The Open Drug Delivery Journal

2008, 2 : 20-25
Published online 2008 March 13. DOI: 10.2174/1874126600802010020
Publisher ID: TODDJ-2-20

Preparation of Carboxymethyl-chitin Nanoparticles by Covalent Crosslinking and Their In Vitro Evaluation

Hiraku Onishi , Kota Kume , Ken-ichi Koyama and Yoshiharu Machida
Department of Drug Delivery Research, Hoshi University, 2-4-41, Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.

ABSTRACT

The degree of deacetylation and molecular weight of carboxymethyl-chitin (CM) were manipulated using 10% (w/v) NaOH aqueous solution at 25°C and 5 M HCl aqueous solution at 40°C, respectively. The resultant CMs were characterized by 1H-NMR spectroscopy and size exclusion chromatography/multi-angle light scattering. The degree of deacetylation of 7 – 35% (mol/mol) and molecular weight of 43,000 – 449,000 were achieved. Nanoparticles were prepared using W/O emulsification and amide coupling. Nanoparticles with the size of less than 400 nm were obtained using CM with a high degree of deacetylation and low molecular weight, CM48-L. When the mixture of CM-mitomycin C conjugate and CM48-L underwent W/O emulsification and amide coupling, nanoparticles with the size of ca. 350 nm were obtained, and released mitomycin C fairly fast but gradually. CM with a high degree of deacetylation and low molecular weight was suggested to be useful for the production of CM nanoparticles.

Keywords:

Carboxymethyl-chitin nanoparticles, crosslinking, deacetylation, molecular weight, mitomycin C.