Microparticles are one of the key novel drug delivery systems has been widely used to precisely modulate release rate. Microparticles based polymeric systems fabricated using suitable carrier has been extensively explored as an effective matrix for controlled and sustained release delivery of many drugs. With the controlled release systems, the rate of drug release matches the rate of drug elimination, and therefore the drug concentration is within the therapeutic window for the majority of the 24-hr period.The aim of this study was to prepare Eudragit microspheres containing Tramadol HCl by...