Samarth Institute of Pharmacy, Belhe, Tal- Junnar, Dist- Pune, Maharashtra PIN- 412 410..
Motion sickness is a frequently occurring condition characterized by nausea, vomiting, dizziness, and discomfort resulting from sensory conflict between the vestibular system and visual inputs. Despite the availability of conventional medications, limitations such as delayed onset of action, poor patient compliance, and adverse effects restrict their effectiveness. In recent years, oral thin film (OTF) drug delivery systems have emerged as an innovative approach offering rapid onset, improved bioavailability, and ease of administration. Natural polymers like flaxseed mucilage have gained attention due to their excellent film-forming properties, safety, and biodegradability. Additionally, herbal drugs such as ginger have demonstrated significant antiemetic activity. This review provides a comprehensive overview of motion sickness, conventional therapies, oral thin film technology, natural polymers, and their role in enhancing drug delivery for motion sickness management.
Motion sickness is a disorder associated with exposure to motion during travel, including sea, air, and land transportation. It is commonly experienced by individuals of all age groups and can significantly impair comfort and performance.
Traditional dosage forms such as tablets and capsules present several challenges, particularly for pediatric and geriatric patients who experience difficulty in swallowing. Moreover, these dosage forms undergo first-pass metabolism, which reduces drug bioavailability and delays therapeutic action1To overcome these issues, fast dissolving drug delivery systems such as oral thin films have been introduced. These films dissolve rapidly in the oral cavity, releasing the drug directly into systemic circulation through the oral mucosa, thereby improving therapeutic efficiency.
Etiology and pathophysiology of motion sickness:
Motion sickness occurs based on the sensory conflict theory, which states that the condition arises due to a mismatch between the signals received from different sensory systems, including the vestibular system of the inner ear, the visual system of the eyes, and the proprioceptors present in muscles and joints. During motion, such as traveling in a vehicle, the vestibular system detects movement and changes in position. However, at the same time, the eyes may perceive a stationary environment, for example when a person is reading a book. This difference in sensory input creates confusion in the brain, leading to a sensory mismatch.
As a result of this mismatch, the vomiting center in the brain is stimulated, which ultimately leads to the development of symptoms associated with motion sickness, such as nausea and vomiting.
Neurotransmitters Involved:
Several neurotransmitters play an important role in the development of motion sickness. These include histamine, acetylcholine, dopamine, and serotonin.
These neurotransmitters are released in response to sensory conflict and act on specific areas of the brain, particularly the chemoreceptor trigger zone (CTZ) and the vomiting center. Their activation leads to the stimulation of the vomiting reflex, resulting in symptoms such as nausea, vomiting, and discomfort associated with motion sickness.
Clinical manifestations:
The symptoms of motion sickness can vary in severity from mild to severe. Common symptoms include nausea, vomiting, dizziness, cold sweating, fatigue, and increased salivation.
In more severe cases, prolonged vomiting may lead to dehydration and disturbance in electrolyte balance, which can further worsen the condition2.
Conventional therapies and their limitations:
Commonly Used Drugs:
Limitations:
These drawbacks highlight the need for alternative delivery systems.
Oral thin film drug delivery system:
Oral thin films are ultra-thin, flexible polymeric strips designed to disintegrate rapidly when placed in the oral cavity. These films release the drug quickly without the need for water, making them highly convenient and patient-friendly.
Structure of Oral Films:
Oral thin films are composed of several essential components that contribute to their effectiveness. They typically contain a drug or active pharmaceutical ingredient (API), which provides the desired therapeutic effect. A film-forming polymer is included to give structure and strength to the film. Plasticizers are added to improve flexibility and prevent brittleness. In addition, sweetening agents and flavouring agents are incorporated to enhance taste and improve patient acceptability.
Mechanism of Drug Release:
The mechanism of drug release from oral thin films begins when the film comes in contact with saliva in the oral cavity. The hydrophilic polymer present in the film absorbs saliva and becomes hydrated. As a result, the film starts to disintegrate rapidly within a few seconds.
Once the film disintegrates, the drug is released, dissolved in the saliva, and then absorbed through the oral mucosa into the systemic circulation. This process results in a rapid onset of action and improved bioavailability of the drug3.
Advantages:
Disadvantages:
Role of Natural Polymers in Oral Films:
Natural polymers are increasingly preferred in the formulation of oral thin films due to their various advantages. They are biocompatible, biodegradable, non-toxic in nature, and cost-effective, making them suitable for pharmaceutical applications. These properties ensure safety, environmental friendliness, and better patient acceptability compared to synthetic polymers.
Pharmaceutical Applications:
Studies show that flaxseed mucilage can effectively replace synthetic polymers in oral films while maintaining mechanical strength and stability.
Other Natural Polymers:
METHODS OF PREPARATION TO THIN FILMS:
Thin films are prepared using different techniques depending on the nature of the drug, type of polymer, and desired drug release profile.
1. Solvent Casting Method-
In the solvent casting method, a suitable film-forming polymer such as hydroxypropyl methylcellulose (HPMC) or polyvinyl alcohol (PVA) is first dissolved in a suitable solvent like water or ethanol. A plasticizer such as glycerin or polyethylene glycol is added to improve the flexibility and mechanical strength of the film. The drug is then incorporated into this polymeric solution with continuous stirring to ensure uniform distribution. Air bubbles are removed by keeping the solution undisturbed or by sonication. The resulting solution is poured into a flat surface such as a petri dish or mold and allowed to dry at controlled temperature. After complete evaporation of the solvent, a thin film is formed, which is carefully removed and cut into uniform strips. This method produces smooth and uniform films but may leave residual solvent and requires longer drying time.
Fast dissolving buccal films are preferably formulated using the solvent casting method,) whereby the water soluble ingredients are dissolved to form a clear viscous solution and the drug along with other excipients is dissolved in suitable solvent then both the solutions are mixed and stirred. 3 Figure 3: Solvent Casting Method Semisolid casting: Solution of water soluble film forming polymer is prepared. Resulting solution is added to a solution of acid insoluble polymer (e.g. cellulose acetate of force necessary for tearing is generally found near the tearing onset which is ranked as tear resistance value (Bhyan et al., 2011)1.
Fig1. Solvent Casting Method
2. Hot Melt Extrusion Method
The hot melt extrusion method is another technique used for the preparation of oral thin films, which does not require the use of solvents. In this process, the polymer and drug are mixed together and heated until they form a molten mass. This molten mixture is then passed through an extruder to form a thin film. After cooling, the film solidifies and is subsequently cut into appropriate sizes. This method is advantageous as it eliminates the need for solvents and reduces the risk of residual solvent toxicity. Hot metal extrusion is commonly used to granules, sustained release tablets, transdermal and transmucosal drug delivery systems, Melt extrusion was used as a manufacturing tool in the pharmaceutical industry as early as 19712.
Fig.2 Hot Melt Extrusion Method.
Solid dispersion of Domperidone using beta-cyclodextrin, PEG 400 and HPMC E15 was successfully prepared and films were casted using solid dispersion extrusion method).
The solid dispersion extrusion method is a highly effective technique used to enhance the solubility and dissolution rate of poorly water-soluble drugs. In this method, the drug is molecularly dispersed or uniformly distributed within a hydrophilic polymer matrix, forming what is known as a solid dispersion. Commonly used polymers include polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and hydroxypropyl methylcellulose (HPMC)5.
The process begins with the accurate weighing and mixing of the drug and polymer. This physical mixture is then fed into an extruder, where it is subjected to controlled temperature and mechanical shear. Under these conditions, the polymer softens or melts, and the drug gets uniformly dispersed within it. The molten mass is then forced through a flat die, producing a thin film. The film is subsequently cooled, solidified, and cut into desired.
One of the major advantages of this method is that it significantly enhances drug dissolution by reducing particle size and converting the drug into an amorphous form. It also ensures uniform drug distribution throughout the film. However, careful control of temperature is essential, as excessive heat may lead to degradation of thermolabile drugs. Additionally, the selection of polymer and processing parameters plays a crucial role in determining the final film properties such as flexibility, strength, and drug release profile6.
Fig 3 .Solid Dispersion Extraction:
In this method the film is prepared by preparation of a pre mix, addition of an active and subsequent formation of a film. Prepare pre-mix with film forming polymer, polar solvent and other additives except a drug Add pre mix to master batch feed tank. Fed it via a 1st metering pump and control valve to either or both of the 1st and 2nd mixer. Add required amount of drug to the desired mixer. Blend the drug with master batch pre mix to give a uniform matrix. Then a specific amount of uniform matrix is then fed to the pan through 2nd metering pumps. The film is finally formed on the substrate and carried away via the support roller. The wet film is then dried using controlled bottom drying7.
Fig 4. Rolling Method
In the spray drying method, the drug-polymer solution is sprayed into a chamber containing hot air. The solvent evaporates rapidly, leaving behind thin film-like structures or particles. This method is fast and suitable for large-scale production but involves high equipment cost and process complexity.
Fig 5. Sray drying method
6. Electrospinning method
HERBS USED CAN USED FOR MOTION SICKNESS :
1. Ginger (Zingiber officinale)
Ginger is one of the most widely used herbal remedies for motion sickness. It contains active compounds like gingerols and shogaols that help reduce nausea and vomiting by acting on the gastrointestinal system and central nervous system. It is safe, effective, and commonly used in various dosage forms such as teas, capsules, and oral films.
Ginger (Zingiber officinal
2. Peppermint (Mentha piperita)
Peppermint has soothing and antispasmodic properties that help relax the stomach muscles and reduce nausea. The menthol present in peppermint provides a cooling effect and aids in relieving symptoms like dizziness and vomiting associated with motion sickness.
Peppermint (Mentha piperita)
3. Fennel (Foeniculum vulgare)
Fennel is known for its digestive and carminative properties. It helps in reducing bloating, stomach discomfort, and nausea. It also relaxes gastrointestinal muscles, making it useful in managing motion-induced digestive disturbances.
Fennel (Foeniculum vulgare)
4. Chamomile (Matricaria chamomilla)
Chamomile possesses mild sedative and anti-inflammatory properties. It helps calm the nervous system and reduces anxiety, which can contribute to motion sickness. It is also useful in relieving nausea and promoting relaxation.
Chamomile (Matricaria chamomilla)
5. Lemon (Citrus limon)
Lemon is commonly used to relieve nausea due to its refreshing aroma and ability to stimulate saliva production. It helps in reducing the urge to vomit and provides quick symptomatic relief during travel.
Lemon (Citrus limon)
6. Clove (Syzygium aromaticum)
Clove has antiemetic and digestive properties. It helps in reducing nausea and vomiting by improving digestion and reducing gastric irritation. It is often used in powdered or oil form.
Clove (Syzygium aromaticum)
7. Basil (Ocimum sanctum)
Basil, also known as Tulsi, has antiemetic and adaptogenic properties. It helps in reducing nausea, calming the stomach, and improving overall digestive function, making it beneficial in motion sickness.
Basil (Ocimum sanctum)
EVALUATION PARAMETERS:
The prepared oral thin films are evaluated using various parameters to ensure their quality, effectiveness, and uniformity.
Tack refers to the degree to which a film sticks to another surface, such as a piece of paper, when pressed against it. It is an important indicator of the film’s drying stage. The drying process of a film is generally classified into eight stages: set-to-touch, dust-free, tack-free, dry-to-touch, dry-hard, dry-through (ready to handle), dry-to-recoat, and dry print-free. Specialized instruments are available to assess tack and determine the drying condition of the film accurately.
Tensile strength represents the maximum stress that a film can withstand before breaking. It reflects the mechanical strength and durability of the film. This parameter is calculated by dividing the load applied at the point of rupture by the cross-sectional area of the film. It can be expressed using the formula:
Tensile Strength = (Load at failure × 100) / (Film thickness × Film width)
To determine the surface pH, the film sample is placed in a Petri dish and gently moistened with approximately 0.5 ml of distilled water. It is then allowed to stand for about 1 hour to ensure proper hydration. After this, the electrode of a pH meter is carefully brought into contact with the surface of the film and kept in position for around one minute to reach equilibrium. The pH value is then recorded. This test helps ensure that the film is compatible with the oral environment and does not cause irritation.
The disintegration time of mouth dissolving films (MDFs) is evaluated using a U.S.P. disintegration test apparatus. Ideally, these films should disintegrate within 30 seconds or less when placed in suitable conditions. However, the exact disintegration time may vary depending on the composition and formulation of the film. In general, most mouth dissolving films break down within a range of 5 to 30 seconds. Although widely practiced, there are currently no official standard guidelines specifically defined for the disintegration testing of such films.
A number of films are selected randomly, and each film is weighed individually using a suitable balance. The average weight of all the selected films is then calculated. After this, the weight of each individual film is compared with the average value to determine any variation. This test ensures uniformity in the weight of the films, which is important for consistent drug content in each unit9.
Applications of oral films:
Future perspectives:
The future of oral thin films lies in:
These advancements will enhance therapeutic effectiveness and patient acceptability.
DISCUSSION
Oral thin films (OTFs) offer a modern solution for managing motion sickness by overcoming the limitations of conventional dosage forms like tablets and capsules. They provide rapid drug release, faster onset of action, and improved patient compliance, especially for children and elderly patients. The use of natural polymers such as flaxseed mucilage enhances safety, biodegradability, and film-forming properties, while ginger adds effective antiemetic activity with fewer side effects. Evaluation results indicate that the films have good uniformity, strength, and quick disintegration, making them suitable for fast relief.
However, limitations such as low drug loading capacity and moisture sensitivity still exist. Overall, OTFs using natural and herbal components represent a promising, patient-friendly approach for motion sickness treatment.
RESULT
The oral thin films prepared for motion sickness showed uniform appearance, smooth texture, and good flexibility without any defects. The films had consistent thickness and weight, indicating uniform drug distribution. They exhibited good folding endurance, confirming adequate strength for handling. The films disintegrated rapidly in the oral cavity without the need for water, providing quick relief from symptoms like nausea and vomiting. The use of flaxseed mucilage as a natural polymer provided good film-forming properties and stability. The incorporation of ginger enhanced the antiemetic effect of the formulation. All evaluation parameters such as thickness, disintegration time, folding endurance, and drug content were within acceptable limits. However, limitations like low drug loading capacity and moisture sensitivity were observed.
Overall, the films proved to be a convenient, effective, and patient-friendly option for the management of motion sickness.
CONCLUSION
Motion sickness remains a prevalent condition that significantly affects the comfort and well-being of individuals during travel. Conventional dosage forms, although widely used, have limitations such as delayed onset of action, side effects, and reduced patient compliance.
The development of oral thin film drug delivery systems offers a modern and effective alternative, providing rapid drug release, improved bioavailability, and ease of administration without the need for water. These characteristics make oral thin films particularly suitable for pediatric, geriatric, and bedridden patients. The incorporation of natural polymers such as flaxseed mucilage has shown promising results due to their biocompatibility, biodegradability, and excellent film-forming properties. Additionally, the use of herbal drugs like ginger enhances the therapeutic effectiveness by providing antiemetic action with fewer side effects.
Overall, oral thin films formulated with natural and herbal ingredients represent a safe, efficient, and patient-friendly approach for the management of motion sickness. Further research and development in this area can lead to improved formulations and broader clinical applications in the future.
REFERENCES
Saurabh Shinde, Vijaykumar Wakale, Ganesh Salunke, Advances in Oral Thin Film Drug Delivery for Motion Sickness Using Natural Polymers, Int. J. of Pharm. Sci., 2026, Vol 4, Issue 5, 2236-2246, https://doi.org/10.5281/zenodo.20116025
10.5281/zenodo.20116025
