Micro-containers for controlled release of orally administered therapeutics
The objective of the drug delivery activities of the NAMEC centre (New Systems 1 – NS1) is the development of a solution which can overcome some of the obstacles present in oral drug delivery. Our research focuses on the top-down fabrication of a biopolymer micro-container for oral administration of drugs.
Macroscopic tablets and nanoscale drug delivery
For several decades, the classical methods for delivery of therapeutic drugs have not changed. Oral drug delivery using tablets that are dissolved in the digestive system and thereby releasing the active substance is the preferred route to administer medicine to patients. In general, the use of tablets provides good patient compliance and no need for health care professionals. However, a number of challenges remain unsolved:
- The degradation of a large amount of the active pharmaceutical components prevents them from reaching their targets
- Physical barriers such as the surface layer in the intestine (gastro intestinal tract – GIT) hinder adequate absorption
- Drug release from tablets is typically controlled by the intestinal pH gradient, which can result in a release of the components over a large segment of the GIT instead of a defined location.
Non specific delivery of the drug has to be compensated by an increase in the dose which amplifies unwanted side-effects of the medicine. Improved control of place and time of drug release in the GIT would be beneficial for the patients. Additionally, as much as one third of the population, in particular children and elderly people, has problems in swallowing normal sized tablets.
Today, alternative methods for drug delivery are investigated. One of them is the use of nanovesicles or nanoparticles fabricated by bottom-up approaches. Typically self-assembly results in the formation of spherical nanostructures. There, it remains a challenge to control size and to ensure stability of the drug delivery vehicles in stomach and intestine.
Drug delivery in NAMEC: Bridging the gap
The research activities focus on the fabrication of a polymer micro-container serving as vehicle for oral drug delivery. The container is an order of magnitude smaller than conventional tablets and can therefore be easily swallowed by the patient. The container is filled with the drug of interest which is specifically released in the digestive system. The amount of released medicine is exactly defined by the volume of the container. The complete micro-container is fabricated using a biopolymer which ensures bio-compatibility and avoids the accumulation of harmful residues in the human body. Additionally, control of surface properties supports oriented attachment of the containers with the open side towards the intestine wall. This allows unidirectional drug release and prevents degradation of the medicine.
Partners and tasks
The different partners and their main contributions to the development of the micro-containers for oral drug delivery are illustrated in the following scheme. Click on a specific topic to learn more details about the research activities:
References
F.J. Martin, C. Grove, "Microfabricated drug delivery systems: Concepts to improve clinical benefit", Biomedical Microdevices 3:2 (2001) 97-108
A. Ahmed, C. Bonner, T.A. Desai, "Bioadhesive microdevices with multiple reservoirs: a new platform for oral drug delivery", Journal of Controlled Release 81 (2002) 291-306)
Contact:
Stephan S. Keller, project coordinator of work package
Office: room 153, bldg. 345 East tel: +45 4525 5846
Email: stephan.keller@nanotech.dtu.dk