Study On Oral Timed Release Pellets Of Doxofylline Hydrochloride

That pulsed release pellet drug delivery system draws peoples attention by its special release more and more. Timed release system as a part of pulsed release pellet drug delivery system was widely used. In this paper, Doxofylline was selected as a water-soluble model drug. According to the fact that asthma usually happens in midnight, the Doxofylline timed pellet is devised to the administered at evening and reaches its plasma concentration in midnight. The researches made were as follows:(1) Ultraviolet spectrophotometry(UV) method was developed for in vitro assay of drug content and release of pellets and determination of physicochemical properties. High-performance liquid chromatography(HPLC) diction was applied to quantify the drug plasma concentration of dogs. Analytical methods were precise, simple and reliable, which offered safe methods for Rx project and the researches in vivo of Doxofylline.(2) As timed release pellets, its intestinal absorption was one point of the researches. To clarify the absorption of Doxofylline from gastrointestine, the absorption was studied by utilizing the rat intestinal absorption recirculation method in situ. No significant difference of value of Ka was absorbed among jejunum, ileum and colon. The results suggested that the intestinal of Doxofylline was suitable for first-order kinetics via passive transport mechanism.(3) The researches of preparation design: The timed release pellets consist of three laminar layer from center to outside: the core, the swelling agent layer and the controlled layer. The theory of timed-controlled release pellets was controlled penetration of liquid to control lag time. The swollen power exceeds the resistance...