A controlled porosity osmotic pump (CPOP) delivery system for sodium ferulate was prepared with cellulose acetate (CA) as semipermeable membrane, polyethyleneglycol 400 (PEG 400) as channeling agent and dibutylphthalate (DBP) as plasticizer and release controller. Effects of coating levels, PEG and DBP content and amount of sodium chloride on in vitro release were studied. Coating formulations were optimized by a L9 (34) orthogonal array design (OAD) with three factors at three levels using statistical analysis. Controlled porosity osmotic pump tablets of sodium ferulate made with the optimal formulation were found to have good in vitro and in vivo release characteristics.