A local delivery system for fentanyl based on biodegradable poly(L-lactide-co-glycolide) oligomer

To obtain a sustained fentanyl delivery with effective and precise control, fentanyl loaded wafer was fabricated using poly(L-lactide-co-glycolide) (PLGA) oligomer by direct compression method. XRD and DSC analysis indicated the presence of crystalline drug in the wafers. The release of fentanyl from PLGA wafer was determined to be primarily diffusion controlled, but swelling and erosion also contributed to the release process. In vitro release studies showed that different release patterns and rates could be achieved by simply modifying factors in the preparation conditions. The wafer degradation profiles were also investigated to understand the drug release mechanism. Gravimetric studies of mass loss of wafers during the incubation revealed that the weight loss increased apparently after 4 days. These results indicate that the polymer degradation was contributed to drug release followed by diffusion. From the results, this constant localized release system can potentially provide anesthesia for a longer period than injection or topical administration.