Preparation and Characterization of Self-Assembled Nanoparticles of Hyaluronic Acid-Deoxycholic Acid Conjugates

Xuemeng Dong,Chenguang Liu

doi:10.1155/2010/906936

Abstract

Novel amphiphilic biopolymers were synthesized using hyaluronic acid (HA) as a hydrophilic segment and deoxycholic acid (DOCA) as a hydrophobic segment by a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide mediated coupling reaction. The structural characteristics of the HA-DOCA conjugates were investigated usingH1NMR. Self-assembled nanoparticles were prepared based on HA-DOCA conjugates, and its characteristics were investigated using dynamic laser light scattering, transmission electron microscopy (TEM), and fluorescence spectroscopy. The mean diameter was about 293.5 nm with unimodal size distribution in distilled water. The TEM images revealed that the shape of HA-DOCA self-aggregates was spherical. The critical aggregation concentration (CAC) was in the range of 0.025–0.056 mg/mL. The partition equilibrium constant (Kv) of pyrene in self-aggregates solution was from1.45×104to3.64×104. The aggregation number of DOCA groups per hydrophobic microdomain, estimated by the fluorescence quenching method using cetylpyridinium chloride, increased with increasing degree of substitution.

Highlights

Polymeric amphiphiles derived from hydrophobically modified soluble polymers have recently attracted much attention because of their potential application in drug delivery systems [1,2,3]
For the synthesis of HD conjugates, we chemically coupled deoxycholic acid (DOCA)-NH2 to Hyaluronic acid (HA) with EDC as a crosslinker
Various HD conjugates were prepared by controlling the free mole ratios of DOCA-NH2 to HA

Summary

Introduction

Polymeric amphiphiles derived from hydrophobically modified soluble polymers have recently attracted much attention because of their potential application in drug delivery systems [1,2,3]. Such amphiphiles are able to spontaneously form micelles or nanoparticles via undergoing intra- and/or intermolecular association between hydrophobic moieties in aqueous environment. The hydrophobic parts form the core of the nanoparticles, which is a host system for various hydrophobic drugs, while the hydrophilic backbone forms corona or outer shells enwrapping the hydrophobic core This shell prevents the inactivation of the encapsulated drug molecules by decreasing the contact with the inactivating species in the aqueous (blood) phase [4,5,6]. It is expected that HA, hydrophobically modified with deoxycholic acid, will induce self-assembled aggregates

Experimental

Results and Discussion

H NHCOCH3 H OH n

Conclusion