Folic acid-functionalized drug delivery platform of resveratrol based on Pluronic 127/D-α-tocopheryl polyethylene glycol 1000 succinate mixed micelles

Abstract

A folic acid (FA)-functionalized drug vehicle platform based on Pluronic 127 (P127)/D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) mixed micelles was orchestrated for an effective delivery of the model drug resveratrol in order to address the problem of poor water solubility and rapid metabolism of resveratrol and improve its targeted accumulation at tumor site. The FA-decorated mixed micelles were prepared using thin-film hydration method and optimized by central composite design approach. The micelles were also characterized in terms of size and morphology, drug entrapment efficiency and in vitro release profile. In addition, the cytotoxicity and cell uptake of the micelles were evaluated in folate receptor-overexpressing MCF-7 cell line. In vivo pharmacokinetic and biodistribution studies were also performed. The average size of the micelles was ~20 nm with a spherical shape and high encapsulation efficiency (99.67%). The results of fluorescence microscopy confirmed the targeting capability of FA-conjugated micelles in MCF-7 cells. FA-modified micelles exhibited superior pharmacokinetics in comparison with that of solution. Further, the low accumulation of resveratrol-loaded FA micelles formulation in the heart and kidney avoided toxicity of these vital organs. It could be concluded that folate-modified P127/TPGS mixed micelles might serve as a potential delivery platform for resveratrol.

Keywords: Pluronic 127/TPGS; folic acid conjugation; mixed micelles; resveratrol.

Figure 1

Schematic illustration of the synthesis routes of FA-P127. Abbreviations: P127, Pluronic 127; CDI, 1,1-carbonyldiimidazole; DCC, 1,3-dicyclohexyl-carbodiimide; NHS, N-hydroxysuccinimide; FA, folic acid.

Figure 2

The physicochemical characteristics of functional FA-P127: ¹H NMR spectrum of FA-P127 (A); IR spectrum of P127 (B); IR spectrum of FA (C); FTIR spectrum of FA-P127 (D); and UV spectrum of FA, P127 and FA-P127 (E). Abbreviations: FA, folic acid; P127, Pluronic 127; ¹H NMR, proton nuclear magnetic resonance; IR, infrared; FTIR, Fourier transform infrared; UV, ultraviolet.

Figure 2

The physicochemical characteristics of functional FA-P127: ¹H NMR spectrum of FA-P127 (A); IR spectrum of P127 (B); IR spectrum of FA (C); FTIR spectrum of FA-P127 (D); and UV spectrum of FA, P127 and FA-P127 (E). Abbreviations: FA, folic acid; P127, Pluronic 127; ¹H NMR, proton nuclear magnetic resonance; IR, infrared; FTIR, Fourier transform infrared; UV, ultraviolet.

Figure 3

Response surface model showing the influence of the independent variables on the EE (A), DL (B) and particle size (C). Abbreviations: EE, encapsulation efficiency; P127, Pluronic 127; TPGS, D-α-tocopheryl polyethylene glycol 1000 succinate; DL, drug loading.

Figure 4

The physicochemical characteristics of FA-P127/TPGS micelles: particle size and size distribution (A); TEM morphology images (B) and determination of CMC value of the micelles (C). Abbreviations: FA, folic acid; P127, Pluronic 127; TPGS, D-α-tocopheryl polyethylene glycol 1000 succinate; TEM, transmission electron microscopy; CMC, critical micelle concentration.

Figure 5

Profiles of the cumulative release percentage of resveratrol from mixed micelles and the polyethylene glycol solution.

Figure 6

In vitro cell line evaluation: in vitro cytotoxicity of micelles in MCF-7 cells (A); fluorescence microscopic images of micelles internalized (B) and cell uptake efficiency of micelles (C). *P<0.05, **P<0.01. Abbreviations: FA, folic acid; P127, Pluronic 127.

Figure 7

Plasma concentration versus time profile of resveratrol after i.v. administration (A) and biodistribution of resveratrol after i.v. administration (B). Abbreviations: i.v., intravenous; PEG, polyethylene glycol.