ABSTRACT
Objective: The aim of this study was to produce dense granules of tricalcium phosphate (β-TCP) and magnesium (Mg) substituted β-TCP, also known as β-TCMP (Mg/Ca=0.15 mol), in order to evaluate the impact of Mg incorporation on the physicochemical parameters and in vitro biocompatibility of this novel material. Material and Methods: The materials were characterized using X-ray diffraction (XRD), infrared spectroscopy (FTIR), electron microscopy and inductively coupled plasma (ICP). Biocompatibility was assayed according to ISO 10993-12:2007 and 7405:2008, by two different tests of cell survival and integrity (XTT and CVDE). Results: The XRD profile presented the main peaks of β-TCP (JCPDS 090169) and β-TCMP (JCPDS 130404). The characteristic absorption bands of TCP were also identified by FTIR. The ICP results of β-TCMP granules extract showed a precipitation of calcium and release of Mg into the culture medium. Regarding the cytotoxicity assays, β-TCMP dense granules did not significantly affect the mitochondrial activity and relative cell density in relation to β-TCP dense granules, despite the release of Mg from granules into the cell culture medium. Conclusion: β-TCMP granules were successfully produced and were able to release Mg into media without cytotoxicity, indicating the suitability of this promising material for further biological studies on its adequacy for bone therapy.
Subject(s)
Biocompatible Materials/toxicity , Calcium Phosphates/toxicity , Magnesium/toxicity , Analysis of Variance , Biocompatible Materials/pharmacokinetics , Bone Substitutes/pharmacokinetics , Bone Substitutes/toxicity , Calcium Phosphates/pharmacokinetics , Cell Proliferation/drug effects , Cell Survival/drug effects , Cells, Cultured/drug effects , Materials Testing , Microscopy, Electron, Scanning , Magnesium/pharmacokinetics , Osteoblasts/drug effects , Spectrum Analysis , Time Factors , Toxicity Tests , X-Ray DiffractionABSTRACT
This study investigated the mechanism by which anhydrous calcium phosphate [A-TAB] exhibits its sustained release matrix, via premixing of A-TAB [diluent] powder with different excipients, e.g. Avicel, sodium alginate and polyvinyl alcohol [PVA], to block entrapment sites if any, on the dissolution of theophylline from A-TAB tablets. Furthermore, the inclusion of other excipient [palmetic acid] to impart a more acid resistant character on the diluent/drug blend and thus assist in maintaining the matrix structure of A-TAB were also investigated. The rate and extent of drug dissolution were dependent on the order of mixing of A-TAB with the drug and excipient as well as the pH of the dissolution medium