| In this paper, gastrodin was selected as the model drug to prepare sustained-release tablets(ST), osmotic pump controlled-release tablets(OPT) and sustained-release pellets(SP). At last, the pharmacokinetic study of OPT and SP was performed.The in situ rat intestinal absorption property of gastrodin was investigated by means of single-pass intestinal perfusion technque in order to supply biopharmaceutical bases for drug formulation design. The results showed that perfusion flow rate could significantly affect the values of Ka and Papp; drug concentration ranged from 15 to 150 μg·ml-1 had no significantly effect on the values of Ka and Papp. Gastrodin can be ingested in the whole intestines and the absorption of it was good at the upper and middle intestinal segments while the absorption at the underpart was not so good as other parts.In the formulation study of ST, HPMC, CMC-Na were used to make the tablets. The effects of many factors including formulation and technique on the release behavior of tablets were investigated. Based on the results of single factor tests, an optimal self-prepared ST was screened.Under the condition of constant coating parameters, single factor tests were carried out on the formulation of tablet core and coating material, procedure as well as the in vitro release condition, which affect the release behavior of OPT. Results showed that the amount of NaCl, the amount and the kind of PEG, the weight of coating all influence the drug release behavior, while the diameter of orifice, the release medium and the method of dissolution had no...
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