The Preparation Of Bioadhesive Sustained-Release Capsule Of Bletilla Striata Gum

Bioadhesive drug delivery systems (BDDS) defined as attachment of asynthetic or natural macromolecule to mucus and/or an epithelial surface.The ability to maintain a delievery system at a particular location for anextended period of time has great appeal for both local disease treatment aswell as systemic drug bioavailability. Many bioadhesives are made of either synthetic or natural polymers.Good bioadhesive should be no toxicity, good biocompatibility, easy to bemixed with drug, no effect on content determination of drug, easy to obtain.But few bioadhesives is coincidence with these demands. Bletilla striata is the tuber of torchids Bletilla striata, it's aconventional Chinese drug of hemostasia. Bletilla striata gum is extractedfrom Bletilla striata by water and deposited by ethanol. It's a kind ofmucopolysaccharide, it's white or brown dry powder, it's one of utilitycomponent of Bletilla striata. In treatment of peptic ulcer, Bletilla striatagum has a confirmed effect. But most of Bletilla striata gum used isextracted roughly or directly used as powder of Bletilla striata. Patientsswallow directly or doctors atomize the drug to the area of ulcer in thesupervition of endoscope. This manner of application is troublesome andthe quality of drug differs much. Additionally, Bletilla striata gum is a gooddrug carrier with many functions such as sustained release, local retention,self-degradation and no stimulation. In order to inspect the feasibility of Bletilla striata gum used asbioadhesive material and to better the conventional manner of applicationand to improve therapeutical effect of Bletilla striata gum for peptic ulcer,we have prepared bioadhesive and sustained-release capsule of Bletillastriata gum. Amoxiciliin is used as model drug. The capsule take theadvantage of pharmcology and characteristic of Bletilla striata gum,andcombine the clearance of amoxicillin to Helicobacter pylori.Aspects suchas adhesive properties of Bletilla striata gum in vitro,the preparationtechniques of the capsule,the adhesive properties of capsule in vitro and invivo,the drug release of capsule in vitro and in vivo were investigated. The first part of dissertation is about the extraction of Bletilla striatagum and quality control.We use water to extract and deposite byethanol,the extraction technique is optimized by an orthogonal experimentdesign.The optimal extraction technique: Bletilla striata is shattered intoparticles,and extracted by distilled water 5 times at 60-70℃,half an houreach time.The extracted fluid is deposited by 95% ethanol, the depositor iscollected and aired to dry.The content of Bletilla striata gum that weextracted is beyond 80%. The second part is about the investigation of bioadhesive properties ofBletilla striata gum in vitro. We use self-made device to determine the shearstress of Bletilla striata gum and detachment with stomach tissue and theremaining percentage in the stomach tissue. The result is contrasted withcarbopol which is common bioadhesive material.The shear stress of Bletillastriata gum is bigger than carbopol,and the difference is significant.But thedetachment and remaining percentage with stomach tissue is similar tocarbopol,and there is no significant difference.These results confirmed thatBletilla striata gum posses good bioadhesive property. The third part is the preparation of bioadhesive and sustained-releasecapsule of Bletilla striata gum and assessment in vitro.We prepared thecapsule by wet granulation,using Bletilla striata gum as bioadhesivematerial and amoxicillin as model drug.The formulation is optimized by anorthogonal experiment design according to the drug release andbioadhesive properties in vitro.The optimal formulation:the ratio of Bletillastriata gum and amoxillin is 3∶1,the diameter of granules is 0.92mm,thebinder is 10% PVP ethanol solution. In vitro experiment, dissolution behavior and bioadhesive properties ofthe capsule were studied.At the same time,we studied the factors that hadeffects on the dissolution behavior and bioadhesive properties.In 0.1mol/Lh...