Viscosan™ is technically speaking a homogenously (randomly) deacetylated chitin, a polysaccharide built up by N-acetyl-glucosamine and glucosamine units. By keeping a strict control of the deacetylation pattern and degree of deacetylation a number of useful properties can be tailored. Examples of such properties are: biodegradation rate, inflammatory responce, solubility and viscosity. Viscosan™ is manufactured to give products in a typical range from 40% to 70% degree of deacetylation and in different viscosities, see catalogue.
Chitosan is also derived from chitin but has generally a higher degree of deacetylation (80-95%) and a different distribution pattern of its remaing acetyl groups, in litterature often refered to as having a “blockwise” deacetylation pattern. Technically speaking chitosan is a heterogeneously deacetylated chitin.
Both polymers are biodegradable, antimicrobial and mucoadhesive. However, there are differences unique for Viscosan™ and makes it favourable in many applications. In contrast to traditional chitosans, which are practically insoluble at neutral pH and degrade slowly1 when used in vivo, Viscosan™ is soluble at physiological pH2, degrades faster in vivo3, and is less inflammatory4.
The cartoon to the right illustrates the structural differences between chitin, Viscosan™ and Chitosan. The blue line is representing the long polysaccharide, built up by glucosamine, and the black bars are representing acetyl groups.
1. Sannan et. al., Makromol.Chem.177, 3589-3600 (1976)
2. M. Vårum et. al., Carbohydrate Polymers, 25, 65-70, (1994)
3. Tomihata and Y. Ikada, Biomaterials, 18, 567-575 (1997)
4. D. Fang et al., Biomaterials 129, 127-138 (2017)