Chitosan is a natural polysaccharide derived from the shells of crusteaceans and is a well-studied biopolymer that is nontoxic, biocompatible, biodegradable and mucoadhesive. Chitosan has been widely used in biomedical, cosmetic and food industries. The main drawback of using chitosan in the delivery of therapeutics and for tissue generation applications is that it is insoluble at physiological conditions of pH and tonicity. It only can be dissolved in acidic solutions below pH<6.2 this pH is detrimental to living cells as well as sensitive therapeutics such as proteins, which tend to get denatured at this pH.

Laval, Québec Canada-based Biosyntech has developed a family of injectable thermogelling polymer solution called BST-Gel. BST-Gel is a proprietary formulation (US Patent 6344488) of chitosan in an aqueous solution, which allows this polymer to be used effectively for tissue regeneration and local delivery of sensitive therapeutics. Biosyntech's technology allows for the preparation of a chitosan solution with physiological pH (approximately 7.0) and tonicity (approximately 350mOsmol/kg) thus allowing for the mixing of living cells and the maintenance of their viability, as well as the mixing of other therapeutics that require these gentle conditions for delivery.

The aqueous formulation of BST-Gel is also thermosensitive. It can be held as a liquid solution at cold temperature (below room temperature), but turns into a solid-like gel when heated to a higher temperature (approximately 37 degrees C) such as that occurring upon injection into body sites. Thus the liquid form may be mixed with cells and therapeutics at low temperature and injected into a body where it solidifies and retains the cells or therapeutics at the injected sites. The encapsulated cells then perform normally and the therapeutics encapsulated will be slowly released into the local environment. In these types of applications the nontoxicity, biocompatibility, biodegradability and adhesiveness of chitosan are the essential characteristics of this technology.

Talking about the applications of this particular delivery platform, Matthew Shive, vice president of product development at Biosyntech comments, "BST-Gel is formulated at physiological conditions totally free from any organic cross-linker or solvent. Furthermore, its ability to be held liquid at or below the room temperature and turning into stiff gel when heated up to around 37 degrees C, makes it an ideal candidate for designing injectable delivery systems. In the field of drug delivery, BST-Gel has demonstrated superior performance since it has showed a positive compliance with all the requirements needed for a successfully delivery system."

Separate studies have also revealed that BST-Gel loaded with an osteogenic protein proved to be effective in promoting bone formation. Two weeks after local injection of BST-Gel containing bone morphogenetic protein onto the tibia periosteum of a rat resulted in a rapid bone proliferation. The newly formed bone was detected by radiology and evidenced by micro-CT images.

Biosyntech's lead products in a strong pipeline are BST-CarGel, a degradable implant for cartilage repair, as well as BST-DermOn, a chronic-wound treatment and BST-InPod, a therapy against heel pain. BioSyntech's portfolio also includes BST-OssiFil, a bone consolidation material, BST-Disc, an intervertebral disc restoration treatment and Arthro-BST, an arthroscopic device used to assess the quality of cartilage.

"We have obtained a broad IP coverage of the gel technology, and are constantly improving it by filing patent uses on specific applications. We currently have 51 filed patents covering 15 applications. So far 15 patents have been issued," says Shive.

The company is currently seeking collaborations for the development of new applications of its platform technology. The company has certain collaborations already ongoing with industrial partners in specific fields such as gynecology, capillary transplant, ophthalmology and bone regeneration.

Details:

Matthew Shive, VP, Product Development

BioSyntech Inc., 475 Armand-Frappier Blvd

Laval, Quebec, Canada H7V 4B3

Phone: 450-686-2437 Extn. 246

E-mail: shive@biosyntech.com

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