Waste generation, product yield evaluation and exergy analysis during bisphosphonate synthesis and medical drug production processes

During the chemical synthesis of zoledronic acid under GMP (good manufacturing practice) conditions, the most energy consuming step was found to be crystallization. On the other hand, the most energy consuming step during sterile finished product manufacturing was filling, followed by sterilization of the primary packaging equipment and the materials, and the operation of the HVAC system. The initial cumulative degree of perfection (CDP) was calculated to be 1.47 × 10−2% for the API synthesis, however exergy efficiency of the synthesis process to 2.29 × 10−2% with increasing the yield through process optimization. The CDP of the finished product was 17% and 75% before and after packaging of the finished product, respectively. Synthesis at the maximum attainable conversion ratio and the highest exergy efficiency assures minimum waste generation.