Development and Evaluation of Gelatin Microspheres of Tramadol Hydrochloride

To develop formulations for effective management of chronic pain without side effects associated with NSAIDs and COX-2 antagonists, Tramadol hydrochloride, an opioid antagonist, was encapsulated within Gelatin microspheres for controlled delivery for longer periods. The microspheres were prepared using a single emulsion technique and were investigated. Tramadol hydrochloride could be encapsulated into Gelatin microspheres with an entrapment efficiency of 97.2%. Spherical, transparent, and free-flowing microspheres were obtained. Scanning electron microscopy revealed the spherical structures under the magnification of 200 mu m. The FTIR and DSC analysis indicated the stability and compatibility of the drug in gelatin microspheres. The microspheres were in the suitable particle size range of 20 to 160 mu m. The drug was released continuously for a period of 12 hrs with a maximum release of 99.79%.