Exergetic sustainability assessment of batch versus continuous wet granulation based pharmaceutical tablet manufacturing: a cohesive analysis at three different levels

Abstract

Identifying better performing Active Pharmaceutical Ingredient (API) synthesis routes with reference to green chemistry and green engineering principles was of the highest importance in the pharmaceutical industry during the past decade. However, very little attention was paid to other life cycle stages such as the Drug Product (DP) production, packaging and distribution. In this case, the environmental sustainability of batch versus continuous granulation based tablet manufacturing is quantified from a resource point of view by conducting Exergy Analysis (EA) and Exergetic Life Cycle Analysis (ELCA) at three different levels in order to identify and locate resource losses throughout the pharmaceutical supply chain. Assessing the potential implementation of the continuous production line ConsiGma™ at the Janssen-Cilag SpA pharmaceutical manufacturing plant and thereby replacing the conventional batch manufacturing mode would result in a resource consumption reduction of 10.2% (65.6 to 58.9 kJ_ex per tablet), 15.2% (111 to 94.0 kJ_ex per tablet) and 2.2% (2.3 to 2.2 MJ_ex per tablet) at the process (α), plant (β) and overall industrial level (γ) respectively. Focusing on DP production processes by excluding transiting exergy in API, excipients and packaging materials resulted in a reduction of 34.0%, 25.9% and 14.7% at the respective system boundaries. The API dose seemed to be the parameter with highest sensitivity towards environmental burden. From an emission point of view, a Carbon Footprint (CF) reduction of 2.0% (0.22 to 0.21 kg CO₂-eq per tablet) was obtained at the γ level in shifting from batch to continuous manufacturing of Tramacet®. Focusing on DP production revealed a CF reduction of 16.2%.