Formulation of Recombinant Therapeutic Proteins: Technological Innovation, Regulations, and Evolution Towards Buffer-Free Formulations.

Abstract

Background/Objectives: Formulating recombinant therapeutic proteins is essential to ensure their safety, efficacy, and stability. A growing trend in biopharmaceutical development is the move toward buffer-free formulations, which aim to reduce immunogenicity, improve tolerability, and simplify production. This review explores technological advances, regulatory perspectives, and safety considerations related to this shift. Methods: A systematic documentary review was conducted using the PSALSAR framework. Scientific publications, patents, and regulatory documents (2020-2025) were retrieved from PubMed, Scopus, Web of Science, and regulatory databases (FDA, EMA). Inclusion criteria focused on recombinant proteins, buffer-free formulations, and regulatory alignment. Results: The findings reveal an increasing adoption of self-buffering strategies in high-concentration subcutaneous biologics. Technologies such as Fc-fusion, PASylation, and XTENylation enhance stability without conventional buffers. Regulatory bodies are progressively accepting minimalist formulations, provided safety and biosimilarity are demonstrated. However, intellectual property barriers limit formulation transparency. A synthesis of recent FDA and EMA approvals illustrates this formulation evolution. Conclusions: Buffer-free formulations offer a promising alternative for therapeutic protein development by improving patient experience and reducing formulation complexity. They align with biosimilar goals and regulatory trends, although long-term transparency and safety assessments remain critical for widespread adoption.