The Effects of Storage Conditions on the Stability of Porcine Placenta Extract-loaded Liposome Formulations

We aimed to evaluate the effect of temperature, pH, and light conditions on the stability of porcine placental extract (PPE)-loaded liposomes with different surface charges. The size distribution profiles and in vitro release patterns were investigated by dynamic light scattering method and spectrophotometry. The stability of PPE-loaded liposomes was affected by the surface charges of the liposomes. As compared to neutral and anionic liposomes, cationic liposome formulations showed significantly lower physical stability. At the test storage conditions of different temperatures and pHs, the mean sizes of cationic PPE-loaded liposomes substantially increased. In contrast, neutral and anionic liposomes did not reveal significant changes in mean sizes upon various storage conditions. The neutral and anionic liposomes showed no significant differences in the release profiles of PPE after storage at various temperatures and pHs. Our results indicate that anionic and neutral liposome compositions might be more suitable for the formulations of PPE providing the higher stability.