Characterization of the Chemistry of the Vancomycin-Containing PLGA-CaP Composite Coatings as Drug Carriers

This work performed a detailed characterization of the chemistry of the vancomycin-loaded PLGA-CaP composite coatings with different PLGA concentrations (5, 8, 10 wt %) on titanium implants for controlled sustained drug delivery. The lower CaP layer had a complex porous morphology with numerous branched pores and pore channels, and spheroidal elements on the surface, into which the antibiotic vancomycin was effectively loaded. The upper dense homogeneous PLGA layer partially penetrated the near-surface pores with drug. A gradient elemental composition (Ca, P, Ti, O, C) along the thickness and the homogeneous elemental distribution on the surface of all the vancomycin-loaded PLGA-CaP composite coatings were revealed. The vancomycin-loaded CaP coatings included strong P–O and P–OH bonds, while the composite vancomycin-loaded PLGA-CaP coatings were characterized by –C=O, –COO and C–O–C bonds. The formation of strong chemical bonds between the drug and the carrier components was confirmed by the alterations and broadening of the C1s, O1s, Ca2p and Ti2p peaks. This may be a favorable factor for efficient controlled sustained drug delivery.