carboxymethyl chitosan

I am looking for methods to make N,O-carboxymethyl chitosan. I have found one in an expired US patent and another in a 20 year old journal
article. Just wondering if anyone knows of more recent published methods or could forward a copy. Thanks!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dr Boudreaux wrote:

Do any patents reference the expired one?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.