The pharmaceutical industry has witnessed exponential growth in production volumes, driven by factors such as an aging global population and the COVID-19 pandemic. To meet the demand for high product quality alongside increased productivity, there is a growing emphasis on developing innovative Fermentation Analytical Technology (FAT) and Process Analytical Technology (PAT) tools for real-time performance monitoring, modeling, measurement, and control. Building on our earlier work involving in-line monitoring of Bordetella pertussis fermentations using fluorescence spectroscopy, this review explores and compares the applications of vibrational and fluorescence spectroscopy for real-time bioprocess monitoring. We examine recent technological advancements and ongoing challenges in the field. Various spectroscopic techniques are evaluated in terms of cost-effectiveness and practical applicability, with a particular focus on in-line spectroscopy as a promising, low-cost solution for effective bioprocess monitoring.

Messenger RNA-lipid nanoparticle (mRNA-LNP)-based drug products represent a promising platform for prophylactic and therapeutic applications. However, their limited stability poses significant challenges for storage and global distribution. The instability of mRNA-LNP products makes them dependent on ultra-cold chain systems. This instability is driven by various physicochemical factors, including temperature, pH, light exposure, oxidation, aggregation, shear stress, and humidity. These factors destabilize the physical and chemical integrity of both mRNA and lipid nanoparticle (LNP) components, leading to reduced vaccine potency and potentially increasing the risk of adverse safety outcomes. Understanding these factors and their mechanisms is crucial for retaining mRNA-LNP efficacy. This review discusses the key physicochemical instability factors and molecular degradation mechanisms responsible for the structural and functional deterioration of mRNA-LNP formulations. Further, we summarize the stabilization strategies and analytical methods used to detect and quantify the degradation of mRNA-LNP products. Addressing these challenges is critical for advancing next-generation nucleic acid-based drug products and LNP-based delivery systems.