Preparation Of Hollow Mesoporous Wollastonite Drug Loading Microspheres And Their Application In Drug Loading And Sustained Release

In recent years,in the wake of large amount of anti-cancer drugs thriving,corresponding drugs are endeavoring to the treatment of cancers which has been regarded as an incurable disease.However,most of the anti-cancer drugs currently in clinical use suffer from side effects,like physical damage caused by release in the human body,and repeated administration of drugs that degrade drug performance and increase patient pain.Accordingly,drug delivery and sustained release research has attracted the attention of researchers.For the drug carrier material itself,in addition to its material composition and morphological structure,the design of a structure with high specific surface area at the microscopic level is also a key factor affecting its drug delivery and release capability.Compared with other inorganic materials such as silica,metal oxides,noble metals and carbon materials,Wollastonite,i.e.calcium silicate based material,especially nanostructured calcium silicate materials have high biocompatibility,bioactivity and degradability,and have great potential for application in the biomedical field,while their high specific surface area and nano-pore structure make wollastonite materials have excellent drug-carrying capacity,drug release function and It has a broad application prospect.Calcium silicate based drug delivery system is equipped with long drug release time,which allowed to significantly prolong the therapeutic effect of drugs and avoid causing secondary damage to patients during repeated drug administration.Another striking advantage of calcium silicate based drug delivery system is its excellent p H-responsive drug release properties,which can be used as an ideal platform for targeted drug delivery to achieve controlled targeted drug delivery behavior in some special complex p H environments in vivo.Starting from the limitations of current research on calcium silicate based materials of drug loading,for instance,unstable morphological structures and growth structures favoring irregular shapes such as flakes and filaments,while materials with spherical structures present a homogeneous state when ingested or injected into the body as drug carriers,which is more favorable for drug delivery,this paper therefore propose to prepare hollow mesoporous wollastonite drug-carrying microspheres by the template method in order to design a homogeneous hollow spherical wollastonite drug carrier with a p H-responsive function and a stable structure.The specific work was divided into two parts as follows.1.Firstly,three different templates of CPS spheres,calcium carbonate spheres and mesoporous silica were respectively employed to construct hollow wollastonite microspheres and hollow double-shell layer mesoporous wollastonite microspheres.Following the experimental operation of template removal,the morphological structures of the samples were characterized by XRD,SEM and TEM tests,and it was found that when CPS was used as a template,after the removal of CPS by calcination,the calcium carbonate spheres are difficult to form hollow structure after growing calcium silicate as a template.In contrast,hollow silica microspheres as a template can not only maintain a regular spherical structure,the synthesis method is simple and environmentally friendly,and the physical adsorption test results surface its specific surface area can also be maintained at a high level,there is a large number of mesoporous structures exist,which is conducive to drug loading and sustained release studies.In doing so,we successfully synthesized a hollow mesoporous SiO₂@Ca SiO₃double-shell layer drug-loaded microspheres.2.Leveraging on the successful synthesis of hollow mesoporous SiO₂@Ca SiO₃double-shell layer drug-loaded microspheres,we combined them with the anticancer drug Adriamycin to form a drug loading system.Then MTT method was used to test the cytotoxicity of the carrier and the results revealed that the apoptosis rate was about 10%after 24 h of incubation with He La cells,indicating that the material is biocompatible and adequate to be used as a drug carrier for the research.Subsequently,We examined the drug loading capacity of the carriers by UV spectrophotometry and it was demonstrated that the carrier exhibited a high drug encapsulation rate of 95.6%at low drug concentrations,and the drug loading capacity was able to be maintained at 0.692 mg Dox/mg SiO₂@Ca SiO₃ when the ratio of drug amount to carrier reached 1:1 with increasing drug concentration.As a biocompatible drug load and sustained-release material,it possesses immense potential for application.At last,we established two environments with p H 7.4 and 4.5 under different p H conditions to perform in vitro drug retardation experiments on the carriers after drug loading.The outcomes showed that SiO₂@Ca SiO₃ hollow double-shell layer microspheres had a remarkable responsiveness to low pH conditions,and the drug release rate and drug release amount were enhanced clearly compared with the neutral environment.The release time of the carrier material was up to 120 h in varying circumstances.In this paper,we successfully designed a kind of hollow mesoporous SiO₂@Ca SiO₃ double shell drug loading microspheres with regular morphology and p H response performance,which has excellent drug loading and sustained-release ability,and has far-reaching significance in the research of drug loading system.