Preparation, characterization, cytotoxicity and pharmacokinetics of niosomes containing gemcitabine: In vitro, in vivo, and simulation studies

Novel niosomes including cholesterol, Span (60), Tween (60), and gemcitabine (GEM) have been developed via film hydration approach and characterized via in vitro, in vivo, and in silico experiments. They showed a nanometric size, spherical morphology, a controlled drug release (50% after 48 h) and significantly lower IC50 values in SH-SY5Y and MCF7 cancerous cell lines than the free GEM, the lowest value being 19.70 ng/mL in SH-SY5Y cells. Annexin V/PI double staining results demonstrated that the main mechanism for cell-killing effects of niosomal GEM is apoptosis; however, 18.31% of MCF7 cells underwent necrosis. Intravenous treatments of rats with niosomal GEM at 0.1 and 0.2 mg/kg body weight (bw) significantly increased biochemical parameters (i.e., serum alanine aminotransferase, serum creatinine, blood urea nitrogen, aspartate aminotransferase, and liver malondialdehyde), and caused severe histopathological alterations. Conversely, the same concentration of free GEM did not alter these parameters. Molecular dynamics simulations and umbrella sampling were used to investigate the interactions between GEM and Span 60, Tween 60, and cholesterol molecules at the interface of the niosome bilayer and while diffusing through. They demonstrated four energy barriers preventing GEM from permeating the membrane, ascribed to electrostatic and H-bonding interactions between polar groups in the drug and all the species inside the membrane. The developed niosomes might have great potential to serve as suitable carriers for particular chemotherapeutic agents, thereby reducing their side effects. Future work will focus on evaluating their safety towards normal human cells.