Doxorubicin-Loaded Poly(Substituted Glycolide)-Based Nanoparticles for Long-Term Storage

Preventing agglomeration is crucial for polymeric nanoparticles (PNP) for drug-delivery applications. Suitable conditions for maintaining the size of doxorubicin (DOX)-loaded poly-(diisobutyl glycolide) (PDIBG) and poly-(diisopropyl glycolide) (PDIPG) nanoparticles (NP) during long-term storage were investigated in this study. After the synthesis of PDIBG and PDIPG homopolymers, DOX-loaded NPs were produced from these homopolymers by using a single-emulsion solvent evaporation method. The optimal formulations of DOX-loaded PDIBG and PDIPG-NPs were obtained with particle sizes of 253 ± 7 nm, PDIs of 0.06 ± 0.02, and an EE value of 58.3%, and particle sizes of 253 ± 7 nm, PDIs of 0.08 ± 0.04, and an EE value of 73.9%, respectively. To extend their shelf life, the developed NPs at three different concentrations (50, 70, and 90 mg/mL) were subjected to a comprehensive lyophilization process at two different freezing temperatures (-20 and -50 °C). As a result of the systematic lyophilization of sugar-containing and sugar-free formulations of DOX-loaded PDIBG and PDIPG-NPs under specific conditions, it was found that they could be stored at 4 and -20 °C for 2 months while maintaining their particle sizes and PDI values in the presence of glucose and sucrose (at 5 and 10% concentrations).