The Study Of Preparation And Drug Loading Properties Of Inorganic/Organic Polymer Composite Drug Carriers

Through the perception of the external stimulus?such as pH value,temperature?,intelligent drug carriers can make corresponding physical or chemical changes,which can target drugs to focal area,avoid or reduce the impact on normal cells and improve the efficacy of drugs.The intelligent drug carriers include inorganic materials,organic polymer materials and composite materials.With large specific surface area,high drug loading,controllable size and morphology,and specific magnetic and optical properties,inorganic nanoparticles have many potential applications in drug carriers.The organic polymer materials have hard controllable molecular weight and poor drug loading,but they are sensitive to external environmental stimuli which is benefit for drug release.Intelligent composite drug carriers have good biocompatibility,high drug loading rate and intelligent drug release.Herein,the preparation,characterization and drug loading and release properties of several inorganic / organic polymer composites were investigated.1.Preparation,characterization and drug loading and release properties of the polyacrylic acid-graphene oxide-polyethylene glycol?PAA-g-GO-PEG?and?polyacrylic acid-poly N-isopropyl acrylamide?-graphene oxide polyethyleneglycols??PNIPAM-co-PAA?-g-GO-PEG?as drug carriers for Ibuprofen.?1?PEG was modified with GO and then grafted with PAA in situ,then PAA-g-GO-PEG nanocomposite were prepared.Compared with GO,the drug loading rate of PAA-g-GO-PEG composite reached as high as 209.59%.In hydrochloric acid buffer solution of pH=2.1,the release rate for GO and PAA-g-GO-PEG were 58.2% and 49.2%,respectively,while in pH=7.4 phosphate buffer solution,the release rate of GO and PAA-g-GO-PEG were 56.5%,42%,respectively.In alkaline conditions,the release rate of the two materials is smaller,indicating the materials are sensitive to pH.Under the same environment,the release rate of PAA-g-GO-PEG is smaller,which means that the sustained-release effect is better after grafting.?2?PEG was modified with GO and then copolymerized with PAA and PNIPAM in situ to prepare the?PNIPAM-co-PAA?-g-GO-PEG drug carrier.The drug loading rate of GO,PAA-g-GO-PEG,?PNIPAM-co-PAA?-g-GO-PEG were 190.5%,209.59% and 69.17%,respectively.The drug release rate for 24 h in hydrochloric acid buffer solution of pH=2.1 were 58.2%,49.2%,82.2%,which were higher than those in pH=7.4 phosphate buffer solution?56.5%,42%,54%?,indicating all the materials are sensitive to pH and the most sensitive one was?PNIPAM-co-PAA?-g-GO-PEG.The release experiments of?PNIPAM-co-PAA?-g-GO-PEG composite was performed at 25? and 37?,and the accumulative release rates were 54% and 58.1%.The release rate was faster at 37?,indicating that the material also has temperature sensitivity.2.Preparation,characterization and drug loading and release properties of poly?N-?acrylamide hollow mesoporous hydroxyapatite?PNIPAM-g-H-HAP?composite as drug carrier for Ibuprofen.?1?The hydroxyapatite microspheres were prepared by hydrothermal method using CaCO₃ microspheres as template,then etched with acetic acid etching to obtain hollow mesoporous hydroxyapatite.After grafting with PNIPAM,we finally got PNIPAM-g-H-HAP composite.?2?At 25?,the drug loading rate of PNIPAM-g-H-HAP was 62.2%,slightly higher than that before grafting,and higher than the drug loading rate of 56.2% at 37?.The release rate for 24 h in hydrochloric acid buffer solution of pH=7.4 and phosphate buffer solution of pH=2.1 were 35% and 41.4%.Comparing the drug release at 25? and at 37?,the release rate attained equilibrium within 5 hours of release at 37? with the release rate of 35%,it attained equilibrium after 7 h at 25? with the release rate of 31.7%,indicating the release is faster at 37? and the drug carrier is sensitive to temperature.