Real-Time Monitoring of Biopharmaceutical Crystallization: Chord Length Distribution to Crystal Size Distribution for Lysozyme, rHu Insulin, and Vitamin B12

Abstract

This investigation is focused on designing an effective strategy for the real-time monitoring of biopharmaceutical crystallization using focused beam reflectance measurement (FBRM). Lysozyme, rHu insulin, and vitamin B12 were selected as model biopharmaceutical molecules for the study. Under selected experimental conditions, lysozyme exhibits polymorphism with tetragonal and needle-shaped crystals, rHu insulin forms rhombohedral crystals, and vitamin B12 forms polyhedral-shaped crystals. Focused beam reflectance measurements were performed to obtain the real time chord length distribution (CLD) of crystals obtained using static and dynamic conditions. Mathematical models were developed for converting CLD data obtained using FBRM measurements into the useful crystal size distribution (CSD) data for low (tetragonal, rhombohedral and polyhedral) and high aspect ratio crystals (needle). For high-aspect-ratio crystals, both width-based and length-based models were developed for capturing the CSD. The model val...