Lung cancer is the leading cause of cancer death because of smoking and air pollution. Therefore, new ideas should be provided for lung cancer treatment in which the delivery of anticancer drugs to the local tumor site can be achieved. For this purpose, we propose the use of stereocomplexed spherical microspheres with sizes between 0.5 and 10 μm loaded with doxorubicin (DOX) to be administered through the nasal route. In order to gain control over the microsphere morphology, size, and drug loading capacity, we systematically studied the influence of the solvent used for preparation and the functionalization of their building blocks, namely poly-l-lactide (PLLA) and poly-d-lactide (PDLA) with blocked or unblocked l-proline moieties. We could demonstrate that DOX release is generally determined by the size of the microspheres. The antiproliferative activity of DOX released from the different microspheres was shown in vitro using the A549 lung cancer cell line as a model. Moreover, when in direct contact to the cancer cells, smaller microspheres were uptaken and could serve as a reservoir for local drug release. Our findings not only provide a novel strategy to prepare PLA microspheres with controllable morphology and release of anti-cancer drugs but also offer additional possibilities for the application of stereocomplexed particles in anticancer therapy, with suitable sizes for nasal administration.

Novel polymer networks composed of biocompatible, hydrophilic poly(2-isopropenyl-2-oxazoline) (PiPOx), poly(ethylene oxide) (PEO), and selected biologically active compounds (cinnamic acid, benzoic acid or eugenol) were developed for potential antimicrobial applications. The applied crosslinking method, based on the addition reaction between oxazoline pendant groups and chosen reagents containing carboxyl functions, is relatively facile, free from by-products, and thus well suited for biomaterial preparation. The one-step synthesis enabled efficient network formation with high gel contents (>90%). The chemical structure of the newly synthesized networks was characterized using Fourier Transform Infrared-attenuated Total Reflection spectroscopy (FTIR-ATR) and ¹³C Magic-Angle Spinning (MAS) NMR. To evaluate the suitability for biomedical applications, swelling in water and the mechanical properties of the networks were investigated. The antimicrobial efficacy of the prepared hydrogels was tested in neutral medium both by the agar diffusion method and in the liquid culture against Gram-positive and Gram-negative strains: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Enterobacter cloaceae. All the tested hydrogels showed an antimicrobial effect in the direct contact zone. Moreover, the eugenol loaded hydrogel expressed a broader bacteriostatic effect inhibiting microorganism growth beyond the contact zone. These form-stable hydrogels with antibacterial properties may be of interest for designing materials dedicated to biomedical applications.