Evaluation of Drug-Loading Ability of Poly(Lactic Acid)/Hydroxyapatite Core–Shell Particles

Poly(lactic acid)/hydroxyapatite (PLA/HAp) core–shell particles are prepared using the emulsification method. These particles are safe for living organisms because they are composed of biodegradable polymers and biocompatible ceramics. These particles are approximately 50–100 nm in size, and their hydrophobic substance loading can be controlled. Hence, PLA/HAp core–shell particles are expected to be used as drug delivery carriers for hydrophobic drugs. In this work, PLA/HAp core–shell particles with a loading of vitamin K1 were prepared, and their drug-loading ability was evaluated. The particles were 40–80 nm in diameter with a PLA core and a HAp shell. The particle size increased with an increase in the vitamin K1 loading. The drug-loading capacity (LC) value of the particles, an indicator of their drug-loading ability, was approximately 250%, which is higher than the previously reported values. The amount of vitamin K1 released from the particles increased as the pH of the soaking solution decreased because the HAp shell easily dissolved under the acidic conditions. The PLA/HAp particles prepared in this work were found to be promising candidates for drug delivery carriers because of their excellent drug-loading ability and pH sensitivity.