Objective: To prepare
tetramethylpyrazine phosphate sustained release tablets and to investigate its quality in vitro
. Methods: Orthogonal design was utilized to obtain the best formula. The hydrophilic matrix material hydroxypropylmethyl cellulose(HPMC K 100M )was used to prepare
tetramethylpyrazine phosphate sustained release tablets by the wet granule compression technique. Ethylcellulose(EC,100cps)was used to adjust the releasing rate. The content of the major drug was determined by UV spectrophotometry at 295 nm. The drug release in vitro was determined according to the method of Chinese Pharmacopoeia(2000)and a survey of its stability was conducted. Results: The dissolution curves in vitro showed that the drug release could be best described by the Higuchi equation ( Q=30.2915 t 1/2 -6.7776,r =0.9937)and other indices matched the requirement of quality control on sustained release tablets in Chinese Pharmacopoeia(2000). Conclusions: The method of content determination was simple and sustained releasing rate was significant. It is worth doing further research in order to provide tetramethylpyrazine phosphate sustained release tablets for clinical use.