[Concentration of biyankang extracts using multi-stage membranes separation].

Multi-stage membranes processes, including ultrafiltration and nanofiltration are used in concentration of Biyankang extracts at room temperature, and the concentrations of main active ingredient in retentions after membrane processes were determined by HPLC. The results showed that the removal rate of water is about 45%, and the cost is only one fourth of the vacuum heating method. The retention rates of buddleoside and ephedrine hydrochloride are above 80% and 90% respectively, which meet the efficient concentration and energy-saving needs. The concentration method of Biyankang with multi-stage membranes processes provides some instructive theories and experimental foundations.