Preparation and characterization of carvacrol loaded polyhydroxybutyrate nanoparticles by nanoprecipitation and dialysis methods.

In this investigation, preparation of carvacrol loaded polyhydroxybutyrate (PHB) nanoparticles was performed by nanoprecipitation and dialysis methods. PHB particles were obtained by nanoprecipitation method without and with low concentration of Tween 80 or pluronic as surfactant. Nano- and micro-sized particles were formed with trimodal distribution and large aggregates. Size and distribution of nanoparticles were decreased when concentration of Tween 80 was increased to 1% (v/v) in water as polar phase. PHB nanoparticles had narrow size (157 nm) with monomodal distribution. Nanoparticles, which were prepared by dialysis method had 140 nm in diameter with monomodal distribution. Carvacrol was used as a lipophilic drug and entrapped in optimized nanoparticles formulation by nanoprecipitation and dialysis methods. Entrapment efficacy was 21% and 11%, respectively. Morphology of PHB nanoparticles was spherical. The results of kinetic release study showed that carvacrol was released for at least 3 days. Release kinetic parameters showed a simple Fickian diffusion behavior for both formulations. Carvacrol loaded PHB nanoparticles had good dispersion into the agar medium and antimicrobial activity against Escherichia coli. This study describes the 1st work on loading of carvacrol into the PHB nanoparticles by nanoprecipitation and dialysis methods.