The Solvent Selection Guide was the first green chemistry tool to be developed by the ACS Green Chemistry Institute® Pharmaceutical Roundtable. This instrument is imperative because, while Process Mass Intensity Tool (PMI) is able to explain how efficient the use of mass is, it does not distinguish the hazard of the solvent being used. Solvents are used for reactions, extractions, distillations, washing, etc., which results in a solution.
During pharmaceutical process development, solvent selection is key in determining the sustainability of future commercial production methods. Solvents contribute over 50% of the total materials used to make a pharmaceutical product. The Solvent Selection Guide allows scientists to make informed decisions as they develop processes at the bench. It’s easier to start research and development with a green solvent than trying to later replace a more hazardous solvent with a less hazardous one.
The ACS GCI Pharmaceutical Roundtable Solvent Selection Guide is adapted from guides developed by Astra Zeneca, a multinational pharmaceutical and biologics company, and Glaxo SmithKline, a multinational pharmaceutical, biologics, vaccines and consumer healthcare company. AstraZeneca’s tool is a table of solvents with 10 different criteria attached to it: two for safety (flammability, resistivity), one for health, and seven for environment, including life cycle analysis. Each criterion is scored between 1 and 10, with a 3-color code (green, yellow, and red) to facilitate the analysis1. Glaxco SmithKline’s guide is similar, but has two safety criteria, one health, and three environmental. It also has red flags for high boiling solvents and solvents with regulations and has 110 solvents all together1.
The Pharmaceutical Roundtable’s guide is separated into three categories to identify what is considered a desirable solvent and what is not. The red category identifies undesirable solvents such as pentane, chloroform, and benzene. Yellow colored solvents are usable such as isooctane and heptane, and green are the preferred solvents such as water, methanol, and acetone.
The Roundtable is continuing to develop this guide due to new solvents and missing data points that will need to be filled.
1Cruciani, P., Ducandas, V., Flemming, H.W., Guntrum, E., Hosek, P., Isnard, P., Letestu, S., Pardigon, O., Prat, D., Ruisseau, S., Senac, T. Sanofi’s Solvent Selection Guide: A Step Toward More Sustainable Processes, ACS Publications, 2013.
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