Generalized Digital Framework for the Sustainable Recovery of Active Pharmaceutical Ingredients from Solid Drug Formulations

The global rise in pharmaceutical use over the past two decades has led to more unused drug products and a corresponding surge in pharmaceutical waste. Thus, there is an impetus to develop processes for recovering active pharmaceutical ingredients (APIs) from unused drugs. This study introduces a multiobjective optimization framework for solvent screening to enable sustainable recovery of APIs using a general separation train with cooling crystallization as the final step. The objectives considered are recovery during crystallization, the relative solubilities of API and excipients, and process mass intensity (PMI), which accounts for process sustainability. The framework is demonstrated using various commercial formulations of paracetamol (PA) for experimental validation. The recoveries obtained were in the range 57–63%, and the recovered API samples were of high chemical purity based on characterization using Raman spectroscopy and powder X-ray diffraction (PXRD).