Transdermal patches are a rapidly growing market. More companies are choosing skin patches as a reliable delivery system, and more consumers are looking for an easy, non-invasive way to take their medications.
However, the science of making a drug formulation is vastly different than the science of making an effective transdermal patch. That’s where working with an experienced manufacturing partner with materials expertise can set your product up for success.
In this article, we’ll discuss important materials considerations when designing and producing transdermal patches.
Advantages of transdermal patches
Transdermal patches are topical medications or products. The patch attaches to the patient’s skin thanks to skin-friendly adhesive. The active formulation then absorbs through the skin and enters the bloodstream.
Compared to other drug delivery methods such as oral and intravenous, transdermal patches offer several benefits that improve the drug’s efficacy and patient compliance.
- Non-invasive, easy, and painless application
- Controlled and consistent therapeutic dosage (no peak dose effect)
- Avoids first-pass effect, where the drug is metabolized before systemic circulation
Based on these benefits, transdermal patches have become an increasingly popular delivery method for both pharmaceuticals (such as nicotine, fentanyl, buprenorphine, and more) and nutraceuticals for OTC or recreational use (including CBD, caffeine, Vitamin B12, etc.).
Layers and materials of transdermal patches
There are several common designs of transdermal patches, including drug-in-adhesive (DIA), classic reservoir, polymer matrix, and multi-laminate solid-state reservoir. The following are layers commonly found in transdermal patches and material considerations for each layer.
Drug formulation
Let’s start with the drug formulation layer, which is the medication or supplement compound of a transdermal patch that absorbs into the skin. The formulation can take several forms:
- The classic reservoir design places the drug formulation between the backing and membrane layers
- If multiple drugs are needed at different doses or diffusion rates, formulations are separated by an extra membrane layer
- With drug-in-adhesive patches, the dry powder of the drug is mixed in with the adhesive
- Another method for placing the drug directly on the skin is with a polymer matrix reservoir
The type and quantity of drug formulations will help determine the other layers of the transdermal patch.
Backing
The purpose of the backing is to protect the integrity of the patch. The material is sealed to the membrane layer, essentially creating a pouch around the drug formula layer. The backing can also be printed on for branding or product information.
When choosing a backing material, we recommend considering patient comfort, stability, and cosmetic appearance.
Membrane
A membrane is often used in multi-layer or reservoir transdermal patches. The membrane controls the diffusion rate of the drug formula into the skin. When selecting materials for transdermal patch membrane, characteristics to look for include flexibility, thickness, permeability, ability to be directly laminated to adhesives, history of use, and more.
Skin tapes and adhesive
Due to the challenging and sensitive nature of sticking to skin, the adhesive or tape layer of a transdermal patch is crucial. Skin-friendly tapes provide reliable adhesion and are biocompatible to prevent discomfort or harm to the user. Sometimes these are called medical tapes or medical-grade adhesives.
Release liner
The release liner’s job is to protect the adhesive (and, in some applications, the drug formulation) until the transdermal patch is ready to be applied to the user. It’s crucial that the release liner is easy to peel off and that the release is consistent from lot-to-lot and for the product's life. Release liner materials can be compatible with several skin-friendly adhesives, including silicone, acrylate, and polyisobutylene (PIB). For DIA transdermal patches, the release liner should not have any interactions with the drug formulation.
What to look for in a transdermal patch manufacturing partner
With the exception of the drug formulation, transdermal patches are made by custom converting raw materials and combining the layers. An experienced manufacturing partner can provide immense value, especially for pharmaceutical companies or product designers focused on developing the drug formulation. When selecting a manufacturing partner, ask about the company’s material and design expertise, regulatory experience, and manufacturing capabilities.
At Tapecon, we offer a full range of custom converting and printing services. Our facility is ISO 13485 certified and FDA Registered, with clean room converting capabilities.
Let’s make something great
With over 100 years of manufacturing experience, Tapecon works with product teams to solve challenges, create products, and enhance lives. Learn more about our wearable skin tapes and patches capabilities.
