The Preparation Of The Rhubarb Colon-Targeting Tablets

The technique of drug transfer is used in Oral Colon-targeting Drug Delivery System(OCDDS), in which drugs does not release in the upper digestive tract with oral administration butbegins to collapse or erode when they arrive at ileocecus and act medicinally at colon. The rhubarbcolon-targeting tablets were prepared with rhubarb which is effective for colonitis. According to thegastrointestinal tract pH value, the experiment prepared pH-dependent colon-targeting preparationwith rhubarb extraction. The experiment is divided into extraction of effective component and thepreparation of Colon-targeting tablets.The optimum technologies of hydrolisis extraction were set up with the natures of theanthraquinone, the optimum technologies: 56℃, 15% sulfuric acid: chloroform (1:5). Theextracting product was separated with alkali dissolution and acid precipitation, so the content of theemodin is 40.01% in rhubarb extraction, and its content is about 200 times more than the content incrude rhubarb.The content and drug release in vitro was determined by HPLC, the chromatographyconditions: Alltech ODS C₈ column, methyl alcohol: 0.05%phosphoric acid (85:15), speed of flow:1.0mL/min,λ: 254nm. The concentrations of emodin and peak areas were good linear relationshipin simulated gastric fluid, simulated intestinal fluid and Simulated colonic fluid. The data usingthe method was accurate and reproducible.The optimum formulation of 100 tablet cores was determined, the optimum formulation:rhubarb extraction: 2.5g, starch: 6g, PEG4000: 3g, lactose: 8.1g, magnesium stearate: 0.2g,CMS-Na: 0.2g.The tablet cores were coated by acrylicresinâ…¢. The optimum extra weighing of coating was20% through experiments, and the drug didn't release in simulated gastric fluid in 1 hour, didn'trelease in simulated intestinal fluid in 3 hours, the release rate of the drug is more than 75% in simulated colonic fluid in 1 hour. The optimum coating formulation: ethyl alcohol: 400mL,acrylicresinâ…¢: 24g, Neighbouring diethylphthalate: 8g, twain-80: 2g, castor oil: 3g.In addition, quality standards of the rhubarb colon-targeting tablets were studied, such asfigure, discrimination, weight diversity, content assaying, release of the tablets, and the stability ofthe rhubarb colon-targeting tablets. The results suggested that each inspection be in keeping withthe Chinese pharmacopoeia (2005).