Life cycle assessment of fine chemical production: a case study of pharmaceutical synthesis

Abstract

Pharmaceuticals have been recently discussed in the press and literature regarding their occurrence in rivers and lakes, mostly due to emissions after use. The production of active pharmaceutical ingredients (APIs) has been less analyzed for environmental impacts. In this work, a life cycle assessment (LCA) of the production of an API from cradle to factory gate was carried out. The main sources of environmental impacts were identified. The resulting environmental profile was compared to a second pharmaceutical production and to the production of basic chemicals. Detailed production data of a pharmaceutical production in Basel, Switzerland were used as the basis of this work. Information about the production of precursor chemicals was available as well. Using models and the ecoinvent database to cover remaining data gaps, a full life cycle inventory of the whole production was created. Using several life cycle impact assessment methods, including Cumulative Energy Demand (CED), Global Warming Potential (GWP), Eco-Indicator 99 (EI99), Ecological Scarcity 2006, and TRACI, these results were analyzed and the main sources of environmental burdens identified. Pharmaceutical production was found to have significantly more environmental impacts than basic chemical production in a kilogram-per-kilogram basis. Compared to average basic chemical production, the API analyzed had a CED 20 times higher, a GWP 25 times higher and an EI99 (H/A) 17 times higher. This was expected to a degree, as basic chemicals are much less complex molecules and require significantly fewer chemical transformations and purifications than pharmaceutical compounds. Between 65% and 85% of impacts were found to be caused by energy production and use. The fraction of energy-related impacts increased throughout the production process. Feedstock use was another major contributor, while process emissions not caused by energy production were only minor contributors to the environmental impacts. The results showed that production of APIs has much higher impacts than basic chemical production. This was to be expected given the increased complexity of pharmaceutical compounds as compared with basic chemicals, the smaller production volumes, and the fact that API production lines are often newer and less optimized than the production of more established basic chemicals. The large contributions of energy-related processes highlight the need for a detailed assessment of energy use in pharmaceutical production. The analysis of the energy-related contributions to the overall impacts on a process step level allows a comprehensive understanding of each process’ contribution to overall impacts and their energy intensities. Environmental impacts of API production were estimated in a cradle-to-gate boundary. The major contributors to the environmental impacts in aggregating methods were resource consumption and emissions from energy production. Process emissions from the pharmaceutical manufacturing plant itself were less of a concern in developed countries. Producers aiming to increase their sustainability should increase efforts to reduce mass intensity and to improve energy efficiency. Pharmaceutical companies have increased their efforts to optimize resource efficiency and energy use in order to improve their environmental performance. The results of this study can be used as a first step to perform a full cradle to grave LCA of pharmaceutical production and use, which could include other important phases of the pharmaceutical product life cycle. To assess a commercial pharmaceutical, the results of API production have to be compared to the contributions of other ingredients and formulation.