Stealth® liposomal tumor necrosis factor-α in solid tumor treatment

Enhancing electroporation-induced liposomal drug release in suspension and solid phases

When exposed to an external electric field, lipid bilayer membranes are subject to increased permeability through the generation of pores. Combining this phenomenon, known as electroporation, with liposomal drug delivery offers the added benefit of on-demand release of the liposomal cargo. In previous studies, the maximum percent drug release when exposing liposomes to a pulsed electric field has not surpassed 30%, indicating most of the drug is still retained in the liposomes. Here we showed that by modulating the fluidity of the liposome membrane through appropriate selection of the primary lipid, as well as the addition of other fluidity modulating components such as cholesterol and biotinylated lipid, the electroporation-induced percent release could be increased to over 50%. In addition to improved induced release from liposomes in suspension, biomaterial scaffold-bound liposomes were developed. Electroporation-induced protein release from this solid phase was verified after performing further optimization of the liposome formulation to achieve increased stability at physiological temperatures. Collectively, this work advances the ability to achieve efficient electroporation-induced liposomal drug delivery, which has the potential to be used in concert with other clinical applications of electroporation, such as gene electrotransfer and irreversible electroporation (IRE), in order to synergistically increase treatment efficacy.

Stealth polycyanoacrylate nanoparticles as tumor necrosis factor-alpha carriers: pharmacokinetics and anti-tumor effects

The objective of this study was to investigate the pharmacokinetics and in vivo anti-tumor effect of recombinant human tumor necrosis factor-alpha (rHuTNF-alpha) encapsulated in poly(methoxypolyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEG-PHDCA) nanoparticles. Our experimental results showed that PEG-PHDCA nanoparticles could extend the half-life of rHuTNF-alpha to 7.42 h and obviously change the protein biodistribution in tissues, and in particular, increase accumulation of rHuTNF-alpha in tumor. Compared with PHDCA nanoparticles and free rHuTNF-alpha, PEG-PHDCA nanoparticles loaded with rHuTNF-alpha showed higher antitumor potency at the same dose, which might be related to its higher accumulation in tumor tissues and longer plasma circulation time. Therefore, PEG-PHDCA nanoparticles could be an effective carrier for rHuTNF-alpha.

PEGylated polycyanoacrylate nanoparticles as tumor necrosis factor-alpha carriers

The aim of this study was to find an effective carrier for recombinant human tumor necrosis factor-alpha (rHuTNF-alpha). The influence of solvent systems containing poly(methoxy-polyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEGylated PHDCA) on the biological activity of rHuTNF-alpha was investigated. The PEGylated PHDCA nanoparticles loading rHuTNF-alpha were prepared with the double emulsion method. The influence of main experimental factors on the entrapment efficiency was evaluated by the Uniform Design. The physicochemical characteristics and in vitro release of rHuTNF-alpha from the nanoparticles were determined. The results showed that serum albumin such as human serum albumin (HSA) or bovine serum albumin (BSA) could play a protective action on rHuTNF-alpha in the preparation process. At > or =2.0% (w/v) HSA concentration, more than 85% of rHuTNF-alpha activity remained and the role of HSA was not affected by copolymer concentrations from 0.5 to 3.0% (w/v). The entrapment efficiency of the nanoparticles was about 60% and the nanoparticle size was about 150 nm. The nanoparticles were spherical in shape and uniform with the value of the zeta potential about -9 mV. The rHuTNF-alpha release from the nanoparticle showed an initial burst and then continued in a sustained fashion. The results showed that the PEGylated PHDCA nanoparticles could be an effective carrier for rHuTNF-alpha.