Protein-Sugar-Glass Nanoparticle Platform for the Development of Sustained-Release Protein Depots by Overcoming Protein Delivery Challenges Poulomi Polley, † Shivam Gupta, †,§ Ruby Singh, † Arpan Pradhan, ‡ Suparna Mercy Basu, † Remya V., † Sunil Kumar Yadava, † and Jyotsnendu Giri* ,† † Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi 502285, Telangana, India ‡ Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra, India § Department of Bioengineering, School of Engineering, The University of Tokyo, Tokyo 113-8654, Japan * S Supporting Information ABSTRACT: Therapeutic protein depots have limited clinical success because of the presence of critical preparation barriers such as low encapsulation, uncontrolled release, and activity loss during processing and storage. In the present study, we used our novel protein-nanoencapsulation (into sugar-glass nanoparticle; SGnP) platform to prepare a protein depot to overcome the abovementioned formidable challenges. The SGnP-mediated microparticle protein depot has been validated using four model proteins (bovine serum albumin, horseradish peroxidase, fibroblastic growth factor, and epidermal growth factor) and model biodegradable poly(lactic-co-glycolic acid) polymer system. The results show that our protein-nanoencapsulation- mediated platform provides a new generic platform to prepare a protein depot through the conventional emulsion method of any polymer and single/multiple protein systems. This protein depot has the required pharmaceutical properties such as high encapsulation efficiency, burst-free sustained release, and protein preservation during processing and storage, making it suitable for off-the-shelf use in therapeutic protein delivery and tissue engineering applications. KEYWORDS: protein depot, protein nanoencapsulation, double emulsion, microparticles, protein delivery, protein therapeutics, tissue engineering 1. INTRODUCTION Advances in production strategies and technological progress in the field of biotechnology have created a surge in the availability of therapeutic protein molecules. 1,2 These mole- cules are attractive candidates over small molecules due to their high target specificity and efficacy with low off-target effects with normal biological processes. With proteins being labile in a physiological environment and having a short half- life, the current protein therapy standard of care requires frequent subcutaneous injections (few times a week or daily). 3,4 This leads protein therapy to have poor patient compliance and is expensive due to higher than desired doses. 1-4 Therefore, there is an unmet clinical need to develop sustained-release formulation or protein depot to improve patient compliance and efficacy and make the protein therapy cost-effective. 5 Microparticulate formulations of protein depot for long-term controlled release of active therapeutic protein have immense clinical importance for the treatment of many diseases, conditions, and regeneration of specific tissues. 6-11 Despite the high potential of biodegradable polymer-based depots, clinical success has been limited for few small molecules and peptide/protein formulation due to the presence of critical barriers such as low encapsulation efficiency, uncontrolled release, and activity loss during processing and storage. 12-14 The known example is Nutropin Depot, a sustained delivery system of recombinant human growth hormone (rhGH) encapsulated into biodegradable Received: September 30, 2019 Revised: November 20, 2019 Accepted: November 21, 2019 Published: December 3, 2019 Article pubs.acs.org/molecularpharmaceutics Cite This: Mol. Pharmaceutics 2020, 17, 284-300 © 2019 American Chemical Society 284 DOI: 10.1021/acs.molpharmaceut.9b01022 Mol. Pharmaceutics 2020, 17, 284-300 Downloaded via INDIAN INST OF TECH HYDERABAD on November 16, 2022 at 04:25:16 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.