Biodegradable nanoparticles of methoxy poly(ethylene glycol)-b-poly( d, l-lactide)/methoxy poly(ethylene glycol)- b-poly(ϵ-caprolactone) blends for drug delivery

Yodthong Baimark,Yaowalak Srisuwan

doi:10.1186/1556-276x-7-271

Abstract

The effects of blend weight ratio and polyester block length of methoxy poly(ethylene glycol)-b-poly( d, l-lactide) (MPEG- b-PDLL)/methoxy poly(ethylene glycol)- b-poly(ϵ-caprolactone) (MPEG- b-PCL) blends on nanoparticle characteristics and drug release behaviors were evaluated. The blend nanoparticles were prepared by nanoprecipitation method for controlled release of a poorly water-soluble model drug, indomethacin. The drug-loaded nanoparticles were nearly spherical in shape. The particle size and drug loading efficiency slightly decreased with increasing MPEG- b-PCL blend weight ratio. Two distinct thermal decomposition steps from thermogravimetric analysis suggested different blend weight ratios. Thermal transition changes from differential scanning calorimetry revealed miscible blending between MPEG- b-PDLL and MPEG- b-PCL in an amorphous phase. An in vitro drug release study demonstrated that the drug release behaviors depended upon the PDLL block length and the blend weight ratios but not on PCL block length.

Highlights

In the past few decades, biodegradable and biocompatible nanoparticles of methoxy poly(ethylene glycol)-bpoly(D,L-lactide) (MPEG-b-PDLL) and methoxy poly-b-poly(E-caprolactone) (MPEG-b-PCL) amphiphilic diblock copolymers have shown potential as controlled-release drug delivery carriers because of the small size of their nanoparticles, which improves circulation time in the body and decreases the administration frequency when compared to microparticles which are rapidly cleared by the reticuloendothelial tissue [1,2]
Morphology and size Morphology of the blend nanoparticles was investigated by transmission electron microscopy (TEM), an example of which is shown in Figure 1 for the MPEG-b-PDLL30K/MPEG-b-PCL30K blend nanoparticles
The hydrophobic core of the PDLL/PCL blocks is surrounded by the water-soluble polar groups of the MPEG blocks that extend into the aqueous medium to prevent nanoparticle aggregation

Summary

Introduction

In the past few decades, biodegradable and biocompatible nanoparticles of methoxy poly(ethylene glycol)-bpoly(D,L-lactide) (MPEG-b-PDLL) and methoxy poly (ethylene glycol)-b-poly(E-caprolactone) (MPEG-b-PCL) amphiphilic diblock copolymers have shown potential as controlled-release drug delivery carriers because of the small size of their nanoparticles, which improves circulation time in the body and decreases the administration frequency when compared to microparticles which are rapidly cleared by the reticuloendothelial tissue [1,2]. Much attention was paid to the drug-loaded nanoparticles of these amphiphilic diblock copolymers with different types of chemical compositions and lengths of polymer blocks used [8,9,10,11]. The drug release rate from poly(L-lactide)/PCL blend nanoparticles prepared from the nanoprecipitation method using poloxamer 188 as the surfactant has been adjusted by varying the blend weight ratios [16]

Methods

Results

Conclusion