Adsorption and release studies of sodium ampicillin from hydroxyapatite and glass-reinforced hydroxyapatite composites

As a potential therapy for periodontitis, sodium ampicillin, a broad spectr um antibiotic, was adsorbed onto hydroxyapatite (HA) and glass-reinforced h ydroxyaptite (GR-HA) composites, and was subsequently released in vitro. Th e sodium ampicillin, was adsorbed more on HA compared to the GR-IIA composi tes. X ray diffraction (XRD) and Rietveld analysis were used to identify an d quantify the levels of HA and beta -tricalcium phosphate (beta -TCP) in t he microstructure of the GR-HA composites, Lattice parameters changes were observed for the beta -TCP phase dependant on the amount of glass added. Th e release kinetics were shown to be divided into three stages, the first of which where a large amount of sodium ampicillin is released, followed by a slower release rate and then a final stage where the release amount approa ches zero, until no more sodium ampicillin was present. X-ray photoelectron spectroscopy (XPS) studies were carried out in order to ensure that the en tire antibiotic adsorbed onto the materials had been released. These kineti cs studies have indicated the possibility of using these materials as possi ble carriers for drug delivery. (C) 2001 Elsevier Science Ltd. All rights r eserved.