Preparation and characteristic of lactose-oleoylchitosan and the application of its self-aggregates as drug delivery system

Amphiphilic polymers lactose-oleoylchitosan (Lac-OCH) with different degree of substitution (DS) of lactose were prepared. The chemical structure of the new chitosan derivative was tested and verified. The rheological features including solubility and viscosity of Lac-OCH were investigated. The introduction of hydrophilic group lactose could improve the solubility of the polymer and Lac-OCH was soluble in acetic acid solution under pH 7.0. The viscosity of Lac-OCH decreased a little along with the increasing of DS of lactose. Lac-OCH with high DS, middle DS, and low DS of lactose possessed small critical aggregation concentration value, and the critical aggregation concentration value rised along with the increasing of DS of lactose. However, the affect was not obvious. In brief, the CAC values were 0.0325, 0.0340, and 0.0344 mg/mL corresponding to the samples of low DS, middle DS, and high DS. Lac-OCH, obtained by hydrophilic modified using lactose, could also form self-assembled nanoparticles by oil/water (O/W) emulsification method comparing with OCH. The Lac-OCH nanoparticles showed dense, axiolitic texture, and the average diameter was approximate 200 nm. The sustained-release characteristics of Lac-OCH nanoparticles were studied using Doxorubicin as model drug. The results revealed the promising potential of amphiphilic Lac-OCH as drug carrier. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 3359-3367, 2011