The porous osmotic pump based drug delivery system for excellent controlled release of drug for 24 hrs. The porous osmotic pump contains pore forming water soluble additives in the coating membrane, which after coming in contact with water, dissolve, resulting in an in situ formation of a microporous structure. The porous osmotic pump delivery from this system is not influenced by the different physiological factors. The present review is concerned with the patent study of drug release through controlled porous osmotic pump. This patent review is useful in knowledge of controlled porous osmotic pump for its application.