Effects of PEG surface density and chain length on the pharmacokinetics and biodistribution of methotrexate-loaded chitosan nanoparticles.

Background: One of the most important aspects of drug delivery is extended nanoparticle (NP) residence time in vivo. Herein, we report a series of methotrexate (MTX)-loaded chito-san (CS) NPs coated with differently sized methoxy polyethylene glycol (mPEG) at different mPEG surface densities.

Materials and methods: MTX was incorporated into NPs (112.8-171.2 nm in diameter) prepared from the resulting mPEG-g-CS. The NPs had a zeta potential of +7.4-35.0 mV and MTX loading efficiency of 17.1%-18.4%. MTX/mPEG-g-CS NPs showed an initial burst release of MTX followed by a sustained-release profile in PBS at pH 7.4.

Results: The in vitro cellular uptake study showed that MTX accumulation in J774A.1 macrophage cells decreased with increasing the mPEG surface density or the mPEG molecular weight. The pharmacokinetic study on Sprague Dawley rats revealed an increase in AUC0-72 h (area under the plasma drug concentration-time curve over a period of 72 hours) with increasing the mPEG surface density or the mPEG molecular weight and a linear correlation between the mPEG surface density and AUC0-72 h .

Conclusion: The biodistribution study on Institute of Cancer Research (ICR) mice revealed that MTX/mPEG-g-CS NPs significantly enhanced blood circulation time in the body and decreased accumulation in liver, spleen, and lung. These results suggest the potential of the mPEG-g-CS NPs as a promising candidate for drug delivery.