Sustained Antibacterial Activity of Doxycycline-Loaded Poly( <scp>D</scp> , <scp>L</scp> -Lactide-Co-Glycolide) and Poly(ε-Caprolactone) Nanoparticles

Abstract

The mean particle size ranged from 230 to 360 nm, as measured by dynamic laser light scattering, and scanning-electron microscopy confirmed the spherical nature and smooth surface of the nanoparticles. Fourier transform infrared spectroscopy analysis of void nanoparticles, drug-loaded nanoparticles and native DXY indicated no interaction between the drug and polymer in the nanoparticle. Differential scanning calorimetry analysis of drug-loaded nanoparticles indicated a molecular level dispersion of DXY in the formulation. The antibacterial activity of native DXY and DXY-loaded nanoparticles were tested using a strain of Escherichia coli (DH5alpha) through growth inhibition and colony-counting method. The results indicated that DXY-loaded nanoparticles are more effective than native DXY due to the sustained release of DXY from nanoparticles in the E. coli strain.