the present invention features a long - term controlled release formulation of the nalbuphine pro - soft drug , sebacoyl dinalbuphine ester , in combination with commonly used pharmaceutical excipient biodegradable polymer plga . said formulation was selected from the following groups of pharmaceutical formulations including such as : tablets , capsules , soft capsules , granules , suspensions , microspheres , oral implants , implantable injections and others . said long - term controlled release formulation significantly improved the dosage and frequency for administering nalbuphine to once per half month or few months , compared to four to six times per day in the traditional way , which is one of the major features and effects of the present invention . the major improvement of this invention can be achieved by confirmation of the pharmacokinetic profiles and the duration time of efficacy level of drug through in vivo experiments , subsequently improves the dosage and frequency of the traditionally used nalbuphine injections .