Study On Oral Timed Release Gel Beads Of Leigongteng Extract

In this paper, a Traditional Chinese Medicine(TCM), Leigongteng (Tripterygium wilfordii Hook, f.), which have been used for centuries in China to treat rheumatoid arthritis (RA), was first selected as a hydrophobic model drug to prepare oral timed release pellets with 4 hour's lag time(T_lag). And calcium alginate gel beads was selected as drug loading matrices because of its highly pH-dependent characteristics of swelling and drug release.In order to meet with the necessity of multicriteria quality control for multicomponent in extract of Leigongteng, Ultraviolet spectrophotometry(UV) method and Colorimetric method was developed to determine the content of total alkoloids(TA) and total diterpene-lactones(TDL) respectively. High-performance liquid chromatography (HPLC) with UV detection was applied to quantify triptolide, a power active ingredient in the extract. TA was selected as index component for in vitro assay of drug release of pellets. Analytical methods above were precise, simple and reliable.The crude ethyl acetate extract of Leigongteng has been further purified by silica gel color spectrum, and TA, TDL, the main active component was enriched. Thus the measurable components of purified extract reached 50%, in which the content of TA>42% and TDL>8%, triptolide was controlled to<0.8% because its high side effect. Quality specification has been made. The solid powder of purified extract was stable in influential factor test of high temperature, high moisture and light.Equilibrium solubility (37℃) of TA, TDL and the total solid material in different media were determined respectively, which suggests that the extract...