Freeze-drying-induced mutarotation of lactose detected by Timegated® Raman spectroscopy
An article titled Freeze-drying-induced mutarotation of lactose detected by Raman spectroscopy is published online in ScienceDirect and will be published in the European Journal of Pharmaceutics and Biopharmaceutics, Volume 205, in December 2024.
Freeze-drying is used in pharmaceutics and biologics to enhance the storage stability of sensitive biomolecules by keeping them dry at room temperature. The process requires excipients to preserve their properties upon reconstitution, but the molecular-level understanding of these excipients is limited. Non-invasive tools like infrared IR and Raman spectroscopy help predict excipient properties and changes during freeze-drying. The goal of optimizing freeze-drying is to reduce time and costs while ensuring a high-quality product for future use, which requires suitable tools and formulations.
This study emphasizes the potential of combining in silico MD simulations with Raman spectroscopy to uncover essential features of excipients used in biomaterial design that contribute to successful freeze-drying. By integrating these methods with traditional characterization methods, time and sample size could be minimized. Excipients for freeze-drying NFC hydrogel were screened using MD simulations, and their behavior in various states was evaluated with a PicoRaman M3 spectrometer utilizing Timegated® Raman technology, ensuring successful freeze-drying.
Researchers found that Raman spectroscopy and MD simulations can monitor quality and detect molecular changes in freeze-drying NFC hydrogel. Additionally, the study indicates that Raman spectroscopy is a sensitive tool capable of detecting alterations in molecular orientation within fresh, freeze-dried, and reconstituted formulations, which could be related to molecular-level interactions revealed from the MD simulations.
Read more about freeze-drying/lyophilization with Timegated® Raman Technology.
Abstract
Freeze-drying enables delicate, heat-sensitive biomaterials to be stored in a dry form even at room temperature. However, exposure to physicochemical stress induced by freeze-drying presents challenges for maintaining material characteristics and functionality upon reconstitution, for which reason excipients are required. Although wide variety of different excipients are available for pharmaceutical applications, their protective role in the freeze-drying is not yet fully understood. In this study, our aim was to use molecular dynamics simulations to screen the properties of different sugars and amino acids, which could be combined with plant-based nanofibrillated cellulose (NFC) hydrogel to provide protective matrix system for future freeze-drying for pharmaceuticals and biologics. The changes in the NFC-based formulations before and after freeze-drying and reconstitution were evaluated using non-invasive Timegate PicoRaman spectroscopy and traditional characterization methods. We continued to the freeze-drying with the NFC hydrogel formulations including lactose with and without glycine, which showed the highest attraction preferences on NFC surface in silico. This formulation enabled successful freeze-drying and subsequent reconstitution with preserved physicochemical and rheological properties. Raman spectroscopy gave us insights of the molecular-level changes during freeze-drying, especially the mutarotation of lactose. This research showed the potential of integrating in silico screening and non-invasive spectroscopical method to design novel biomaterial-based formulations for freeze-drying. The research provided insights of the molecular-level interactions and orientational changes of the excipients, which might be crucial in future freeze-drying applications of pharmaceuticals and biologics.
The authors of this research are Julia Monola, Elle Koivunotko, Jacopo Zini, Akseli Niemelä, Artturi Koivuniemi, Aleksi Kröger, Ossi Korhonen, Sami Valkonen, Arto Merivaara, Riina Harjumäki, Marjo Yliperttula, and Jere Kekkonen.
