We propose a framework for the preliminary screening of chemical process designs according to sustainability criteria. Through the implementation of each flowsheet in a process simulator, several indicators based on sustainability pillars, i.e. economy, society, and environment, are calculated and then analyzed employing data envelopment analysis (DEA) in order to select the most efficient designs considering multiple criteria simultaneously. Suboptimal alternatives are further investigated by adopting a retrofit analysis, aiming to identify the parameters that most contribute to the final indicators scores, and therefore highlighting the major sources of deviation from optimal conditions. We applied this framework on a case study based on various patents regarding the production of pioglitazone hydrochloride in order to validate the capabilities of our methodology. Our approach, which embeds process simulation, sustainability indicators, and DEA within the same procedure, will support practitioners during the sustainability assessment of promising process designs, removing the inefficient ones.