Effects of process parameters on the colloidal properties of polycaprolactone microparticles prepared by double emulsion like process

Preparation of polycaprolactone (PCL) based microparticles by double emulsion solvent diffusion like process was studied in this work. The double emulsion was prepared in two steps. In first step, the inner aqueous phase (W-1) was added to dichloromethane (DCM) solution containing PCL and homogenized to form primary emulsion (W-1/O). In the second step, the primary emulsion (W-1/O) was emulsified with the outer aqueous phase (W-2) containing polyvinyl alcohol (PVA) as stabilizer using ultra-turrax at a specific speed and time in order to achieve the double emulsion (W-1/O/W-2). Effects of various parameters such as stirring time and speed, polymer amount and the volume fraction of each phase on hydrodynamic particle size, size distribution and zeta potential were investigated. As a general tendency, zeta potential of all prepared particles was found to be constant irrespective of investigated parameter. Whereas, the increase in polymer amount leads to large particles size and lowest sizes were obtained when high stirring speed was used during the second emulsification step. (C) 2014 Published by Elsevier B.V.