Polyester-Based Nanoparticles for Delivery of Therapeutic Proteins.

Therapeutic proteins are widely used to treat severe conditions, such as oncologic and metabolic diseases, and also for vaccination. They are recognized for its high biopotency, but their hydrophilicity and high molecular weight make its transport through membranes difficult to achieve. They may also suffer in vivo structural instability caused by a proteolytic cleavage, turning them biological inactive. Polyester-based nanoparticles are useful tools to overcome such problems, and deliver therapeutic proteins in a controlled and localized manner, decreasing the number of administrations needed and enhancing the therapeutic outcome. The biodegradable and biocompatible nature of such carriers makes them feasible to be administered by invasive and noninvasive routes. Since nanoparticles are produced in suspension form, they are usually lyophilized to increase its long-term storage stability. Therefore, the aim of this work is to propose an intuitive protocol for production and lyophilization of polyester-based nanoparticles for therapeutic proteins delivery. The characterization techniques to evaluate the nanoparticle and lyophilisate features, as well as the structural stability of the loaded protein are also described. For these purposes, PLGA nanoparticles and human insulin are used as models.