Liqui-Patch: A Sprayable Transdermal Drug Delivery Technology


This is a sponsored article and the author is Dr. Wolfgang Kehr, the CEO of epinamics, a Berlin-based, privately owned research and development company, focusing on an innovative drug delivery technology for dermal and transdermal applications of cosmetic, pharmaceutical and veterinary products. 

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The human skin is a readily accessible surface for drug delivery and therapeutic interventions. However, optimum therapeutic outcomes require proper drug selection and effective drug delivery. Two clinical routes, transdermal drug delivery – the delivery of active pharmaceutical ingredients (API) across the skin and into systemic circulation using e.g. patches or gels – and topical, via local drug penetration are readily available.

At present only a small number of transdermal drug delivery systems are available. epinamics has developed a unique polymer-based, easy to use, highly elastic, film-forming formulation which builds a thin, almost invisible film with various types of active pharmaceutical ingredients for topical and transdermal applications. The formulation mixture is registered under the name: Liqui-Patch®.

Liqui-Patch® platform technology allows the effective formulation and sustained delivery of pharmaceutical ingredients via the skin. Liqui-Patch® has advantages over currently available patch- or gel-based products in safety, efficacy, cosmetic acceptability and metered-dosing. Accordingly, applications with Liqui-Patch® assure increased convenience and compliance.

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Advantages of Transdermal Drug Delivery

Transdermal drug delivery offers several important advantages over traditional oral dosage forms. The steady permeation of a drug across the skin elicits more even serum drug levels, often a goal in therapy. Intravenous infusion also achieves even plasma levels, but it is more invasive, cost intensive and inconvenient. In addition, if adverse effects were to develop from a transdermally administered drug, the effects could be limited by removing the patch or the gel.

Transdermal drug delivery can be used as an alternative route of administration to accommodate patients who cannot tolerate oral dosage forms:

  • It is of great advantage in patients suffering from gastrointestinal disorders, nausea, and emesis.
  • Drugs that cause gastrointestinal upset can be good candidates for transdermal delivery because this method avoids direct effects on the stomach and intestine.
  • Drugs which are degraded by the enzymes and acids in the gastrointestinal system or metabolized by the liver are also good targets.
  • First pass metabolism* by the liver, an additional limitation to oral drug delivery, can be avoided.

*First pass metabolism is a phenomenon of drug metabolism whereby the concentration of a drug is greatly reduced before it reaches the systemic circulation (Wiki).

Weaknesses of current Transdermal Drug Delivery Systems

Local tolerance issuesLocal irritation at the site of application including redness, itching, and local edema. Therapies might be discounted upon allergic reactions. Moreover, glue residues and gels leave a dirty appearance at the application site.

Cross-contaminationCross-contamination to other people through direct skin contact or remaining residue on the hands following application is a major safety concern.

Low skin penetration rate of APIsUp to 90% of the total API in the transdermal patch still remains in the patch after application, due to its low penetration rates on the skin or it stays and is washed off, in case of gels. They are thus, a tremendous ecological burden on our ecosystem.

The Liqui-Patch® Answer

Our Liqui-Patch® platform technology is changing the foundation for effective therapeutic interventions, redefining the terms “Metered Transdermal Drug Delivery” and “Aesthetic Medicine“.

The Film-Forming Polymer

A robust but thin film on the skin and a high concentration of dissolved API within the film is a pre-requisite for sustained API skin penetration, and it distinguishes the Liqui-Patch® technology from transdermal gels. The polymer is a key component of the formulation that makes Liqui-Patch® unique. Transdermal gels do not provide release characteristics comparable to the Liqui-Patch® film-forming technology. This is primarily due to the fact that gelling agents are not selected for their film-forming ability.

Supersaturation without Crystallization of the Active Ingredient

In addition to gels, solutions of drugs with or without additives in volatile solvents have been or are being developed as dermal and transdermal products. Without a film-forming polymer, the volatile solvents (e.g. alcohols) evaporate quickly, resulting in saturation and thus frequently leading to crystallization of the active pharmaceutical ingredients. This causes up to 90% of the active compounds to stay on the skin surface and not reach the systemic circulation. As a result, high volumes of gel or solution per single dose have to be applied on large skin surface areas. Thus, active ingredient residues are usually not fixed to the skin and pose the risk of cross-contamination.

epinamics’ Liqui-Patch® technology addresses these drawbacks.

Recrystallization of the APIs is prevented by the polymer leading to a supersaturated solution. As a result, permeation of the active ingredient into the skin is increased and takes place on a permanent basis. Thus, very small volumes (50 to 150 µl) of a film-forming formulation can be applied onto small skin surface areas. Depending on the properties of the individual pharmaceutical ingredient, skin penetration may be increased by up to five-fold with Liqui-Patch®. Therefore, Liqui-Patch® putatively reduces the ecological burden that comes with hazardous pharmaceuticals waste.

skin penetration

Convenience & Compliance

  • Cosmetic Acceptability √– flexible, readily adhering and non-sticky film
  • Metered Dosing √
  • Efficacy √– highly concentrated, non-crystalline pharmaceutical ingredients
  • Safety √– restricted to small skin surface areas; minimal cross-contamination
  • Flexible Application √– roll-on or airless pump-sprays
  • Reduced Ecological Burden √– minimal wastage and disposal of drug
Credit: epinamics
Credit: epinamics

Product Development

epinamics’ film forming technology is a platform technology, suitable for the development of dermal, cosmetic and transdermal applications for human and veterinary use, as either prescription or Over-the-counter (OTC) medical products.

epinamics has successfully performed feasibility studies for more than 50 pharmaceutical ingredients, 10 cosmeceuticals, and 2 veterinary products. Now, epinamics is initially focusing on the development of 3 transdermal and 1 dermal product for highly attractive therapeutic and cosmetic indications, respectively. A placebo-controlled skin tolerance study of API-free Liqui-Patch® on 20 healthy volunteers has been performed. The 4 weeks lasting routine of daily intra-individual applications of the test product revealed a 100% skin tolerance of the Liqui-Patch® formulation. All of the products developed by epinamics have properties which address remaining or unmet medical but also ecological needs, and can be considered low-risk developments based on the proven efficacy of the active ingredients in the indications and their particular suitability for film-based applications.

Partnering opportunities

The Liqui-Patch® drug delivery technology is the subject of a granted EU, Australian, Canadian, Chinese, Japanese, South-Korean, Mexican, Russian, South-African and US patent. epinamics is the exclusive owner of all patent rights.

We invite companies, interested in the Liqui-Patch® platform technology, to explore potential joint product developments with epinamics. Also, epinamics is willing to license its platform technology to companies for the development of their own APIs. epinamics` innovative drug delivery technology provides the opportunity for Life Cycle Extension and the development of patent-protected “generic API” with clear-cut advantages and short time to market.

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