The emerging nutrition delivery system: Oral thin Films (OTFs)

This nutrition delivery system is becoming more popular as the science behind OTF design advances. There is a predicted increase in OTF market valuation and many companies fully comprehend the benefits of this form of nutrition intake. Many pharmaceutical companies are transitioning from tablets to fast-acting oral thin films (OTFs).

Oral thin films combine the benefits of tablets (precise dose, ease of administration) and liquid dosage forms (easy swallowing, rapid bioavailability). According to statistics, four out of every five patients prefer orally disintegrating to traditional solid oral dosage forms.

Evolution of Oral films:

Thin film is not a new formulation; it was first introduced in late 1970 to address swallowing issues associated with tablets and capsules. The oral film, oral soluble film, wafer, oral strip, orodispersible film, buccal film, mucoadhesive film, and other types of thin films have appeared.

While some films are designed to dissolve quickly in the oral cavity to allow quick absorption in the gastrointestinal cavity, others are prepared to deliver the dose at the administration site (e.g., buccal, sublingual, and ophthalmic thin films). 

Strips with high mucosal permeability have previously been shown to be suitable for buccal and sublingual film delivery. Similarly, ophthalmic, oral thin films are commonly used to treat anterior segment diseases such as conjunctivitis, glaucoma, and chronic dry eye syndromes.


The criteria for OTF formulation differ significantly from those for tablets and capsules. OTF formulation has more constraints than tablet and capsule formulation. Tablets and capsules can be solid or gelatinous, large or small. They can also contain additives that improve stability and solubility.

OTF formulation must be designed to understand that the end product will be a small polymeric film. OTFs necessitate special considerations for film dimension and thickness, viscosity, flexibility, and tensile strength. In addition to basic physical properties, formulation decisions for OTFs are tailored to the strip’s physicochemical properties, the amount of medication required, and the desired OTF release type.

Benefits over traditional dosage forms

The oral thin films dissolve more quickly than other common dosage forms. Thin films are less brittle and easier to transport than commercialized orally fast disintegrating tablets, which require special packaging. Similarly, a single dose of the strip can be carried without a secondary container. It is critical to address the poor stability of liquid dosage forms, particularly aqueous formulations. In contrast to thin films, excellent care is needed during accurate measurement of the amount. Shaking the bottle every time before administration may contribute to less patient acceptance.

Misconceptions about oral films:

The distinction between disintegration and dissolution is one of the most common misconceptions about OTFs. Dissolution happens when a strip dissolve (for example, in saliva), whereas disintegration occurs when a film breaks up into pieces that disperse in the oral cavity for easier swallowing.

Another common misconception is that oral thin films can only transport nutritive supplements that are soluble in water. These tend to disintegrate and dissolve in the oral cavity simultaneously. Thus, the strip’s solubility determines its performance, including where it is absorbed.

Traditional ophthalmic nutrition delivery systems, such as eye drops or solutions, are widely used, but their ability to provide high ocular bioavailability and sustained duration of action is limited. To improve this, ophthalmic thin films can be used. As opposed to the transdermal patch, the transdermal film is associated with minor skin irritation due to less occlusive properties that improve water vapor permeation through the skin and do not leave a sticky sensation at the site of application.

Also Read – The Utility of Mouth Dissolving Strips

Advantages of oral thin films;

  • The final form of OTFs allows for rapid production. Manufacturers can produce them around the clock with the development of powderless, aqueous-based film manufacturing that does not require solvents. 
  • This process is efficient because it only requires two steps of mixing followed by casting, whereas manufacturing tablets and capsules is far more complicated. OTFs are ideal for drugs in development whose production has not yet begun to include large doses due to their capacity to carry a small load. 
  • Even poorly soluble biochemicals can be incorporated into OTFs, increasing their utility, but the main benefit of OTFs is that they are incredibly patient-friendly. 
  • Because OTFs have a much larger surface area than other nutrition delivery methods, they wet, disintegrate, and dissolve much faster. 
  • To administer oral thin films, no water, chewing, or swallowing is required; saliva is sufficient to disperse.
  • OTFs can also be designed with pleasing colours and Flavors to appeal to young children. Furthermore, those receiving medication through OTF will find the films convenient to transport and handle.
  • OTFs are a type of “precision medication,” with perforations in a single film that provide dosing accuracy and flexibility. Because children require smaller doses, dosing flexibility is ideal for paediatric applications.

Polymers used in the fabrication of oral thin films

Polymers are the foundation of film formulations, and there are numerous polymers available to prepare thin films.

The polymers can be used alone or in combination with other polymers to achieve the desired film properties. The polymers must be non-toxic, non-irritating, and free of leachable impurities. Water-soluble polymers are used as film formers to create a thin film with rapid disintegration, high mechanical strength, and a pleasant mouthfeel. For film preparation, both natural and synthetic polymers are used.

The availability of various polymers allows for the imparting of specific properties in thin films. For example, gelatines are available in multiple molecular weights, and thus appealing and glossy films could be produced using gelatine with a high molecular weight. Pullulan is frequently used to create thin films with high mechanical strength and solubility over a wide temperature range.

The bottom line:

A film must have adequate flexibility, softness, elasticity, and Physico-chemical stability to be considered an ideal thin film. As a result, all of these parameters should be carefully considered while developing film to ensure its efficient performance. 

A pre-requisite is the characterization of oral thin films, which may include assessing properties such as mechanical strength, hydration, in vitro release, and surface morphology. The above section follows the various critical quality attributes that affect film properties and the most commonly used in vitro methods for film characterization.