OBJECTIVE:To optimize the formulation technology of Ibuprofen sustained-release dropping pill and evaluate its in vitro drug-release characteristics. METHODS:Using stearic acid as sustained-release matrix,polyethylene glycol 6000 as imme-diate-release matrix,melting method was used to prepare the Ibuprofen sustained-release dropping pill. Using the comprehensive scores of roundness,weight difference,drug loading rate,in vitro drug-release time as indexes,drug-matrix mass ratio,liquid tem-perature,condensation temperature,dropping distance as factors,orthogonal test was adopted to optimize the formulation technolo-gy,and verification test was conducted. In media of deionized water,hydrochloric acid solution (pH 1.2),phosphate buffer (pH 4.5,6.8),the in vitro drug-release were compared between self-made sustained-release dropping pill and commercially available Ibuprofen sustained-release capsule,which were fitted for former drug-release behavior. RESULTS:The optimal formulation tech-nology was as follows as mass ratio of ibuprofen-polyethylene glycol 6000-stearic acid of 4.0:15.3:0.7,liquid temperature of 83 ℃,condensation temperature of 8 ℃,and dropping distance of 11 cm. The weight difference of prepared 3 batches of Ibupro-fen sustained-release dropping pill was 2.067%(RSD=1.19%),roundness was 96.73%(RSD=0.28%),drug loading rate was 96.31%(RSD=0.19%),cumulative release rate in 12 h was 93.05%(RSD=0.81%). The f2 values of self-made sustained-re-lease dropping pill and commercially available Ibuprofen sustained-release capsule were greater than 50,the former one fitted more into Higucci equation(r=0.9881-0.9972). CONCLUSIONS:The formulation technology of Ibuprofen sustained-release dropping pill is successfully optimized,and in vitro drug-release behavior of prepared sustained-release dropping pill is similar to commercial-ly available Ibuprofen sustained-release capsule.