Poor solubility of therapeutically valuable drugs as well as new potential drug candidates represents an increasing challenge for the pharmaceutical industry. One way to tackle this problem is to make use of sophisticated drug delivery systems (DDS) that achieve efficient transportation of the (potentially toxic) compound to its biological target. Besides widely established vehicles like liposomes, amphiphilic polymer micelles consisting of ABA-triblock copolymers of poly(2-oxazoline)s (pOx) and / or poly(2-oxazine)s (pOzi) resemble an interesting alternative and have been shown to provide maximum loading capacities (LC) of up to and more than 50 wt% for a variety of therapeutically valuable drugs, e.g. paclitaxel. Such formulations are usually prepared via hydration of a thin film containing the polymers and drugs, after removal of the ethanol solution. As for any other polymer micelle based formulation, the more hydrophobic B blocks are believed to function as the main drug reservoir, i.e. the part of the micelle where the drugs are encapsulated, whereas the more hydrophilic A blocks serve as a "protective", solubilizing corona of the micelle (Figure ). Composed largely of hydrophobic elements but also more polar tertiary amides, these polymeric entities contain readily-modifiable sidechains and thus represent a versatile chemical toolbox that has garnered much attention in biomedical sciences in recent years. are listed on the right. antioxidant and anti-tumor effects, was chosen as the model compound and has been extensively characterized experimentally as a cargo in previous work. The investigated systems are A-pPrOzi-A (additionally labeled [10/2] or [10/6], depending on the polymer/drug mass [w/w] ratio), A*-pPrOzi-A* exchanging pMeOx-based A blocks with pEtOx while keeping a similar mass ratio between hydrophilic and hydrophobic repeat units (with the hydrophobic units making up around 30 % of the polymer mass), as well as A-pBuOx-A containing the structural isomer pBuOx as B block. Thus, these systems represent exemplary cases in which an exchange of the A or the B blocks leads to a significant decrease in the maximum loading capacity.