Objective: To optimize prescription technology of rhynchophylline sodium alginate gel microspheres

and investigate its in vitro release. Method: Rhynchophylline sodium alginate gel microspheres were prepared by dropping method

effects of the mass fraction of sodium alginate

CaCl2 concentration

ratio of sodium alginate and rhynchophylline

crosslinking time on drug release were investigated by single factor test

then its in vitro release curve was fitted. Result: Optimal formulation was as following:sodium alginate concentration 1.5%

ratio of sodium alginate sodium to rhynchophylline 1:1

CaCl2 concentration 0.18 mol·L-1;These prepared gel microspheres had a good appearance

encapsulation efficiency 92.45%

drug loading 3.71%;Drug released 33.14% in pH 6.8 phosphate buffer solution during 2 hours

released 62.11% during 6 hours

released 94.70% during12 hours

in vitro drug release behavior of Zero order release model was F=6.114 7t+23.47. Conclusion: These prepared gel microspheres had a good release behavior in pH 6.8 phosphate buffer solution

this optimized preparation technology was simple

feasible and repeatable.