Selective Laser Sintering 3-Dimensional Printing as a Single Step Process to Prepare Amorphous Solid Dispersion Dosage Forms for Improved Solubility and Dissolution Rate

This study reports the development of ritonavir-copovidone amorphous solid dispersions (ASDs) and dosage forms thereof using selective laser sintering (SLS) 3-dimensional (3-D) printing in a single step, circumventing the post-processing steps required in common techniques employed to make ASDs. For this study, different drug loads of ritonavir with copovidone were processed at varying processing conditions to understand the impact, range, and correlation of these parameters for successful ASD formation. Further, ASDs characterized using conventional and advanced solid-state techniques including wide-angle X-ray scattering (WAXS), solid-state nuclear magnetic resonance (ssNMR), revealed the full conversion of the crystalline drug to its amorphous form as a function of laser-assisted selective fusion in a layer-by-layer manner. It was observed that an optimum combination of the powder flow properties, surface temperature, chamber temperature, laser speed, and hatch spacing was crucial for successful ASD formation, any deviations resulted in print failures or only partial amorphous conversion. Moreover, a 21-fold increase in solubility was demonstrated by the SLS 3-D printed tablets. The results confirmed that SLS 3-D printing can be used as a single-step platform for creating ASD-based pharmaceutical dosage forms with a solubility advantage.