Preparation And Characterization Of Colon Targeting Eudragit S100Nanoparticles

Oral colon drug delivery system（OCDDS）is a one of the hot research area recently,which focus on oral administration agents could release drug in the colon. Firstly,because of lack of exercise and the drug delivery is relatively slow in the colon, whichwill provide a stable environment and strong local absorption. Secondly, drug can bedissoluted when reaches the human ileocecal portion, drug can be deliveryed into thelesion directly, increase the efficacy, reduce the dose, avoid the first pass effect, enhancethe therapeutic specificity, reduce the systemic adverse reactions and improve patientmedication compliance.Eudragit is a product name of the synthesis of methyl acrylic acid copolymer andmethyl acrylate copolymer. The S series are mainly used for delay release, with pHtrigger gastrointestinal targeted, can be used in the colonic drug delivery, protection ofacid sensitive drug, avoiding the stomach hurt.At present, polymer nanoparticles is widely used in drug delivery due to its slowcontrolled release, prolong drug curative effect. But most of the nano drug carrier hasonly passive targeting by osmosis-keep. Lectin is a protein capable of binding glycosylprotein, its most significant characteristic is to have the ability of a specific combinationof specific glycosylation. Using the carbohydrate-binding specificity characteristic ofthe lectin, coupling lectin to the surface of the nanoparticles could constitute areceptor-ligand-mediated actively targeted nanoparticle drug delivery system.In this experiment, the carrier material is S100, using lectin and S100to prepareLectin-S100conjugates by the acylation reaction. According to the infrared spectra andX-ray diffraction, lectins are verified bonded to S100successfully. The optimumconditions of Lectin-S100conjugates were that S100is500mg, Lectin is2.0mg, EDCis200mmol, the reaction temperature is35℃and the reaction time is14h.5-ASA/Lectin-S100nanoparticles were prepared by chemical precipitation method.The optimum conditions of5-ASA/Lectin-S100nanoparticles were that the pH value ofthe solution was controlled as5.0, the mass ration of5-ASA/S100was1:10. Theobtained nanoparticles were spherical in shape with good stability. Infraredspectroscopy, X-ray diffraction confirmed the linkage of the polymer.In vitro release pattern show that the5-ASA/Lectin-S100nanoparticles appeared tohave an initial burst effect and followed by a slow, sustained drug release. Moreover, the nanoparticles have certain colon-specific drug release characteristic, according to therelease pattern in stimulated intestinal medium.According to the literature, many hydrophobic drugs with significantpharmacological activities is diffcult to make drug formulation because of the lowsolubility. The blood drug concentration is hard to meet the treatment of requirementbecause of its low solubility in water. Select the hydrophobic drug Indomethacin asmodel drug, using cyclodextrin to enhance solubilization, exploring the drug loaded andin vitro release characteristics of IDM/β-CD/S100. The optimum conditions ofIDM/β-CD/S100nanoparticles were that the pH value of the solution was controlled as5.0, the mass ration of IDM/S100was1:10. The drug loading of hydrophobic drug isobvious increasing of the nanoparticles, the in vitro release test shows that they aresatisfy the basic demands of oral colon-specific drug.