The evaluation of the in vitro stability of stimuli-sensitive fatty acid-based microparticles for the treatment of lung cancer

The fatty acid-based microparticles containing iron oxide nanoparticles and paclitaxel are a viable proposition for the treatment of lung cancer. The microparticles inhaled as the dry powder can be guided to selected locations using an external magnetic field and when accumulated there the active compound release can be triggered by local hyperthermia. However, this general strategy requires that the active compound is released from microparticles and can reach the targeted cells before microparticles are removed. Isothermal titration calorimetry was used to demonstrated that the components of microparticles are released and transferred to albumins and lipid bilayers. The morphology of the measured particulates was studied with the scanning electron microscopy and dynamic light scattering. To determinate the cytotoxicity of microparticles cell culture studies were done. It has been showed that the transfer efficiency depends predominantly on the fatty acid composition of microparticles, which, together with the active ingredient, accumulate predominantly in membrane structures after being released from microparticles and before entering cytoplasm. The release process is sufficient hence paclitaxel-loaded microparticles effectively suppressed the proliferation of A549 human lung epithelial cells of malignant origin (IC50 values for both lauric acid-based and myristic/palmitic-based microparticles containing paclitaxel were below 0.375 µg/ml), while reference microparticles were non-cytotoxic.