@article{SchulzJakschSchubeletal.2014, author = {Schulz, Anita and Jaksch, Sebastian and Schubel, Rene and Wegener, Erik and Di, Zhenyu and Han, Yingchao and Meister, Annette and Kressler, J{\"o}rg and Kabanov, Alexander V. and Luxenhofer, Robert and Papadakis, Christine M. and Jordan, Rainer}, title = {Drug-Induced Morphology Switch in Drug Delivery Systems Based on Poly(2-oxazoline)s}, series = {ACS Nano}, volume = {8}, journal = {ACS Nano}, number = {3}, doi = {10.1021/nn406388t}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120766}, pages = {2686-96}, year = {2014}, abstract = {Defined aggregates of polymers such as polymeric micelles are of great importance in the development of pharmaceutical formulations. The amount of drug that can be formulated by a drug delivery system is an important issue, and most drug delivery systems suffer from their relatively low drug-loading capacity. However, as the loading capacities increase, i.e., promoted by good drug-polymer interactions, the drug may affect the morphology and stability of the micellar system. We investigated this effect in a prominent system with very high capacity for hydrophobic drugs and found extraordinary stability as well as a profound morphology change upon incorporation of paclitaxel into micelles of amphiphilic ABA poly(2-oxazoline) triblock copolymers. The hydrophilic blocks A comprised poly(2-methyl-2-oxazoline), while the middle blocks B were either just barely hydrophobic poly(2-n-butyl-2-oxazoline) or highly hydrophobic poly(2-n-nonyl-2-oxazoline). The aggregation behavior of both polymers and their formulations with varying paclitaxel contents were investigated by means of dynamic light scattering, atomic force microscopy, (cryogenic) transmission electron microscopy, and small-angle neutron scattering. While without drug, wormlike micelles were present, after incorporation of small amounts of drugs only spherical morphologies remained. Furthermore, the much more hydrophobic poly(2-n-nonyl-2-oxazoline)-containing triblock copolymer exhibited only half the capacity for paclitaxel than the poly(2-n-butyl-2-oxazoline)-containing copolymer along with a lower stability. In the latter, contents of paclitaxel of 8 wt \% or higher resulted in a raspberry-like micellar core.}, language = {en} }