Preparation Of PLA-co-Col/β-TCP Reservoir-type Carrier And Its Release Performance

In this paper,using polylactic acid(PLA) and collagen(Col) modified polylactic acid(PLA-co-Col) as matrix material,the principle and process of drug-carrier preparation were studied.Using solvent extraction/freeze-drying technology, combined with phase separation,through orthogonal experimental design to screen and optimize the main technical parameters,principle and fabrication process were discussed,and its performances were characterized by infrared spectroscopy(IR), X-ray diffraction instrument(XRD),MicroTester material testing machine, gravimetric method,scanning electron microscope(SEM) and three-dimensional video microscope.IR and XRD further confirmed a chemical reaction had taken place between PLA and Col,and the existence of chemical bonds,and obtained the PLA-co-Col composite materials.Porosity tested by gravimetric method was between 68%and 88%,volume/mass ratio(V_1.4-dioxane/m_PLA) played a leading role on porosity and frozen molding temperature and time had little effect on porosity. Mechanical bending experiments showed that the elastic modulus of material can reach to 139.77 MPa,enough to meet the requirements of the mechanical as a drug carrier material.SEM results showed that the cross-sectional displayed a kind of ruled, stretching the inner wall and outer wall to the middle layer,radial extension porous structure.The pore was a kind of connected structure,average pore size below 40μm.Orthogonal experiment result showed frozen forming time was the most minor factors in the three factors.Combining the results of drug release curve,The optimum process choice was 10%(volume/mass ratio),-70℃(frozen molding temperature)and 1 hour(frozen molding time).Weight loss rate of carriers was tested in vitro simulation biological environment. Using HCl-LVFX as a model drug,UV-visible spectrophotometric method,PBS solution as the release environment,studied the drug-carrier release performance with different volume/mass ratio,frozen molding temperature and time and drug loading dosage.Effects of physical addition and chemical modified were also discussed.In accordance with its own characteristics,combined with mathematical and theoretical models,the model has established a simple,practical drug release model and can described the features of various stages in this biodegradable polymer drug delivery carrier.Revealed the basic laws of the relationship between the structure and the release performance.