The Preparation And Drug Loading Research Of Chitosan/Montmorillonite And Chitosan/Iron Oxide Composite Microspheres

Chitosan has excellent biocompatibility, biodegradability, non-toxicity, beingprocoagulant, the molecular chain possess a large number of reactive amino and hydroxylgroups,all these properties make chiton a unique matrix for the drug delivery the system.There is a variety of formulations for the drug delivery system, and as one ofthem,microspheres have many advantages,such as having a controlled release, locally targetedrelease, reduced drug toxicity, improved drug stability, it is a very effective form ofadministration drug. Conventional microspheres tend to focus on the preparation between thesame or different kinds of polymers to form microspheres in a certain way, and there is lack ofresearch to combine the inorganic nano-materials with organic polymer materials to formsustained released microspheres. Particularlly,the the research about combining layeredsilicate montmorillonite clay,which has excellent performance, with polysaccharides toprepare composite drug- loaded microspheres is rarely reported. In addition, the combinationof inorganic iron oxide nanoparticles with chitosan to form composite magnetic microspheresis also a promising drug targeting system. This article prepared by two organic / inorganicparticle delivery system, namely chitosan / montmorillonite and chitosan / iron oxidecomposite microspheres.In this study, we use liquid paraffin as oil phase, Span 80 as emulsifier, glutaraldehyde tocrosslink chitosan,the microspheres show good spherical morphology, chitosan microspheresprepared by this method is relatively easy to cohere with each other in some degree, and thedegree of being cohesive differs in different conditions. We used a orthogonal experimet toinvestigate the influence of different factors on the microspheres’ size and uniformity, theconclusion is that glutaraldehyde concentration matters the most,followed sequence ischitosan concentration,Span 80 dosage and oil phase volume ratio is the least importantfactor.The optimal condition is chitosan at a concentration of 10 mg / ml, oil / water volumeratio= 3: 1, glutaraldehyde concentration is 25% wt, Span 80 content is1 ml.On the basis of the previous orthogonal experiments,we prepare aspirin loaded CS /MMT composite microspheres, it has a spherical morphology with the particle size from 1 ~10um.When Asp / CS = 1: 1, MMT: CS = 1 : 1, the drug loading content is 81.63 mg / g. Withincreasing MMT content, the drug loading content and encapsulation efficiency of themicrospheres is improved.However,with increasing levels of aspirin, the drug contentincreases while the encapsulation efficiency decreases. The adding of montmorilloniteimproved the burst effect of CS microspheres, extends its release time.When Asp / CS = 1: 1,MMT: CS = 1: 1, and the cumulative release time reaches 700 min, its cumulative release rateis only 35%, indicating that the microspheres have a good release effect,besides, thedrug-loaded microspheres show a certain p H-sensitive property.This study prepared Largazole-loaded CS/MMT microspheres and used mice model withautoimmune defects for the experiment.The assessment of animal experiment showed thatLargazole-loaded CS/MMT microspheres presented a good therapeutic effect,the Largazolehad excellent biological activity over 7-day periodThis study compared the difference bewteen the high voltage electrostatic spray methodprepared microspheres and the crosslinking emulsion method ones. We found thathigh-voltage electrostatic spray method prepared microsphers have a size of about 100 um andare well dispersed.When heated in the 30 ~ 800 ℃ decomposition temperature, theremaining chitosan mass fraction of 10%, while the emulsion crosslinking method is18.5%.Through the hysteresis loop, resulting electrostatic spray method prepared magneticmicrospheres have a stronger magnetism than emulsion method, the saturation magnetizationof the former is 30 emu / g, while the latter is 26 emu / g.The result shows both types ofmicrospheres have zero coercivity force,indicating that they are very responsive to.a certainexternal magnetic field.