| Based on the chronopharmacology, pulsatile drug delivery system has the abilityof a controlled release system to deliver drugs at various rates over extended period,whereas the drug delivery system has never been employed in the field of Chinesemateria medica preparation. In this paper, Rutin which is a kind of flavovoids wasused as the model drug, and alginate/chitosan microcapsule was used as a novelmethod to prepare the pulsatile drug delivery system. As a result, the in vitrodissolution of the product showed excellent pulsed release characteristic.By means of alginate/chitosan complex coacervation, the perfect encapsulationefficiency of 71.02% was achieved in optimum conditions. Contrasting withemulsification method and precipitation method, alginate/chitosan was established tobe a promising method to encapsule Chinese materia medica.The study proved that the release characteristic depend on pH in vitro, as pH=1.2,it is zero order kinetic;as pH=6.8, it is pulsed. The released percentage is 7 timesmore than that in pH=1.2. The microcapsule responded to the change of pH, and therelease profile showed "S".Three researches was carried out to solve the problems that alginate/chitosanmicrocapsule confronted as pulsatile drug delivery system. First, for the purpose ofprolonging the lag-time that is gastric empty time in the original preparation, add gasforming agent to turn the microcapsule into gastric floating system. Meanwhile, thelag-time became 5h. Secondly, PVA was blended, and the encapsulation efficiencyincreased from 71.02% to 87.17%. Thirdly, for the purpose of improving the stability,Gel was blended, and the break percentage fall to 0% under experimental conditions.
|
PDF Full Text Request