Individual drug-delivery-systems for medical devices
A conventional administration of drugs may lead to a substantial loss of activity of the agent before reaching the target tissue due to its limited metabolic stability. Targeted drug-delivery-systems (DDS) represent an effective alternative because the agent can be released directly at the target tissue in defined concentrations.
Our research focuses on the development of drug-delivery-systems for medical implants that support the healing of the surrounding bone. Potential active substances therefor are antibiotics, growth factors and cancer statics. The local release can be achieved by a modification of conventional implants, e.g. endoprotheses or bone spare materials enabling in addition to their actual role the function of an adaptable release system for topical therapy.
Absorbable polymermatrices based on lactic acid polyesters serve as substrate for the active substances. Different block copolymers with varying sequences can be synthesized by varying the ratio of the educts. The incorporation of the agents is performed e. g by pestling with support media and subsequent mixing with the oligo-L-lactid macromer. Radical curing of the mixtures leads to stabile solid bodies. Here, two different application forms can be realized: on one hand the mixture can be hardened outside the implant site followed by mechanical forming (model „stick", left picture), on the other hand the mixture can be cured directly inside of the bone defect (model „paste", right picture).
The cytocompatibility of the polymers and the entire system was proven in in-vitro-investigations using a mouse fibroblast cell line.
Dr. Thorsten Laube