This article only describes one highly specialized aspect of its associated subject. Please help improve this article by adding more general information. (September 2009)

This section may stray from the topic of the article. Please help improve this section or discuss this issue on the talk page. (September 2009)

Thin film drug delivery is a process of delivering drugs to the systemic circulation via a thin film that dissolves when in contact with liquid, often referred to as a dissolving film or strip. Thin film drug delivery has emerged as an advanced alternative to the traditional tablets, capsules and liquids often associated with prescription and OTC medications. Similar in size, shape and thickness to a postage stamp, thin film strips are typically designed for oral administration, with the user placing the strip on or under^{[citation needed]} the tongue or along the inside of the cheek. As the strip dissolves, the drug can enter the blood stream enterically, buccally or sublingually.

The first commercial non-drug product to use thin films was the Listerine PocketPaks breath freshening strips. Since then, thin film products for other breath fresheners, as well as a number of cold, cough, flu and anti-snoring medications, have entered the marketplace. There are currently several projects in development that will deliver prescription drugs utilizing the thin film dosage form.^[1]

[edit] Advantages

The design of thin film, often referred to as PharmFilm, as an oral drug delivery technology offers several advantages over other modes of drug delivery, such as ingestible tablets, chewable tablets, orally dissolving tablets, softgels, liquids or inhalants:^[2]

• The sublingual and buccal delivery of a drug via thin film has the potential to improve the onset of action, lower the dosing, and enhance the efficacy and safety profile of the medicament.
  • All tablet dosage forms, softgels and liquid formulations primarily enter the blood stream via the gastrointestinal tract, which subjects the drug to degradation from stomach acid, bile, digestive enzymes and other first pass effects. As a result, such formulations often require higher doses and generally have a delayed onset of action.
  • Conversely, buccal and sublingual thin film drug delivery can avoid these issues and yield quicker onsets of action at lower doses.
• Thin film is more stable, durable and quicker dissolving than other conventional dosage forms.
• Thin film enables improved dosing accuracy relative to liquid formulations since every strip is manufactured to contain a precise amount of the drug.
• Thin film not only ensures more accurate administration of drugs but also can improve compliance due to the intuitive nature of the dosage form and its inherent ease of administration. These properties are especially beneficial for pediatric, geriatric and neurodegenerative disease patients where proper and complete dosing can be difficult.
• Thin film’s ability to dissolve rapidly without the need for water provides an alternative to patients with swallowing disorders and to patients suffering from nausea, such as those patients receiving chemotherapy.
• Thin film drug delivery has the potential to allow the development of sensitive drug targets that may otherwise not be possible in tablet or liquid formulations.
• From a commercial perspective thin film drug delivery technology offers an opportunity to extend revenue lifecycles for pharmaceutical companies whose drug patent is expiring and will soon be vulnerable to generic competition.

[edit] Keys to thin film drug development

[edit] Taste masking

An important aspect of thin film drug delivery technology is the masking of the often bitter and poor taste of drug formulations.^[2] One method of taste-masking is encapsulation, the coating of drug particles with a polymeric covering sufficient to mask the taste of the drug particle while maintaining the ability to release the drug for absorption.

Encapsulation is an efficient method for combining a high ratio of drug-to-non-drug elements in the taste-masked particle. Another method is the use of an ion exchange resin to bind the drug, forming a resinate that is less bitter than the drug alone.

[edit] Drug content uniformity

Drug content uniformity is a requirement for all dosage forms, particularly those containing low dose highly potent drugs. To uniquely meet this requirement, thin film formulations contain uniform dispersions of drug throughout the whole manufacturing process.^[3] Since this criteria is essential for the quality of the thin film and final pharmaceutical dosage form, the use of Laser Scanning Confocal Microscopy (LSCM) was recommended to follow the manufacturing process.^[4]

[edit] Avoiding drug degradation

Sensitive drugs may degrade over time in an aqueous environment. Thin film formulations must ensure that the integrity of the drug remains constant over time.^[5]

To overcome these challenges, developers of thin film have created highly specialized unique and often proprietary processes to deliver drugs on thin film.^[6]

[edit] Availability

There are not yet many medications available in a thin film form on the market. Those that are include:

• Benadryl
• Gas-X
• Melatonin PM
• Orajel Kids
• Sudafed
• Suppress
• TheraFlu
• Triaminic

An application to the Food and Drug Administration (United States) for a thin-film formulation of ondansetron has been accepted and is currently under review.^[7]

[edit] Notes

[edit] References

• Hariharan, Madhu; Bogue, B. Arlie (February 2009). "Orally Dissolving Film Strips (ODFS): The Final Evolution of Orally Dissolving Dosage Forms". Drug Delivery Technology (Montville, New Jersey) 9 (2): 24-29. ISSN 1537-2898. OCLC 48060225. http://www.drugdeliverytech-online.com/drugdelivery/200902/?pg=24. 

[edit] External links

• It's On The Tip Of Your Tongue - BusinessWeek (7/31/06)
• How do you want your cold medicine? – Associated Press (10/10/05)