Sigma institute of Pharmacy, Sigma University, Bakrol, Vadodara-390019
Fast-dissolving film is an accurate and accepted oral dosage form that bypasses the hepatic system and results in a therapeutic response. It is preferred by pharmaceutical industries for its acceptance by both industry and patients, especially among pediatric and elderly patients. This dosage form is cost-effective and meets consumer demand, which allows it to be used as a replacement for over-the-counter (OTC), generic, and brand-name medications. When placed in the oral cavity, fast-dissolving film immediately absorbs moisture, adheres to the application site, and then break down to release the drug. Thus, fast-dissolving films offer significant advantages over other solid oral dosage forms. This review provides an overview of the polymers commonly used in drugs classified under BCS Class I to BCS Class IV, as well as factors that influence drug absorption. Solubility and permeability are the main factors that limit the effectiveness of oral fast-dissolving films for drugs in BCS Class II and BCS Class III. It also includes a brief description of the various technologies used in the formulation of oral films, along with the manufacturing process, evaluation methods, and pharmaceutical applications.
Among all dosage forms, oral administration is the most practical and preferred method. Because oral drug delivery systems are non-invasive and versatile, they accommodate a wide range of medications, and over 70% of pharmaceuticals are available in this form1. Dysphagia is a common issue affecting all age groups, leading many people—particularly the elderly and children—to avoid taking solid oral dosage forms due to the risk of choking. In the early 19th century, fast-dissolving tablets (FDTs) were developed to address these swallowing challenges. This led to the development of fast-dissolving films (FDFs). Due to their unique properties, fast-dissolving dosage forms have gained increasing importance. These dosage forms dissolve and disintegrate rapidly and can be administered without water, making them especially useful for the elderly and children. Fast-dissolving films (FDFs) are now commonly used in personal care, food, and medicine delivery industries, along with breath strips 2. Fast-dissolving films can help overcome some of the issues associated with fast-dissolving tablets. The shape, size, and thickness of fast-dissolving films are similar to a thin postage stamp. When applied to the tongue or oral mucosal tissue, saliva quickly moistens the film, causing it to hydrate and adhere to the site of application. The film then dissolves rapidly, releasing the drug for oromucosal absorption. Fast-dissolving drug delivery systems (FDDS) are suitable for drugs that undergo significant first-pass metabolism and can be used to improve bioavailability by reducing the frequency of doses to achieve higher plasma concentrations. This helps reduce side effects and improves cost-effectiveness 3.
ADVANTAGES 4
DISADVANTAGES[5]
FORMULATION COMPONENTS OF FAST DISSOLVING FILM
Table 1: Formulation Table [3]
|
Sr. No. |
Components |
Concentration |
|
1. |
API |
1-25% |
|
2. |
Film-Forming Polymer |
45% |
|
3. |
Surfactant |
Q.S |
|
4. |
Plasticizer |
0-20% |
|
5. |
Sweetening Agent |
3-6% |
|
6. |
Flavoring Agent |
Q.S |
|
7. |
Coloring Agent |
Q.S |
|
8. |
Vehicles |
Q.S |
|
9. |
Saliva Stimulating Agent |
Q.S |
METHODS OF PREPARATIONS FOR THE FILM
These dosage forms are made using a variety of techniques, including casting, spraying, and extrusion 6.
Method of preparation of fast-dissolving films fast-dissolving films can be prepared by:
1) Solvent casting method
In this method, a water-soluble polymer is first dissolved in water at 1,000 rpm and heated to 60°C. All other excipients such as color, aroma, and sweeteners are dissolved separately. The two solutions are mixed thoroughly at 1,000 rpm. The solution is then mixed with the API dissolved in an appropriate solvent. Air is removed from the vacuum cleaner. The resulting solution is poured onto a thin film and dried, then cut into small pieces 7.
Advantages
Disadvantages
Fig.1. Solvent casting method
2) Semisolid casting method
In the semisolid casting method, a solution of a water-soluble film-forming polymer is first prepared. This solution is then added to a solution containing an acid-insoluble polymer (e.g., cellulose acetate phthalate, cellulose acetate butyrate), which is prepared in ammonium or sodium hydroxide. An appropriate amount of plasticizer is then added to form a gel mass. Finally, the gel mass is cast into films or ribbons using heat-controlled drums. The thickness of the film is approximately 0.015–0.05 inches. The ratio of the acid-insoluble polymer to the film-forming polymer should be 1:4 8–9.
Advantages
Disadvantages
3) Hot melt extrusion
Granules, sustained-release tablets, and transdermal and transmucosal drug delivery systems are frequently made via hot melt extrusion. The medicine and carriers are initially combined in solid form using the hot melt extrusion process. The mixture is then melted by the extruder's heaters. Ultimately, the dies shape the melt into films. Polymers with low molecular weight or viscosity, like pullulan PI.20 or HPMC E5, are typically preferred when creating RDFs. The desired physical qualities can also be obtained by combining different grades of polymers. A film with great drug solubility and strong mechanical strength is created by combining polymers with different viscosities. There are several processes in the pharmaceutical industry's wafer manufacturing process 10,11.
Usually, steering speed and temperature control are used to prepare the mass first. The temperature, air circulation, and line speed are once more regulated as the wafers are coated and dried in a drying tunnel. The wafers are then slitted, punched, pouched, and sealed in the final stage. Oral wafers can also be produced by spraying or extrusion, especially hot-melt extrusion.
Advantages
Disadvantages:
Fig.2. Hot Melt Extrusion
4) Solid dispersion extrusion
The distribution of one or more APIs in a solid state in an inert carrier using techniques like hot melt extrusion (HME) in the presence of amorphous hydrophilic polymers is referred to as "solid dispersion." Using this method, the medication is extruded with immiscible components to create solid dispersions. Finally, dies are used to form these dispersions into films 12 .
5) Rolling method.
In the rolling process, the chemical solution and film-forming polymer solution are thoroughly mixed, and the resulting solution is applied to the roller.The solutions or suspensions must have specific rheological properties. The film is dried on the rollers and cut into the desired shape and size 13 .
PHARMACEUTICAL APPLICATION OF ORAL FILM 14:
i) Allergic Reaction
Fast-dissolving films are commonly used to treat allergic reactions due to their rapid and effective response.
ii) CNS Disorder
Oral films are beneficial for treating central nervous system (CNS) disorders due to their quick and efficient action.
iii) Topical Application
The films are used topically as analgesics or antimicrobial agents for wound treatment and healing.
iv) Gastro Retentive Dosage Form
These are used to treat gastrointestinal tract (GIT) disorders.
v) Vaccine
Fast-dissolving films can be used to deliver vaccines for the treatment of various diseases, such as the Rotavirus Vaccine.
EVALUATION PARAMETERS
i) Organoleptic Evaluation
The prepared films are analyzed for their physical properties 15.
ii) Morphology Study
The morphology of the prepared film is examined using scanning electron microscopy at a fixed magnification 16.
iii) Weight Variation
A one square inch piece of film was cut from five different locations on the cast film. The weight of each film strip was measured, and the variation in weight was calculated 17.
iv) Thickness of the Film
The thickness of the film was measured using a screw gauge at various positions along the film. The average thickness was then determined 18 .
v) Tensile Strength
The tensile strength of the film was measured using a digital tensile tester, which includes two load cell grips. One grip was fixed, while the other was movable. A test film of specific dimensions, 3 inches by 10 mm, was placed between the two grips. Force was gradually applied until the film broke 19 .
vi) Percentage Elongation
Percentage elongation was determined using a Hounsfield universal testing machine, which also consists of two load cell grips. The lower grip was fixed, and the upper grip was movable. A test film of the same dimensions (3 inches by 10 mm) was placed between the grips. Force was applied gradually until the film broke. Readings were recorded from the instrument 20 .
vii) Folding Endurance
Folding endurance is defined as the number of times a film can be folded at the same plane before it breaks or develops visible cracks. This test provides insight into the film's brittleness. A small strip measuring 4 square cm was folded repeatedly at the same plane until cracks appeared 21.
viii) Disintegration Time
The disintegration test was conducted using a disintegration test apparatus. A one square inch film was placed in a basket, which was raised and lowered to simulate movement at a rate of thirty times per minute. The time taken for the film to completely disintegrate, leaving no trace above the gauze, was recorded. The test was performed in triplicate 22.
ix) Mouth Dissolving Time
The mouth dissolving time was determined by placing the film manually into a beaker containing 50 ml of 6.8 pH phosphate buffer. The time required for the film to dissolve completely was noted 23.
x) Content Uniformity
The films were tested for content uniformity. A one square inch piece of film was cut and placed in a 100 ml volumetric flask. It was dissolved in methanol, and the volume was adjusted to 100 ml with methanol. The solution was diluted appropriately, and the absorbance was measured at 285 nm 24.
xi) In-Vitro Dissolution Studies
The dissolution profile of the mouth dissolving films was compared with that of the pure drug. The dissolution study was conducted using a USP Type II (paddle) apparatus with 500 ml of 0.1 N HCl containing 0.5% w/v sodium lauryl sulphate as the dissolution medium, maintained at 37 ± 0.5°C. The medium was stirred at 100 rpm for one hour. Samples were collected at 15-minute intervals and replaced with fresh medium. The samples were diluted with methanol and analyzed for drug content at 285 nm 25.
CONCLUSION
The present review concludes that due to issues with dysphagia and the need for emergency treatment, fast oral dissolving films are commonly used. These films improve patient compliance and are easy to administer. Drugs that fall under BCS II and BCS III face challenges in manufacturing due to the rate-limiting step of absorption, even for low-dose drugs. These challenges can be addressed with the use of appropriate polymers. Among various manufacturing methods, solvent casting is the most widely used technique. Other techniques such as wafering, foamburst, and microporation are also employed in the formulation of oral films.
REFERENCES
Dhruv Shah, Ria Patel, Dr. Priyanaka Patil, Fast Dissolving Film as an Alternative to Conventional Oral Dosage Forms, Int. J. of Pharm. Sci., 2026, Vol 4, Issue 1, 1069-1076. https://doi.org/10.5281/zenodo.18213394
10.5281/zenodo.18213394
