Implant material

#This application is the U.S. National Stage of International Application No. PCT/CH2006/000589, filed Oct. 23, 2006.

#The present relates to the field of dental and bone surgery. In particular, the invention relates to fibrous pharmaceutical compositions; fibrous webs of such pharmaceutical compositions; to implant material essentially consisting of fibrous pharmaceutical compositions; to the manufacturing and use of such fibers/webs/implant materials.

#Materials for dental and bone surgery. Next to numerous permanently implanted materials both consisting of ceramic, metals, polymers or combinations of two or all three, more recent development has started to provide biodegradable materials that remain only temporarily in the human body. Many of the investigated materials are partly or fully composed of calcium phosphates, such as hydroxyapatite or tricalcium phosphate (TCP) tracing back to the fact that bone mineral mainly consists of a complex form of carbonated hydroxyapatite. Moreover, such materials are considered osteoconductive and allow for direct bonding to bone while in some cases they were even assumed to be precursors to bone apatite formation. These materials are slowly dissolved and can successively be re-sorbed, degraded and replaced by own tissue from the patient. More specifically, dental and bone surgery has strongly profited from the development of degradable implants, especially for the treatment of younger patients (0-60 years). Within most application, a bone implant material is used to fill a defect (loss of natural bone at a given site in the skeleton or dental parts) or sustain a specific function (e.g. keep an artificial hip implant in place and transfer the forces from the leg onto the implanted shaft). More specifically, the area of degradable materials can be divided from a materials point of view into the following major material groups Degradable Metal implants (which are not relevant in the context of the present invention); Degradable Polymer implants and Degradable. Ceramic implants and Degradable Composites.

#The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed figures, wherein:

#FIG. 1 shows a transmission electron microscopy image of as-prepared amorphous tricalcium phosphate (ATCP) nanoparticles (a); the corresponding hydrodynamic particle size distributions of ATCP measured by X-ray disk centrifugation (b); a photograph of as-electrospun PLGA/ATCP scaffold prepared into cotton-like biomaterial (c).

#FIG. 2 shows scanning electron microscopy images of as-electrospun scaffolds: PLGA/ATCP 100:0 overview (a) and close-up (b), PLGA/ATCP 60:40 overview (c) and close-up (d).

#In a first aspect, the invention relates to a pharmaceutical composition in the form of fibers comprising one or more biodegradable polymers and one or more biodegradable inorganic nanoparticles having a mean primary particle size below 500 nm and optionally pharmaceutically active ingredients and/or proteins.

#Biodegradable polymers: In the context of this invention, a wide variety of biodegradable polymers, derived from artificial or natural sources, may be used. To choose the appropriate polymer; the degradation time and manufacturing properties will be considered. Such polymers are commercially available or may be manufactured according to known procedures. Examples of suitable polymers (homopolymers, co-polymers and its blends) can be divided into two subsections as described in (Hayashi, T., “Biodegradable Polymers for Biomedical Uses”, Progress in Polymer Science, 1994, 19, 633):

#i) Enzymatically degradable polymers: This section includes natural polypeptides (e.g. collagen, gelatin, albumin, fibrinogen), synthetic polypeptides (e.g. poly(L-glutamic acid), poly-L-lysin, poly-L-leucine, poly-L-alanine), polysaccharides (e.g. amylase, Hydroxyethylstarch, dextran, alginic acid, chitin, chitosan), and biopolyesters (e.g. poly(β-hydroxyalkanoate).