Personalization of Intravaginal rings by droplet deposition modeling based 3D printing technology

Intravaginal rings (IVRs) are long-acting drug device systems designed for controlled drug release in the vagina. Commercially available IVRs employ a one-size-fits-all development approach, where all patients receive the same drug in similar doses and frequencies, allowing no space for dosage individualization for specific patients' needs. To allow flexibility for dosage individualization, this study explores the impact of infill-density on critical characteristics of personalized IVRs, manufactured using droplet deposition modeling three-dimensional (3D) printing technology. The model drug was dispersed on the surface of thermoplastic polyurethane pellets using an oil coating method. IVR infill-density ranged from 60 to 100 %. The compatibility of the drug and matrix was assessed using thermal and spectroscopic analyses. The IVRs were evaluated for weight, porosity, surface morphology, mechanical properties, and in vitro drug release. The results demonstrated high dimensional accuracy and uniformity of 3D-printed IVRs, indicating the robustness of the printing process. Increasing infill-density resulted in greater weight, storage modulus, Young's modulus, Shore hardness, and compression strength, while reducing the porosity of IVRs. All IVRs showed a controlled drug release pattern when tested under accelerated conditions of temperature for 25 days. Notably, greater infill-densities were associated with a decrease in the percentage of drug released. Overall, the study demonstrated that infill-density was an important parameter for personalizing the critical characteristics of the 3D-printed IVRs to fit individual patient needs.