Formulation and Evaluation of Sustained Release Pellets of Tramadol HCl Using 3 Full Factorial Design

The present research concerns the formulation and evaluation of sustained release pellets filled capsule of opioid analgesic, Tramadol HCl. Development of sustained release dosage form is to maintain therapeutic blood levels of the drug for extended period of time. Sustained release formulation provides uniform concentration at absorption site, maintains plasma concentration within a therapeutic range, reduces the dosage frequency and minimizes the side effects (nausea) associated with drug by avoiding dose dumping effect. Oral sustained release pellet formulations of Tramadol HCl were prepared using extrusion-spheronization technique. Pellets provide specific advantages of smoother plasma concentration profile and gradual absorption than tablet. HPMC K100M and EC along with the coating of Eudragit RSPO were chosen to achieve the desired dissolution profile. Their concentrations were optimized using 3 full factorial design to achieve the aim of sustaining the drug release for 12 hours. The prepared pellets were studied for different flow properties and drug release studies.