Adhesive-based delivery systems provide controlled, reliable drug administration, frequently improving bioavailability and reducing dosing frequency. For sponsors, this means better pharmacokinetic outcomes and safer treatments. To develop a successful, patient-ready product, however, a deep understanding of the key qualities, components, and dosage forms is essential.

Adhesives bond surfaces together, creating stable, durable connections. Composed of either natural or synthetic polymers, these materials are engineered to deliver specific properties such as flexibility, strength, and resistance to environmental factors. Over time, adhesive technology has advanced from simple glues to highly specialized materials across healthcare and pharmaceuticals.

In medicine, adhesive coatings go beyond bandages and medical devices—they are engineered to facilitate drug delivery. By regulating absorption rates, these adhesives ensure active pharmaceutical ingredients (APIs) efficiently reach their intended target. As demand for non-invasive, controlled-release therapies climbs, adhesive systems like transdermal and topical patches provide the perfect solution. They offer consistent dosing, improved pharmacokinetics, and minimized risk of adverse events for enhanced therapeutic outcomes and patient compliance.

In this blog, we’ll highlight the key points sponsors should know about adhesives, including:

• The History of Adhesives in Drug Delivery
• Qualities and Components of Effective Adhesive Delivery Systems
• Types of Adhesive-Based Drug Delivery Dosage Forms

The History of Adhesives in Drug Delivery

Early Uses of Adhesives in Medicine

The use of adhesives in medicine dates back centuries, with early civilizations relying on naturally derived substances to close wounds, secure bandages, and even deliver basic treatments. 

Ancient Egyptians, for example, used honey and tree resins for their antimicrobial and adhesive properties in wound care, while the Greeks and Romans applied plant-based glues to hold dressings in place. These early applications, though rudimentary, highlighted adhesives’ critical role in medical treatment.

As medical practices advanced, so did the materials used for adhesion. In the 19th century, the development of rubber-based adhesives marked a significant breakthrough, with the first surgical tape made from a combination of India rubber and other natural substances. This innovation improved the reliability of medical tapes and wound dressings. By the early 20th century, further refinements led to the invention of the Band-Aid®, combining gauze with adhesive tape to create a more practical and effective solution for wound care.

Breaking into Drug Delivery

Adhesive technology began to revolutionize drug delivery in the mid-to-late 20th century when researchers realized the potential of adhesive systems for controlled drug release. Advances in synthetic polymers and pressure-sensitive adhesives (PSAs) made it possible to develop transdermal patches and topical adhesive-based delivery systems.

READ MORE: Transdermal Patches: What They Are, How They Work & Why Patients Like Them

A key development came with the rise of medical-grade adhesives, pioneered by companies like Adhesives Research. Throughout the 1980s and 1990s, innovations in pressure-sensitive adhesives and polymer coatings paved the way for transdermal and topical systems that offered controlled release of active ingredients. This progress was instrumental in the creation of treatments such as nicotine patches for smoking cessation, hormone replacement therapies for postmenopausal conditions and contraception, nitroglycerin patches for the treatment of angina, and pain relief systems. 

One landmark moment was the approval of the Transderm-Scop® patch for motion sickness in 1979, the first transdermal patch for motion sickness. Using an adhesive matrix, this patch delivered scopolamine through the skin over three days, demonstrating the viability of adhesive-based drug delivery and fueling further breakthroughs. Over the years, the development of adhesive technologies has focused on enhancing drug permeability, wear time, and patient comfort—improving the practicality of these systems for widespread use.

Today, advancements in bioadhesives, hydrogel-based adhesives, and polymer formulations push the boundaries of drug delivery. These innovations allow for controlled and extended drug release with minimal patient intervention, improving treatment efficacy and patient adherence by offering noninvasive, convenient alternatives to traditional medication dosage forms.

The Future of Adhesives in Drug Delivery

Advancements in adhesive technology are shaping the future of drug delivery, with innovations in bioadhesives and polymer coatings improving drug absorption and pharmacokinetics while reducing adverse events. 

Bioadhesives enhance biocompatibility, allowing for better adhesion to biological tissues and more efficient drug absorption and release. Polymer coatings are evolving to provide more precise, extended-release control, reducing dosing frequency and improving patient compliance. 

These developments help maintain consistent drug absorption, uniform drug blood levels, minimizing side effects, particularly for chronic conditions requiring long-term management. Moving forward, sponsors can expect even more adaptive systems that respond to physiological changes—like body temperature or blood glucose levels—for greater precision in drug delivery.

Qualities and Components of Effective Adhesive Delivery Systems

The success of adhesive-based drug delivery systems depends on several key properties. Here are the essential characteristics that make an effective patch system:

Core Properties of Medical Adhesives

Adhesion Strength

Adhesion strength is critical to ensure the patch stays in place throughout its intended wear time. If the adhesive is too weak, the patch may lift or peel off, leading to inconsistent drug absorption. If the adhesive is too strong, removal can cause pain and skin irritation or damage. 

The ideal adhesive provides long-lasting yet gentle adhesion, even under challenging conditions like sweating, bathing or friction. Pressure-sensitive adhesives (PSAs) are commonly used in transdermal patches for secure, effortless application.

Biocompatibility

Since these systems remain in direct contact with skin or mucosal tissues for extended periods, biocompatibility is essential. The adhesive must be non-toxic, hypoallergenic, and free from irritants to prevent adverse reactions from the inactive components. 

Regulatory standards from the FDA and ISO 10993 ensure adhesives are safe for use, especially for sensitive skin.

Flexibility and Conformability

For the adhesive system to remain effective, it must move with the skin without losing adhesion or causing discomfort. Skin constantly stretches and shifts, and a rigid patch may detach prematurely. In development, look for visco-elastomeric polymers designed to stretch and adapt to the skin’s movement, even on curved, high-motion, or delicate surfaces of the body.

Controlled Drug Release

Adhesives do more than just stick—they actively control how medication is released into the body. The adhesive matrix may be designed to regulate drug diffusion, ensuring a consistent, predictable dose over time. Key methods of regulating drug diffusion include:

• Reservoir Systems: A liquid or gel drug formulation in a reservoir is released through a rate-controlling membrane.
• Matrix Systems: The drug is embedded within the adhesive itself, diffusing directly into the skin upon contact. Rate-controlling membranes may be utilized in combination with multiple matrix layers.
• Multipolymer Blends: Combining different adhesive chemistries to fine-tune drug release and maximize bioavailability while preventing sudden drug release.

Components of an Adhesive Drug Delivery System

Adhesive drug delivery systems are meticulously designed to ensure secure application, controlled release, and optimal patient comfort. Each component plays a crucial role in the system’s effectiveness, whether in transdermal, topical or buccal thin films.

Drug Reservoir

In a transdermal patch, the drug reservoir holds the active pharmaceutical ingredient (API) in forms like gels, solutions, or semi-solid or solid matrices. Drug release is regulated by the reservoir, either through direct diffusion or via a rate-controlling membrane, allowing for a controlled and sustained release over time.

Adhesive Layer

The adhesive layer in transdermal patches ensures the patch stays securely in place and facilitates drug diffusion into the skin. Advanced adhesives in these systems are designed for both long-term and short-term wear, providing adequate adhesion without skin irritation. Some adhesives also contain skin-conditioning agents to improve comfort, especially for patients with sensitive skin.

Backing Layer

The backing layer serves as the outermost protective barrier of the patch, offering structural support and resistance to moisture, friction, and rapid temperature changes. Depending on the therapeutic goal, it can be occlusive (to promote drug absorption) or non-occlusive (to allow skin breathability). Occlusive backings are commonly used in transdermal patches to enhance drug permeation through the skin.

READ MORE: Transdermal Administration Routes for Drug Delivery: A Short Guide

Release Liner

The release liner protects the adhesive layer and drug reservoir until the patch is ready for use. It is removed before application, ensuring that the active ingredients remain intact until the patch is applied to the skin. Specialized liners may be used to protect sensitive APIs from light, moisture, or air.

Buccal Patch Components

Mucoadhesive Polymers

Mucoadhesive polymers help the film adhere to the wet buccal mucosa surface. Combining different mucoadhesive polymers helps balance drug release, improve the film’s mechanical properties, and increase flexibility. Adjusting polymer rations lets manufacturers control drug diffusion rates.

Drug Matrix

The drug matrix holds the active pharmaceutical ingredient (API) and can be in solid or semi-solid form. The matrix controls how the drug is released:

• Immediate Release: Hydrophilic polymers release the drug quickly when they absorb water.
• Directed Release: Hydrophobic polymers slow down release for a longer duration.

Plasticizers

Plasticizers improve the flexibility and durability of the mucoadhesive, or the drug matrix, or both layers. They make the dosage form stronger, more elastic, and more comfortable to wear, allowing it to flex within the mouth.

Backing Layer

The backing layer gives the film structure and protects it from saliva and physical damage. It may be designed to dissolve over time or remain intact for easy removal, depending on the product’s needs.

Release Liner

The release liner is a protective layer that is removed before the buccal patch is applied. It keeps the patch intact, preventing contamination and protecting sensitive APIs from diffusing into the packaging during storage.

Types of Adhesive-Based Drug Delivery Dosage Forms

Transdermal Patches

Transdermal patches are one of the most widely used adhesive drug delivery systems. They deliver medication directly through the skin into the bloodstream, bypassing the digestive system and reducing first-pass metabolism. This method enables sustained drug release over hours or even days.

There are various types of transdermal patches, each designed for specific therapeutic needs:

• Single-layer patches incorporate the drug into the adhesive, providing a steady release. These are typically used for medications that require lower doses over time, such as nicotine replacement or mild pain relief.
• Multi-layer patches allow for controlled drug release in stages, ensuring gradual absorption. This makes them well-suited for medications, such as cardiovascular drugs, that require a sustained effect.
• Reservoir patches provide precise dosing through a rate-controlling membrane, commonly used for hormone replacement therapies and chronic pain management. 
• Matrix patches, with the drug incorporated into a polymer matrix, provide steady, sustained release and are versatile for long-term therapies like pain management and hormone replacement.

Topical Patches

Unlike transdermal patches, which deliver drugs systemically, topical patches focus on localized treatment. These include adhesive bandages infused with active ingredients, medicated gels, and hydrocolloid patches used in dermatology and wound care. The adhesive component helps maintain consistent contact with the skin, improving drug absorption and prolonging therapeutic effects.

Recent innovations in topical drug delivery focus on enhancing localized absorption and efficacy. Advances include lipid-based nanocarriers that improve drug penetration into the skin without systemic absorption and bioadhesive formulations that prolong contact time for sustained therapeutic effects. These breakthroughs are shaping precision medicine in dermatology and pain management.

Buccal Patches

Buccal patches are an effective adhesive-based drug delivery form designed for localized treatment in the mouth or for systemic delivery of drugs. These patches adhere to the buccal mucosa and can be designed to deliver medication directly into the bloodstream through the tissues in the mouth, bypassing the digestive system. Buccal patches can provide topical delivery of drugs to areas of the oral cavity in need of treatment for pain or other medical conditions.

Buccal patches are increasingly popular for drugs that need rapid onset of action, such as pain relievers, anti-nausea medications, and anxiety treatments. They offer benefits like ease of use, discreet application, and rapid absorption. However, buccal patches are limited by the drug volume they can deliver and the sensitivity of the mucosal surface to the active ingredient.

Conclusion

Adhesive-based drug delivery systems offer a versatile, controlled, and patient-friendly approach to medication administration. Whether through transdermal patches, topical applications, or other technologies, these systems enhance drug efficacy and compliance. 

Partnering with an experienced provider specializing in adhesive formulations, like ARx (formerly Adhesives Research), can help ensure the successful development of innovative drug delivery solutions.

ARx is a patient-friendly, novel drug delivery partner. We specialize in transmucosal and transdermal patch strategies — all backed by tailored, full-scale development services. Contact us today to find the right delivery system for your API.