Construction And Characterization Of Nanoparticles Based On Polylactic Acid Glycolic Acid And Polyethylene Glycol

There are many obstacles in the traditional way of administration,which make it difficult to achieve the therapeutic effect and indirectly affect human health.The use of drug carriers to improve the drug delivery process is one of the most commonly used methods at present.Drug carriers can improve the bioavailability of drugs in the human body,drug sustained release,and reduce the side effects of drugs.Therefore,designing suitable drug carriers for different diseases has become a key problem to be solved.In this paper,this study selected the polylactic acid glycolic acid material with excellent biocompatibility and hydrophilic group polyethylene glycol as drug carrier system.The loading capacity of the drug carrier to the simvastatin of the hydrophobic drug was evaluated,and an ideal result was obtained in the experiment of blood compatibility of the composite particles.In the further study,the potential of materials used in cancer treatment was tested.Diagnosis and treatment is a hot spot in cancer treatment research.Using the above-mentioned carrier for cancer diagnosis and treatment,adriamycin and Fe₃O₄ are encapsulated at the same time,and the anti-tumor effect of composite particles and the effect of nuclear magnetic resonance imaging are evaluated.?1?Preparation and in vitro evaluation of drug carrier PLGA-PEG-PLGAThe treatment of osteoporosis requires long-term medication.The choice of the appropriate drug and the duration of the treatment can maximize the efficacy of the treatment of osteoporosis and minimize the potential side effect of long-term drug use.Simvastatin can effectively promote the formation of new bone and improve the efficacy of osteoporosis.However,the application of simvastain in osteoporosis is limited because of its low bioavailability The purpose of this study is to improve the bioavailability of simvastatin through a nano drug delivery system.Polymer PLGA-PEG-PLGA as a carrier of simvastatin was prepared by a ring-opening polymerization and loaded hydrophobic simvastatin with a load rate of 17%.In succession,release of simvastatin was studied and it was found that PLGA-PEG-PLGA showed a sustained release of simvastatin with the duration of 168 h,it can meet the requirement of long time administration for osteoporosis treatment.Through the transmission electron microscope,the particle size is homogeneous,the particle size of the shell is concentrated in the 40-100nm.The particle size of the composite nanoparticles loaded with the drug increases slightly in the 70-150nm,it has good specific surface area and the physical conditions required for efficient delivery.Moreover,hemolysis,morphology and accumulation of erythrocyte,prothrombin time,activated partial thromboplastin time and thrombelastogram were studied to evaluate the blood compatibility of the polymer.Composites loading drugs at the concentration under 1 mg/mL showed no harmful effect on hemolysis,morphology and accumulation of erythrocyte and cruor.Thus,PLGA-PEG-PLGA is considered to be a safe and effective drug carrier with potential clinic application.?2?Study of a medical agent carrier established by PLGA-PEGTumor has a high mortality rate,and worldwide cases of cancer are increasing year by year.Because of the physiological environment of tumor location,it is difficult to deliver antitumor drugs to the lesion.Chemotherapy is one of the most important ways to treat tumors.Traditional chemotherapeutic agents usually have strong side effects.The use of nano drug carrier can be used for passive targeting by using the special high permeability long retention effect?EPR?of tumor site.Therefore,drug carriers are of great importance in tumor delivery.Nuclear magnetic resonance imaging?MRI?is a widely used imaging method.It can be found in early stage,with high spatial resolution,good soft tissue contrast and penetration depth.The integration technology of diagnosis and treatment can effectively improve the efficiency of treatment,and adjust the treatment strategy through real-time imaging diagnosis and feedback effect.In the conclusion of the previous study,PLGA,PEG based drug carriers were found to have good load capacity.In further experiments,the nanoscale drug carrier system was constructed simultaneously with antitumor drugs and MRI contrast agents to achieve the effect of diagnosis and treatment.In this paper,PLGA-COOH was covalently linked to NH₂-PEG-COOH to obtain PLGA-PEG,and a good biocompatible PLGA-PEG was used to construct nano diagnostic vector.PLGA-PEG and Fe3O4 magnetic nanoparticles were successfully encapsulated by multiple emulsion method.The dynamic light scattering test results show that the particle size of composite particles is concentrated near 200nm,and the particle size required to achieve EPR effect can be achieved.The drug release experiment showed that the nano carrier had good sustained release effect on doxorubicin and could effectively control the release of the drug.Subsequently,the anti tumor effect of the diagnosis carrier was evaluated.The results of cell experiment showed that the drug carrier system could effectively inhibit the proliferation of MCF-7 cells,and still maintained over 50% of the inhibition efficiency at a low concentration of 75 ?g/mL.In the further experiments,the MRI effect of the composite particle was evaluated.In the in vitro imaging experiment,the composite particles showed an obvious enhancement of T2 signal,which could be effectively imaging.