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A promising novel drug delivery system, oral thin films (OTFs), are intended to deliver active therapeutic moieties either locally or systemically in the oral cavity under the tongue, on the roof of the mouth, in the intestines, or while held in the mouth.

Fast or sustained release of the active substance are enabled by oral thin film technologies, ensuring the ideal dosage is delivered to the target location within the body. While this novel drug delivery system may not yet be widely used, it offers multiple benefits to both the patient and the manufacturer, and some believe that oral thin film delivery systems may be used more prevalently in the near future.

Types of oral thin films

Two principal forms of oral films, oromucosal films, and orodispersible films, are defined in greater detail below, as well as in Figure 1.

Oromucosal films

Oromucosal films are mucoadhesive and are designed to deliver components either locally or systemically. Sub-categories of oromucosal films include buccal films, sublingual films, and palatal films, which vary, as they are dependent upon the site of application and/or route of absorption.

Orodispersible films

Orodispersible films are primarily non-mucoadhesive, disintegrating in the mouth when they come into contact with saliva. As such, orodispersible films do not require the use of water or chewing. Depending on the ability of the orodispersible film to on their disintegrate or dissolve in the mouth, they are classified as either orally disintegrating or orally dissolving.

Figure 1. Two subtypes of oral thin films, oromucosal and orodispersible

The makeup of oral thin films

Oral film formulations may include, but are not limited to:

• Polymers
• Plasticizers
• Viscosity enhancers
• Disintegrants
• Stabilizers
• Surfactants
• Other additives (e.g., sweetening agents, saliva stimulants, coloring agents, etc.)

The two key components of oral thin film formulations are polymers and plasticizers. Material selection is critical, as hardness, disintegration, dissolution properties, and overall performance of the film are greatly impacted by the materials used within the formulation. The OTF must function properly, pose no threat to patient acceptability, and the mechanical properties must facilitate ease of manufacturing.

Needed improvements in oral thin film drug delivery

Every drug delivery system has both advantages and challenges. While OTFs have many positive qualities, which will be discussed, room for improvement remains. One of the challenges facing oral thin film delivery systems is packaging and dosing limitations, as OTFs are better suited for small dose drugs. With more research and optimization of this novel drug delivery system, oral thin film delivery systems will likely be able to be utilized for a wider range of active pharmaceutical ingredients (APIs) and drugs. Additionally, there is limited regulatory guidance available regarding the development and testing of oral thin films, which presents further challenges for researchers and drug developers.

Advantages of the oral thin film drug delivery system

As previously stated, oral thin film drug delivery systems offer many advantages. OTFs can be a lifesaver for specific patient populations, including pediatric patients, geriatric patients, and patients who have difficulty swallowing solids or liquids. Furthermore, OTFs enable accurate dosing, provide ease of transport, and due to their ease of use, will help to reduce instances of medication non-adherence. OTFs are easily accessible and can be manufactured for larger surface areas with faster wetting, disintegration, and dissolution.

When compared to the process for manufacturing tablets and capsules, manufacturing OTFs is simpler and faster, as there are fewer processing and manufacturing steps. Moreover, studies have been conducted which address the possibility of incorporating poorly water-soluble films into oral films. There are many who believe that the oral film platform technology will soon be the novel drug delivery system of choice, particularly for geriatric and pediatric patient populations.