Abstract
There is a critical gap in the preclinical research of recombinant human interferons (rhIFNα-2b and rhIFN-γ), as most studies focus on modified variants, which complicates the understanding of the native molecules' properties. This study addresses this limitation by comprehensively evaluating the structural stability and intrinsic toxicity of purified IFNs. Our findings confirm that both interferons retain their bioactivity (antiviral, antiproliferative, and immunomodulatory) and exhibit remarkable stability under controlled conditions. Accelerated stability assays showed that neither protein lost biological potency after 18 days at various temperatures, supporting their potential as liquid formulations. Acute and sub-chronic toxicity studies in rodent, non-rodent, and higher-organism animal models showed no signs of toxicity, even at doses 100 to 300 times higher than therapeutic levels. These assays, combined with the absence of pyrogens, support a favorable safety profile for clinical use, with no evidence of systemic or structural damage. This work establishes a reproducible experimental model and lays the groundwork for future preclinical evaluations. We underscore the importance of characterizing the safety profile of active pharmaceutical ingredients from the earliest stages of biopharmaceutical development to ensure a safe and well-founded transition to human clinical trials. Furthermore, these results open the door for the development of advanced formulations and alternative routes of administration, such as the intranasal route, an area with significant potential.