Georgi Yordanov Yes chitosan and their nanoparticles are biodegradable.

Have a look on below attached article

Thanks

Article Co-disposition of chitosan nanoparticles by multi types of h...

Avinash Kumar, thank you for the reference!

Dear Georgi,

Looking in vitro studies looks that chitosan persist long time and could pass from mother to daughter cells through several mitotic cycles.

Article Internalized Chitosan Nanoparticles Persist for Long Time in...

" Many polymers (especially the chitosan) and their nano/microparticles, commonly referred to as biodegradable/biocompatible, have been investigated for drug delivery and other medical purposes; however, the mechanism of their degradation has not been fully elucidated in biological systems. Evidence for their in vitro or in vivo degradation is very limited or conflicting. The FDA has approved some polymers for drug delivery and certain medical applications [5] because their degradation products are deemed to be biocompatible and eliminated from the body. However, once these polymers have formed nanoparticles by crosslinking (either by covalent, ionic or other bonds), it is not known whether those nano/microparticles are entirely biodegradable or biocompatible. "

source:

Article Degradability of chitosan micro/nanoparticles for pulmonary ...

It looks like we currently don't have enough data to say that chitosan doesn't have deep compartments. If it is transmitted from cell to cell in mitotic cycles, this indicates strong binding to cell structures and a very low level of elimination. It is very likely that some fraction of chitosan may be eliminated very slowly and stay in the body for a long time. Chitosan with more 73% degree of deacetylation is hardly degraded. Highly deacetylated chitosan (over 85%) shows a low degradation index in the aqueous environment and will degrade after a few months. This means that the kinetics of elimination of this fraction is non-linear. It also requires the creation of more complex pharmacokinetics models. Until now such models probably are not described in literature.

Best regards

Tomasz