Tiaprofenic acid (TA) is a potent non-steroidal anti- inflammatory drug having a short half-life of 3 to 6 hours.Administration ofTAconventional doses might prevail serious side effects, in addition to patient inconvenience. The study aim at preparing TAsolid dispersions in the matrices of Eudragit RS 100 and RL 100 by coevaporation technique. The prepared solid dispersions were characterized for their physicochemical properties, the in vitro drug release as well as the analgesic activity using tail-flick method. The results obtained showed that dispersion of the drug in RS polymericmatrix resulted in a retarding action on the drug release, while the dispersion in RL polymer type slightly retarded drug release in higher polymeric weight ratios, due to the greater number of quaternary ammoniumfunctions on RL surfaces. The IR and PXRD studies proved the homogeneous dispersion of TA in the polymer matrices. Moreover, The maximum analgesic activity of TA-Eud RS100 (1:3) coprecipitate was between 6.5 and 7 hours extended to 11 hours, while themaximumanalgesic activity of untreated drugwas between 1.5 and 2 h.