"Plurethosome" as Vesicular System for Cutaneous Administration of Mangiferin: Formulative Study and 3D Skin Tissue Evaluation

Abstract

Human skin is dramatically exposed to toxic pollutants such as ozone. To counteract the skin disorders induced by the air pollution, natural antioxidants such as mangiferin could be employed. A formulative study for the development of vesicular systems for mangiferin based on phosphatidylcholine and the block copolymer pluronic is described. Plurethosomes were designed for mangiferin transdermal administration and compared to ethosome and transethosome. Particularly, the effect of vesicle composition was investigated on size distribution, inner and outer morphology by photon correlation spectroscopy, small angle X-ray diffraction, and transmission electron microscopy. The potential of selected formulations as vehicles for mangiferin was studied, evaluating encapsulation efficiency and in vitro diffusion parameters by Franz cells. The mangiferin antioxidant capacity was verified by the 2,2-diphenyl-1-picrylhydrazyl assay. Vesicle size spanned between 200 and 550 nm, being influenced by phosphatidylcholine concentration and by the presence of polysorbate or pluronic. The vesicle supramolecular structure was multilamellar in the case of ethosome or plurethosome and unilamellar in the case of transethosome. A linear diffusion of mangiferin in the case of ethosome and transethosomes and a biphasic profile in the case of plurethosomes indicated the capability of multilamellar vesicles to retain the drug more efficaciously than the unilamellar ones. The antioxidant and anti-inflammatory potential effect of mangiferin against pollutants was evaluated on 3D human skin models exposed to O₃. The protective effect exerted by plurethosomes and transethosomes suggests their possible application to enhance the cutaneous antioxidant defense status.

Keywords: antioxidant; in vitro diffusion; mangiferin; phosphatidylcholine; poloxamer.

Figure 1

Mean diameter of the indicated formulations. Diameters were measured by PCS and expressed as Z average (nm). Data are the mean of three determinations on different samples ± s.d.

Figure 2

Transmission electron microscopy images (TEM) of P7 (a), P9 (b), P11 (c), P12 (d), P13 (e), and P16 (f). Bar corresponds to 200 nm (a,c,d) or 500 nm (b,e,f).

Figure 3

SAXS/WAXS profiles observed at 35 °C. P7 (a), P9 (b), P11 (c), P12 (d), P13 (e), and P16 (f).

Figure 4

MG diffusion kinetics from Sol-MG (closed triangles), P7-MG (open triangles), P9-MG (green circles), P11-MG (red rhombuses), and P12-MG (blue squares), as determined by Franz cell. Experiments were conducted for 6 h (a), with linear profiles within 3 h (b). Data are the mean of 6 independent experiments ± s.d.

Figure 5

Evolution of elastic (G′, blue) and viscous (G″, orange) moduli for P11-MG (a) and P12-MG (b).

Figure 6

(a) Representative images of immunofluorescence staining for 4HNE protein adducts (green) and DAPI (blue) at 40× magnification on 3D skin models treated with P11-MG and P12-MG and exposed to O₃ (b) quantification of immunofluorescence staining of 4HNE protein adducts 0 h and 24 h after O₃ exposure. Data were normalized with respect to the O₃-exposed sample at 0 h and expressed as arbitrary units (%) ± SD. **** p ≤ 0.0001 vs. O₃ at T-0 h. The autofluorescence signal of the 3D skin model inserts was not considered in the quantification analysis.

Figure 7

Levels of IL-1β (pg/mL) in the media of 3D skin models treated with P11-MG and P12-MG analyzed using an IL-1β ELISA kit 0 or 24 h after exposure to O₃ 0.4 ppm for 4 h. Data were normalized with respect to the O₃ sample at 0 h and expressed as arbitrary units (%) ± SD. Data are the results of the averages of at least three different experiments. *** p ≤ 0.001, **** p ≤ 0.0001 vs. O₃ at T 0 h.