(M1330-06-31) Residual Moisture Influences Virus Stability in a Film Based Dosage Form for Long-Term Stability of Biologics

Purpose: Moisture content greatly influences the physical properties, quality, and shelf life of all drug products. This can especially be seen in lyophilized biologics, where a general target of 1-3% residual moisture is desired for optimal stability [1]. The objective of this study is to evaluate the role relative humidity (RH) during manufacturing – and the resulting residual moisture – plays in the thermostability of live viruses stored within the film.

Methods: Films containing recombinant adenovirus encoded with β-galactosidase were produced using an optimized formulation, cast in unit dose polystyrene molds, and dried in a tightly controlled environment set to 18°C at varying RH. Drying was complete when films reached equilibrium with the setpoint RH at minimum 14-16 hours. Residual moisture was assessed by Karl Fischer volumetric titration. Films were packaged and stored under stressed (40°C, RH 90%) conditions [2]. At each timepoint, films were rehydrated, and infectious virus was assessed by an in vitro infectious titer assay [2].

Results: Films dried at 53% and 45% RH created films with an initial residual moisture of 17% and 13.9%, respectively. Furthermore, after 1 day storage at 40°C, 90% RH, films dried at 53% RH preserved 91.4% of the original number of infectious virus particles, while films dried at 45% could only sustain 83.7% (p < 0.05).

Conclusion: Relative humidity during processing plays a significant role in the residual moisture content of films. It has been suggested that an optimal moisture range exists for lyophilized biologics, however an optimal range has not been determined for biologics within a film-based formulation [1,2]. These initial studies confirm that initial residual moisture due to setpoint RH during processing impacts the thermostability of adenovirus stored within the film matrix. The goal of future studies is to determine the optimal residual moisture to impart the greatest long-term stability for biologics stabilized within the film matrix. Lastly, other vectors like adeno-associated virus (AAV) will be evaluated to investigate the extent to which residual moisture impacts thermostability of other biologics.

References: 1. Towns, J. K. (1995). Moisture content in proteins: its effects and measurement. In Journal of Chromatography A (Vol. 705).
2. Bajrovic, I., Schafer, S. C., Romanovicz, D. K., & Croyle, M. A. (2020). Novel technology for storage and distribution of live vaccines and other biological medicines at ambient temperature. Science Advances, 6(10), 1–14. https://doi.org/10.1126/sciadv.aau4819

Acknowledgements: This project was supported by the UT Austin Provost Supplemental Recruitment Fellowship, the UT Austin College of Pharmacy Endowed Fellowship: Max and Mary Anne Burlage Fellowship, the AFPE Pre-Doctoral Fellowship: Herb and Nina Demuth Memorial Award in Pharmaceutics, and by Jurata Thin Film.