Original Articles

Effect of MePEG molecular weight and particle size on in vitro release of tumor necrosis factor-α-loaded nanoparticles

Chao FANG, Bin SHI, Yuan-ying PEI


Aim: To study the in vitro release of recombinant human tumor necrosis factoralpha
(rHuTNF-α) encapsulated in poly (methoxypolyethyleneglycol cyanoacrylate-
co-n-hexadecyl cyanoacrylate) (PEG-PHDCA) nanoparticles, and investigate
the influence of methoxypolyethyleneglycol (MePEG) molecular weight and particle
Methods: Three sizes (approximately 80, 170, and 240 nm) of PEGPHDCA
nanoparticles loading rHuTNF-α were prepared at different MePEG molecular
weights (Mr =2000, 5000, and 10 000) using the double emulsion method.
The in vitro rHuTNF-α release was studied in PBS and rat plasma.
Results: A
higher burst-release and cumulative-release rate were observed for nanoparticles
with higher MePEG molecular weight or smaller particle size. A decreased cumulative
release of rHuTNF-α following the initial burst effect was found in PBS,
while the particle sizes remained constant and MePEG liberated. In contrast, in
rat plasma, slowly increased cumulative-release profiles were obtained after the
burst effect. During a 5-h incubation in rat plasma, more than 50% of the PEGPHDCA
nanoparticles degraded.
Conclusion: The MePEG molecular weight
and particle size had an obvious influence on rHuTNF-α release. rHuTNF-α
released from PEG-PHDCA nanoparticles in a diffusion-based pattern in PBS,
but in a diffusion and erosion-controlled manner in rat plasma.