Poly(lactic acid)/hydroxyapatite (PLA/HAp) core-shell particles loaded with hydrophobic drugs were fabricated through a modified surfactant-free emulsification method. The core-shell particles are expected to encapsulate hydrophobic drugs, whose clinical use is often hampered because of their poor water solubility. In this study, phylloquinone, a drug that mediates the gamma carboxylation of glutamyl residues, was used as a model hydrophobic drug. Oil-in-water emulsions were prepared using an organic phase composed of dissolved PLA with various amounts of phylloquinone and an aqueous phase composed of calcium acetate and diammonium hydrogen phosphate. The obtained suspension exhibited a yellow color, indicating that the particles successfully incorporated phylloquinone. Scanning electron microscopy and X-ray diffraction analyses revealed these particles to be PLA/HAp core-shell composites loaded with phylloquinone, approximately 100-500 nm in diameter. The particle diameters were affected by the amount of loaded phylloquinone; excess phylloquinone causes encapsulation failure. The drug release behavior of the phylloquinone-loaded PLA/HAp particles was examined via UV detection. The phylloquinone release profile showed a sustained release from the PLA/HAp core-shell particles over a ten days period. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.