Core cross-linked star shaped polymers possess unique physical properties that can be utilized as drug transporters for biomedical applications. However, detailed analysis of these polymer structures is not straightforward. Herein, we employ multi-detector gel permeation chromatography (GPC) to elucidate structural features of cross-linked stars prepared from the polymerisation of NIPAM via Cu(0)-mediated Reversible Deactivation Radical Polymerisation. Furthermore, we aim to show how varying the arm length and the core size of the star polymers can not only affect their structural properties but also their capacity to encapsulate drug-like molecules.