Firstborn Microcrystallization Method To Prepare Artmisinin-Based Drugs-loaded Nanocapsules

Nanocapsule has become a new kind of drug delivery system with extensive potentialprospect of application. The methods of preparing nanocapsule and new applications of itare extended continually because of the development of nanotechnology and relativescience. And the attention paid by a great number of researchers has much to do with theadvantage of nanocapsules. Some drugs with the remarkable curative effect has a poorsolubility in body which is full filled by water, if coated by water-soluble wall materialthese drugs could be transported in body conveniently with the improved solubility in water.Some drugs with properties such as vapor ability and easily being oxidized could beimproved in stability after wrapped into nanocapsules. It is easy to take after being coated.Also nanocapsules have other outstanding advantages such as controlled-andsustained-release properties, subcellular size and target property. This article states thebeginning, the development, the preparation and the functional attribute of nanocapsulebased on the superiority of it, and seeks the new filed of application of it.There is large space for developing method of preparing nanocapsules though it has beenrich and perfected time after time. Lots of mature method such as emulsion polymerization,interfacial polymerization, coacervation-phase separation and the alternate absorption ofpolyelectrolyte were designed; in addition to that Professor Hong zong-guo provided himown original method called firstborn microcrystallization method. A certain medicine showdifferent solubility when dissolved in different solvent systems. If the drug concentrationwas get to be saturated the microcrystals would arise when increasing its concentratefurthermore. These microcrystals are wrapped rapidly by film material in solution system.Then the nanocapsules are produced by employing appropriate method. Theartemether-loaded nanocapsule was prepared by this new method in this paper.Although artemether is a powerful drug used to treat malaria, there are some drawbacksbecause of its natural property such as insolubility in water, faster metabolism and lowerbioavailability. In order to conquer these shortcomings, we prepared nanocapsulescontaining this drug by way of firstborn microcrystallization method. The producesobserved with transmission electron microscope (TEM) showed being well distributedspherical nanoparticles with mean diameter about100nm. In this test gelatin was chose asthe wall materials owing to its non-toxity, biocompatibility and biodegradability. As a resultthe preparation of this nanocapsule could possibly expend the clinical applicationof artemether. The second portion of the paper focuses on building a potent appliance which is going tobe employed to research the pharmacokinetics of nanocapsules. The test involves in a newfluorescent label given extensive attention which is CdTe Quantum Dots. The advantagesshowed by it may propose the possibility for monitoring behaviors of nanocapsules in vivo.In comparison with traditional organic dyes and fluorescent proteins, QDs have broadexcitation profiles and narrow symmetric emission peaks. Also they can be tuned to emit ina range of wavelengths by changing the nanoparticle size. Furthermore, their improvedbrightness, high resistance against photo bleaching and multicolor fluorescence emission isproperties superior to that of organic dyes. Artesunate was chose in the experiment. In orderto conquer its disadvantages, we prepared artesunate-loaded nanocapsules. To study thebehaviors of them about transportation, distribution and release, the work presentednanocapsules with ordered structural levels which are loaded fluorescent labels. The newtype of multi-layer nanocapsules takes quantum dots as its core. The coat of this capsuleconsists of gelatin and the mid-layer is formed from artesunate, the drug used to treatmalaria.The research of pharmacokinetics of nano-medicine decides whether the drug will beused in clinical. The traditional method often analyses the variation of blood concentrationin different time for the slowly-releasing drug delivery system with such small diameter. Itmust be a lot of work to do and seriously hurt the test animals. Under the help of imageinstruments in vivo we can supervise the real-time transportation and distribution ofnanocapsules when the QDs were imbedded into nanocapsules.By the firstborn microcrystallization method, we produced a new kind of multi-layernanocapsules，with their cores being QDs wrapped by Artesunate and coats consisted ofgelatins. The nanocapsules are about200nm in diameter, exhibited sphere-shaped orellipsoid particles and were well distributed with homogenous size. The obviousfluorescence of these capsules was observed. This provides potential possibility forreal-time supervision of drug movement in vivo.