藥劑學(xué)實(shí)驗(yàn)教案-華西醫(yī)科大學(xué)doc-資料下載頁(yè)
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【正文】 當(dāng)片劑破碎時(shí)，活動(dòng)橫桿的彈簧停止加壓。儀器刻度標(biāo)尺上所指示的壓力即為硬度。測(cè)3~6片，取平均值。四、實(shí)驗(yàn)結(jié)果與討論外觀片重差異崩解時(shí)間硬度（kg）結(jié)論五、思考題1．試分析乙酰水楊酸片處方中各輔料成分的作用。2．配制10％淀粉漿，為何先將淀粉加熱，稍冷后再使用？ Experiment Six Preparation of Acetylsalicylic Acid Tablets1. Purpose To grasp the general technique of WetGranulation Method To grasp the use of singlepunch press machine and the quality tests of Tablets2. Guidance of experimentTablets are solid preparations each containing a single dose of one or more active ingredients and obtained by pressing uniform volumes of particles. Tablets are usually prepared with the aid of suitable pharmaceutical excipients and usually right, circular solid cylinders or other erose shape. They are intend for oral administration or external use and are the most monly prescrible dosage form .The reason for this popularity is that tablets offer a convenient form of drug administration, provide dosage uniformity from tablet to tablet, are stable over extended, and low cost .The methods for the preparation of pressed tablets contain Granulation method, crystal directpression and powder directpression . The Granulation method prises WetGranulation Method and DryGranulation Method. Following is WetGranulation Method process:Active ingredients + excipents (fillers or absorbents, disintegrants ) homogeneous blending mixed powder moistening agents or adhesives damp mass screening wet granules drying—dry granules ( determine the content , water ) screening dry granules lubricants and external disintegrants homogeneous blending tableting by pression Each steps in this series of process affects tablet quality .The active ingredients and excipients should ply with the requirements . Especially when active ingredient is hardly soluble .The particle size of drug should be small enough to ensure the homogeneous blending with excipients and qualified dissolution of tablets. The blending homogeneity of active ingredients and excipients is related to operations .When potent substances are mixed with a large amount of diluent , the Geometric Dilution Method is employed to ensure the uniform distribution of the potent drug ,but the range of content is great . There is another method, Solvent Dilution Method , that is to dissolve the small quantity drug with proper solvent at first , then add other ponents and blend ( often have a well blending and the range of the content is narrow ) Preparation of granules is very important for tablets. When apply WetGranulation Method to mak graceful granules ,the corresponding adhesives or moistening agents should be chosen depending upon the nature of active ingredients . To make a qualified damp mass , the amount of adhesives or moistening agents should be controlled . (Agglomeration when holding, dispersing by slight pressure and can’t stick to hand ) . The granules made by sieving should be integrate. A small amount of little particles are permissible, but if little particles are too much, it demonstrates the adhesives is scarce 。 if appearance is strip shape , it indicates the adhesives is excess .After drying with either condition , the granules is too loose or too hard , neither plies with the standards nor produce good tablets . The size of granules which based on the size of tablets is decided by the meshes of screens .Generally —16 screens are employed for large tablets ( — ) , —20 screens are used for small tablets (less than ) .The granules should be fine and rounded .Drying and Granulation process : As soon as possible to make the prepared wet granules dry at the temperature 40—60 oC. Be careful not to place too much particles at one time, keep the layer thin lest the drug is destructed after long –time drying . The dry granules is always stick to a mass so it is required to screen again. The diameter of mesh can be same or slightly smaller than the previous one. After dry screening and blending with lubricants, calculate the tablet weight then press to obtain tablets. Tablet weight is obtained primarily by the content of drug. Using the following equation to calculate the tablet weight Desired average content of active ingredientTablet weight = Actual content of active ingredient in dry granulesChoice of punch’s diameter :
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