Study On The Synthesis And Properties Of Composite Materials For Drug Loading Based On Halloysite

Halloysite with the nano tubular structure and large specific surface area,has the value of development and utilization,especially having a promising prospect in drug carrier.Based on the study of halloysite nanotubes modification,it is an effective method to improve drug loading properties of halloysite nanotubes.Adding sodium alginate,chitosan,hydroxypropyl methylcellulose phthalate and other organic matter into the halloysite nanotubes to compound cross-linking reaction to obtain compound drug loaded materials,can effectively improve the drug loading properties of halloysite.This experiment firstly explored the effects of different pretreatment and modification of halloysite nanotubes drug loading properties.Results indicate that the differences of modifiers' dosage and kinds have a small influence on halloysite nanotubes drug loading properties and the drug loading rate is all less than 10%,while the effect of pretreatment on halloysite nanotubes drug loading properties is obviously large and the pickling shows the best effect.After pickling,halloysite nanotubes' drug loading rate of metformin hydrochloride and loading capacity can reach 43.35%,2.13mg/g respectively and it is 4 times the effect of direct water washing.In this paper,the HNTs/SA/MH hydrochloride composite drug loaded microspheres were prepared by the emulsification solidified method.And the effect of preparation conditions on the encapsulation efficiency of metformin hydrochloride was explored by single variable method.The better processing condition of preparing composite microspheres with high encapsulation efficiency was: the curing temperature at 0 ?,SA: 1.0g/50 ml,HNTs: 2.0g/50 ml,MH: 4.0mg/ml and CaCl2:1.5g/50 ml.Besides,the study on sustained drug release effect of the composite drug loaded microspheres in solutions with different pH values was carried out.At different pH values,the composite microspheres had good pH sensitivity and sustained releaseeffect,and phosphate buffer can effectively release at pH=6.8 and the release degree reaches over 85.83% after 24 hours.In this experiment,the halloysite nanotubes / hydroxypropyl methylcellulose phthalate two formic acid ester / indomethacin composite materials were prepared by the composite coating method.The result shows that the optimize synthesis conditions of HNTs/IMC/HPMCP composite drug-loaded materials is HNTs:IMC : HPMCP=10:1:20(IMC= 0.025 g.Tableted HNTs/IMC/HPMCP composite drug-loaded materials have a good sustained-release performance and there is no drug release in the HCl solution with a pH of 1,while in the phosphate buffer solution(PBS)with a pH of 7.4and the NaOH solution with a pH of 13.Besides,the release rate in the NaOH solution with a pH of 13 was much smaller than it in the PBS,which indicates that the composite drug-loaded materials have a good property of pH sensitivity.Investigated by the infrared absorption spectra of composite drug-loaded materials and analyzing the characteristic peaks of each reagent,it was concluded that HPMCP,IMC,and HNTs were connected mainly in the form of physical absorption.