Design and evaluation of subcutaneous implantable drug delivery system of tramadol using natural biodegradable polymer

This present research study was carried out to develop and evaluate the subcutaneous implants of chitosan for the administration of tramadol. Tramadol is one of the centrally acting analgesics with opioid agonist properties and can be safely used in such condition without the side effects. Rod shaped implants of 1 mm diameter and 2.7 mm in length were prepared by extrusion method, using a specially designed galaxy extruder. Implants were analyzed for drug content uniformity, thickness, weight variation, short term stability study. In vitro release study in phosphate buffer at 37 ± 1 o C, demonstrated that the rate of release of the tramadol from the implant matrix was a function of concentrations of the polymer. The implant formulations, having different concentrations of crosslinking, show varied drug release, can be extended for 17 days, compared to drug released from implants with no crosslinking. Thus, crosslinikng effectively control the amount of drug release. The release of drug from all implant formulations was uniform and was spread over a period of 17 days. The implant formulations were found sterile, uniform in weight, drug content and size. Short term stability studies of drug implants revealed that the implants formulations were stable, and there were no significant changes in the physical appearance and drug content of the implants formulations. Data obtained from the study suggest that the implants prepared from chitosan would be promising as an interesting biodegradable system for sustained delivery of tramadol for the pain management.