Development and Evaluation of Implant using Hot-Melt Extrusion

In this study, poly(lactic-co-glycolic acid) (PLGA)-based subcutaneous implant containing metformin HCl was prepared by hot-melt extrusion (HME). This study aimed to evaluate swelling and dissolution behavior for application as subcutaneous implant. Implants containing metformin HCl were fabricated successfully at 30 rpm, 90oC by HME. Drugexcipient compatibility studies through FT-IR and DSC revealed the absence of any interaction between the drug and polymers. Dissolution rate and swelling ratio of metformin HCl was significantly affected by the type of PLGA. Dissolution rate increased as the ratio of -COOH terminal group and GA. By the results, we could confirm that the mechanism of drug release from implants is Korsmeyer-Peppas model (n=0.14~0.71) by combination of non-fickian diffusion and erosion. The formulation F7 with 65% of RG 752H and 5% of RG 502 was showed excellent swelling ratio with drug release control. In this study, mixing 5~10% of RG 502 with RG 752H can be expected to develop optimal implants exhibiting diffusion-controlled release for 3 months without initial burst release.