr/industry-reports/transdermal-skin-patches-market

[2] Center for Drug Evaluation and Research, "Transdermal and Topical Delivery Systems – Product Development and Quality Considerations." Accessed: June 17, 2025. [Online]. Available at: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/transdermal-and-topical-delivery-systems-product-development-and-quality-considerations