Lyoprotected nanosphere formulations for paclitaxel controlled delivery

The preparation and technological characterization of nanosphere formulations (NS) containing the anticancer drug paclitaxel (PTX) are reported. Poly(lactide) (PLA) and poly(lactide-co-glycolide) (PLGA) nanospheres (NS) were prepared by a solvent displacement method. They showed a mean particle size in the range 150-300 nm, with a high homogeneity (polydispersity index < 0.3). For long term stability, NS require additional procedures, such as freeze-drying. In this study, the effect on NS particle size and surface charge of different lyoprotectants (mono- and disaccharides, polyalcohols, and hydroxypropyl-beta-cyclodextrin) at various concentrations was tested by means of light scattering size analysis. The formulations freeze-dried with the addition of 10% glucose (w/v) showed interesting characteristics after freeze-drying. They were chosen for specific studies on drug encapsulation efficiency, in vitro drug release and biological activity on the human anaplastic thyroid carcinoma cell line 8305C. The PLGA NS, in particular, showed a cell growth inhibitory activity comparable to the free drug.