Effect of E-Beam Irradiation on Solutions of Fullerene C60 Conjugate with Polyvinylpyrrolidone and Folic Acid.

The radiation sterilization of polymer-based drug solutions can change the characteristics that determine the efficiency of drug targeting, such as particle sizes in the solution and their surface potential. The effect of E-beam treatment at doses of 3 and 8 kGy in a Xe or air atmosphere on the hydrodynamic properties of dilute solutions of polyvinylpyrrolidone (PVP) conjugate with fullerene C60 and folic acid (FA-PVP-C60) was studied and compared with native PVP K30. The capillary viscometry method was used to determine the intrinsic viscosity of solutions. The particle sizes (Rh) were determined using the DLS method. The zeta potential of the particles was determined using the PALS method. The morphological features of the conjugate surface irradiated in a Xe atmosphere with a dose of 8 kGy FA-PVP-C60 were studied by AFM. The functionalization of FA-PVP-C60 and PVP during E-beam treatment was examined using UV- and FTIR-spectrometry. When the diluted solutions of FA-PVP-C60 and PVP were irradiated in air with a dose of 3 kGy, destruction of polymer chains occurred predominantly, but when the dose was increased to 8 kGy, intermolecular cross-linking occurred, leading to an increase in the characteristic viscosity and particle size in the solution. It was shown that the average particle sizes, amounting to 3 and 8 nm for PVP and 4 and 20 nm for FA-PVP-C60, did not change significantly under E-beam irradiation in a Xe atmosphere in the considered dose range. The zeta potential of the particles remained virtually unchanged for both PVP and FA-PVP-C60 under all irradiation conditions. The obtained results indicate the possibility of performing radiation sterilization of FA-PVP-C60 conjugate solutions in an inert gas atmosphere in the range of studied doses.