Mucosal (Sub-lingual and Buccal and Wounds) Drug Delivery Systems
Key staff: Dr Lisa Benée and Dr Joshua Boateng
For non-invasive drug delivery, film is an attractive alternative to tablet and capsule, especially for patients who have difficulty swallowing. Polymeric films containing an active agent can make the delivery either sublingual (under the tongue) or buccal (inside the cheek). In either location, the polymer matrix dissolves and the active is released.
The development of an oral dosage form that does not require swallowing benefits both the consumer and the pharmaceutical industry. By carefully controlling the pH and temperature of the solvent, as well as the type of polymers incorporated, i.e. the degree of hydrophobic modification, polymeric films can be prepared with properties to suit a variety of applications.
Potential applications include the delivery of:
- breath-freshening agents;
- nutriceuticals;
- vitamins;
- caffeine;
- pharmaceutical actives (from poorly soluble to highly soluble).
Recent projects
Modification of polymer viscosity to enhance a given formulation
Polymers are often blended to obtain a suitable viscosity for a specific industrial purpose such as the formulation and manufacture of films. While blending polymers in water, a synergistic interaction can occur, whereby the viscosity of the blend is greater than the sum of the viscosities of the individual components. Understanding these synergies is essential in formulating polymer-based products.
Controlled release of pharmaceutical agents
By careful selection of polymers, films can be prepared that dissolve over time scales from a few seconds to a few hours. This is useful for controlled or sustained release of pharmaceutical agents.
Increasing the “loading” of actives
Modifying polymers by increasing the amount of hydrophobic domains along the polymer backbone can potentially increase the loading of hydrophobic molecules. Research is also underway for improving the drug-loading capacity of fast-dissolving thin films by the combination of different polymer starting materials.
Anti-solvent technologies
For selected polymers, exposure to supercritical fluids can facilitate their swelling more than in water. This increase in swelling exposes hydrophobic domains that would otherwise stay hidden, and loading can therefore be increased without the need for polymer modification.
Wound-healing dressings
Novel polymeric systems (freeze-dried wafers and films) have been developed for the delivery of drugs to wound surfaces.
Publications
Benée, L. S., and Auffret, A. D. (2004) Process for making orally consumable dosage forms. Patent WO2004012720. Pfizer.
Boateng, J. S., Auffret, A. D., Humphrey, M. J., Matthews, K. H., Stevens, H. N. E. and Eccleston, G. M. (2003). Characterisation of freeze-dried and solvent cast drug delivery Systems. J. Pharm. Pharmacol. 55 (Suppl) 149 S-33.
Boateng, J. S., Auffret, A. D., Humphrey, M. J., Matthews, K. H., Stevens, H. N. E. and Eccleston, G. M. (2003). Mechanical and dissolution properties of freeze-dried and solvent cast films. AAPS Pharmsci. 5 (4) s4101.
Boateng, J. S., Matthews, K. H., Stevens, H. N. E. and Eccleston, G. M. (2007). Wound healing dressings and drug delivery systems: A review. J. Pharm. Sci. DOI: 101002/JPS21210, Epub 26 Oct 2007.
Cornelius, V. J., Mitchell, J. C., and Snowden, M. J. (2004) Method for oral drug delivery. Patent application 0420250.3
Cornelius, V . J., Mitchell, J. C., and Snowden, M. J. (2005) Preparation of active containing thin films as novel oral dosage forms. Industrial Pharmacy, 7.