Anti-proliferate and apoptosis triggering potential of methotrexate-transferrin conjugate encapsulated PLGA nanoparticles with enhanced cellular uptake by high-affinity folate receptors.

The objective of the present study is to enhance the permeation of bioactive molecules across highly lipophilic insurmountable blood brain barrier (BBB) using folic acid (FA) functionalized poly(lactic-co-glycolic acid) (PLGA) nanoparticles (FA-PNPs) coated with non-ionic surfactant, Polysorbate 80 (P80). The developed Mtx-Tf loaded folic acid anchored PNPs formulation depicted particle size, zeta potential and entrapment efficiency of 109 ± 2.3 nm, -9.38 ± 0.9 mV and 71.0 ± 0.6%, respectively. In vitro release showed biphasic release pattern with initial >35% release in 8 h followed by sustained release, up to 65% by the end of 168 h. SRB cyto-toxicity assay depicted P80-Mtx-Tf-FA-PNPs possessing better cellular cyto-toxicity (C6 Glioma) as compared to counter test formulations, i.e. 100 μM nano-encapsulated drug-conjugate concentration incubated for 72 h resulted in apoptosis of ∼100% of the cellular population. Qualitatively, ∼85% of P80-FITC-FA-PNPs have been found to be internalized by C6 glioma cells post 5 h of incubation. Quantitative cellular uptake assay demonstrated a collinear dependence on drug-conjugate concentration. In vivo administration of P80-Mtx-Tf-FA-PNPs depicted significant decrease, i.e. 73.6% in the tumour spheroid volume. Serum analysis data pointed towards the significant relevance of P80-coated FA-PNPs in lowering the drug diffusion rate by 88.4% (after 30 min) and three-fold enhanced retention time of drug in systemic circulation, thereby felicitating an effective prognostic treatment. This study clearly demonstrated reduced systemic toxicity, enhanced biocompatibility and anti-tumour efficacy of formulated NPs.