Purpose: Poly(L-lactide-co-glycolide-co-trimethylene carbonate) rods with risperidone and 17-β-estradiol were sterilized by electron beam irradiation. The aim of the study was to assess electron beam irradiation impact on terpolymer composition, chain microstructure, glass transition temperature, molecular weight and the morphological features of rods.
Methods: Hot melt extrusion in the formulation of rods was applied. Sterilization of the rods was performed by electron beam in an electron beam accelerator (10 MeV, 360 mA, 25 kGy). The following methods in the development of rods were applied: nuclear magnetic resonance, differential scanning calorimetry, gel permeation chromatography and scanning electron microscopy.
Results: Sterilization influenced only glass transition temperature in blind rods and rods with risperidone. As for the other parameters, no significant changes were observed as far as a sterilization effect is concerned. However, some changes were noted after introducing drug substances and after extrusion.
Conclusions: Electron beam irradiation of rods with risperidone and rods with 17-β-estradiol is an adequate method for sterilizing implantable drug delivery systems.