| Along with scientific and technological advancement,polymer materials are beginning to be broadly applied in modern medical science, called biomedical polymers. There are currents that bio-degradable materials will be the mainstream in the development of biomedical polymers. Poly lactic acid (PLA) is a kind of excellent biomedical poly-ester, which has good biocompatible feature and can completely degradable into H2O and CO2. It started to be highly anticipated as a kind of promising degradable biomedical polymer when its degradability and the high safety of its degradable products had been confirmed. Currently, PLA are mainly applied in the fields of inner-fixing of fracture, tissue-repairing materials, surgical seam and drug delivery system, etc.PLA has been prepared by such methods as direct polycondensation, ring-opening polymerization and melt/solid polycondensation and so on. Ring-opening polymerization is commonly used to get high-molecular-weight PLA. In this paper, Lactide, which is synthesized through lactic acid condensation, was polymerized to form PLA by ring-opened of lactide.With this method, the synthesized polymericular weight was about 7.6x104.Hydroxyapatite(HA), the main mineral composition of bone,can form strong bone-bonding with natural bone and has been used extensively for biomedical applications and bone regeneration based on its high biocompatible, bioactive and osteoconductive properties.It was reported by researcher that the HA in the bone was mainly nano-Calcium-deficient carbonated HA (nano-dCHA). In this paper, we fabricated an anti-infection nano-Calcium-deficient carbonated HA (nano-dCHA) and PLA compounds, providing a new local drug delivery system (DDS). TBMC/ nano-dHA/PLA were prepared by an in-water drying method using a W/O/W emulsion. The comparisons between the two different compounds are also made. It showed that the average sizes of TBMC/nano-dHA/PLA were 57.805μm. The encapsulation efficiencies was 42.85% and the drug loading was 54.72%. It was also proved that TBMC/nano-dHA/PLA contained the characteristic peaks of TBMC,HA and PLA by IR. The thermal behavior by differential thermal analysis indicated that TBMC,HA and PLA mingled each other. The determination of its release rate in vitro revealed its release process of the drug according with the two-phase release pattern and it was in sustained release except an abrupt release in the initial times, this because the drugs were released rapidly from the surface. Then the release speed became slower and even stopped in certain stage. Its cumulative release percentage in vitro was over 65%. Influence of some factors such as the content of drug, the compound size and the pH value of release media on the drug-releasing performance of the compounds were studied. The result showed that the greater the content of the drug and the bigger the difference of drug concentration between in and out of the compound, and the more quickly the drug released. The smaller the compound size, the more quickly the drug released. In the alkali medium, the PLA degraded more quickly and the drug became more stable, resulting in faster release of drug.
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