Application Of Polyhydroxyalkanoates Nanoparticles As Intracellular Sustained Drug-Release Vectors

In this study, Polyhydroxybutyrate (PHB), copolyesters of 3-hydroxybutyrate and 3-hydroxyhexanoate (PHBHHx), and polylactic acid (PLA) were prepared into nanoparticles with average sizes of 160, 250 and 150 nm, respectively. A lipid soluble colorant rhodamine B isothiocyanate (RBITC) was employed to study drug release behaviors from these nanoparticles. A high RBITC drug loading efficiency of over 75% was achieved with all PHA nanoparticles prepared. Macrophage endocytosis led to an intracellular RBITC drug sustained release over a period of at least 20 days for PHB and PHBHHx nanoparticles, while PLA nanoparticles and free drug lasted only 15 days and a week, respectively. Polymer properties and particle sizes showed little effect on drug release behavior. This study showed for the first time that PHB and PHBHHx can be used effectively to achieve intracellular drug control releases.