Expanding GSK's Solvent Selection Guide--application of life cycle assessment to enhance solvent selections

Solvents play an important role in the pharmaceutical, chemical and allied industries, with millions of tons used and disposed of each year. GlaxoSmithKline (GSK) previously reported on the development of a Solvent Selection Guide (SSG) that provides scientists with concise environment, health and safety (EHS) data and guidance for solvents. The Guide facilitates the inclusion of EHS considerations in early process development decisions. Previous life cycle inventories and assessments of pharmaceutical synthesis have shown that solvent use consumes about 60% of the overall energy used to produce an active pharmaceutical ingredient (API) and accounts for 50% of the total post-treatment greenhouse gas emissions. In light of these findings, GSK's SSG has been enhanced to include life cycle inventory and assessment data for the most commonly used solvents in the company. The life cycle assessment module ranks solvents according to their potential life cycle impacts and provides detailed life cycle inventory and assessment information for each of the solvents included. The methodology used to develop the life cycle module for GSK's SSG is presented along with several examples of the detailed information provided. The importance of solvent optimization, recovery and recycling in reducing life cycle environmental impacts is highlighted and important considerations for solvent selection are also included. The research presented here represents one part of GlaxoSmithKline's (GSK) overall efforts to incorporate and maintain sustainable business practices for materials selection. List of symbols DAi average value of metric i for recovering an alcohol via distillation DNAi average value of metric i for recovering a non-alcohol via distillationi metric category (e.g. net mass, gross energy,GHG, etc.) j solvent (e.g. acetone, ethanol, etc.) mi lower limit of metric iMi upper limit of metric ir recovery percentage expressed as a fraction Sij value of metric i for solvent jSj life cycle score for solvent j = LCA ranking for solvent j = geometric mean of the scores for the eight metricsxi average value for metric ixij value of metric i for manufacturing of virgin solvent jxrij value of metric i for solvent j at a recovery percentage rri standard deviation for metric iPi multiplicatory over all metrics (i).[PUBLICATION ABSTRACT]