Sonication has been used effectively for a number of polysaccharides.

Enzymatic hydrolysis could be used.

Hi Ibrahim,

Studies have shown that treating your chitosan with strong NaOH solution. NaOH, will break down the chitosan chain and you will have a lower molecular chitosan.

Why you don't try to buy one. Sigma Aldrich they sell it and is not expensive.

Hi ali,

So how much NaOH shall I use? And how to add it?

Dear Ibrahim,

What I have done in the past is I have suspended the chitosan (500 mg) in about 5 mL of 33% w/v NaOH solution and stir the suspension for couple of hours. then. I have sealed the container, put in the freezer for a week. after that. I have taken the suspension and separate the chitosan from the NaOH. by this time you should have a reduction in the chitosan polymer

Hope this helps

Ali