Bioactive calcium phosphate (CaP) coatings on commercially pure Ti deposited by the hybrid ultrasound-assisted micro-arc oxidation (UMAOH) method have been studied as drug carriers due to their biocompatibility and ability to sustain drug release. The dip-coating technology for the subsequent polymerization with PLGA (50:50) of the hybrid CaP coating for drug-carrying purposes has been optimized for more sustained release. In this work, the release kinetics of vancomycin (VMN), and interferon α-2b (IFN) from unmodified and modified with PLGA CaP coatings together with their structure, mechanical properties and bioactivity were investigated.

It was found that VMN from unmodified CaP coatings were almost completely released into an isotonic solution after 6 hours of immersion, with a burst release of 75% in the first 10 minutes. IFN release, however, showed a complex "wave-like" dynamics, with the maximum release after 1 and 12 hours of exposure. The complex dynamics of IFN release were associated with the change in the processes of desorption from the surface of the CaP drug carrier followed by precipitation of biological molecules from the solution onto the CaP surface.

In case of the PLGA/CaP composite after dip-coating and impregnation with VMN, a monotonous logarithmic dynamics of drug release for 7 days have been observed. For PLGA/CaP carriers impregnated with IFN, a complex "wavelike" dynamics of drug release was repeatedly found, which was similar to the unmodified CaP coatings impregnated by this drug. The dip coating step significantly prolonged the IFN drug release up to 14 days. The antimicrobial activity and viability tests in vitro confirmed the high potential of the PLGA/CaP drug carrying systems for further investigation and hopefully clinical use.