https://www.selleckchem.com/products/trastuzumab-emtansine-t-dm1-.html Although a range of polymer-protein polyion complex (PIC) micelle systems have been developed in the literature, relatively little attention has been paid to the influence of polymer structure on the assembly, or to the mechanism of disassembly. In this work, Förster resonance energy transfer is used in combination with light sheet fluorescence microscopy and isothermal calorimetry to monitor the formation and stability of PIC micelles with various carboxylic-acid-based binding blocks in MCF-7 cancer spheroid models. All micelles are stable in the presence of free protein, but are unstable in solutions with an ionic strength >200 mm and prone to disassembly at reduced pH. Introducing carbon spacers between the backbone and the binding carboxylic acid results in improved PIC micelle stability at physiological pH, but also increases the pKa of the binding moiety, resulting in improved protein release upon cell uptake. These results give important insights into how to tune PIC micelle stability for controlled protein release in biological environments.The recent benefit-risk framework (BRF) developed by the Food and Drug Administration (FDA) is intended to improve the clarity and consistency in communicating the reasoning behind the FDA's decisions, acting as an important advancement in US drug regulation. In the PDUFA VI implementation plan, the FDA states that it will continue to explore more structured or quantitative decision analysis approaches; however, it restricts their use within the current BRF that is purely qualitative. By contrast, European regulators and researchers have been long exploring the use of quantitative decision analysis approaches for evaluating drug benefit-risk balance. In this paper, we show how quantitative modelling, backed by decision theory, could complement and extend the FDA's BRF to better support the appraisal of evidence and improve decision outcomes. After prov