Preparation And Release Behavior Of Bioresorbable Micelles From Polylactide-Poly(Ethylene Glycol)-Polylactide Block Copolymers | Posted on:2013-06-09 | Degree:Master | Type:Thesis | Country:China | Candidate:X Qi | Full Text:PDF | GTID:2231330395950109 | Subject:Materials science | Abstract/Summary: | PDF Full Text Request | With the development of biology and medicine, bioresorbable polymers have been widely used in drug delivery systems. They have been attracting growing attention due to their outstanding physical, chemical and biological properties which can be easily controlled and adjusted by polymer chemistry. Nano micelles prepared from bioresorbable polylactide and poly-(ethylene glycol) block copolymers now become more and more popular among all drug delivery system.PLA-PEG triblock copolymers with different molecules weights were synthesized from lactide and dihydroxyl PEG. The resulting triblock copolymer were characterized by1H NMR, XRD and DSC. Copolymer micelles were prepared by direct dissolution or solvent evaporation followed by membrane hydration methods. Paclitaxel (PTX) was taken as a model drug to evaluate the potential of PLA-PEG-PLA nano micelle as carrier of hydrophobic drug. The sizes and structures of micelles were determined by dynamic light scattering (DLS), transmission electron microscope (TEM) and scanning electron microscope (SEM). Drug encapsulation efficiency (EE), loading content (LC) of micelles and release behavior were evaluated by high-performance liquid chromatography (HPLC). Various parameters such as copolymer composition, drug feed, micelle preparation and lyophilization process were considered. The cytotoxicity of blank micelles and drug loaded micelles was evaluated by MTT method.In conclusion, both direct dissolution and solvent evaporation/membrane hydration methods fulfill the requirements for sustained delivery of PTX. Direct dissolution presents the advantages of simplicity without organic solvent. The release rate has been enhanced after micelles lyophilization of micelles. Similar C6glioma dose-effect curves were obtained for PTX loaded micelles by direct dissolution and free PTX. Higher EE and LC values were obtained for micelles by solvent evaporation which has potential of long circulating use. MTT results showed that the copolymers and the preparation methods present no cytotoxicity. | Keywords/Search Tags: | polylactide, poly(ethylene glycol), micelle, paclitaxel, drug release | PDF Full Text Request | Related items |
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