3D printing of vaginal rings with personalized shapes for controlled release of progesterone.

Vaginal rings are gynecological drug delivery devices with fixed shapes, sizes and drug doses. Here 3D printed personalized progesterone-loaded vaginal rings were prepared. Progesterone was mixed with polyethylene glycol (PEG) 4000 to form a solid dispersion that was cut into pieces. The mixture of poly(lactic acid) (PLA)/polycaprolactone (PCL) (8:2) and Tween 80 were mixed with the above pieces and hot-melted to form filaments. A fused deposition modeling (FDM) printer was used to prepare "O", "Y" or "M"-shaped vaginal rings with the filaments. Differential scanning calorimetry and X-ray powder diffraction showed that amorphous progesterone existed in the rings. Moreover, progesterone did not decompose in the preparation according to the thermal gravimetric analysis. Surface pores and inner channels appeared in the rings due to PEG 4000 dissolution and Tween 80 made the rings wettable. The "O" ring had higher dissolution than the "Y" and "M" rings due to its higher surface area/volume ratio and special shape. The vaginal rings showed the long-term sustained release of progesterone for more than 7 days with diffusion-controlled release behavior. The 3D printed vaginal rings are promising local gynecological medications. 3D printing is an effective strategy for preparation of personalized and customized medications.