Transdermal Permeation Assays of Curcumin Aided by CAGE-IL: In Vivo Control of Psoriasis

Abstract

Psoriasis is a clinically heterogeneous skin disease with an important genetic component, whose pathophysiology is not yet fully understood and for which there is still no cure. Hence, alternative therapies have been evaluated, using plant species such as turmeric (Curcuma longa Linn.) in topical preparations. However, the stratum corneum is a barrier to be overcome, and ionic liquids have emerged as potential substances that promote skin permeation. Thus, the main objective of this research was to evaluate a biopolysaccharide hydrogel formulation integrating curcumin with choline and geranic acid ionic liquid (CAGE-IL) as a facilitator of skin transdermal permeation, in the treatment of chemically induced psoriasis in mice. The developed gel containing curcumin and CAGE-IL showed a high potential for applications in the treatment of psoriasis, reversing the histological manifestations of psoriasis to a state very close to that of normal skin.

Keywords: choline and geranic acid ionic liquid; curcumin; in vivo assays; psoriasis; transdermal permeation.

Figure 1

Differential scanning calorimetry thermograms of CAGE-IL (grey line), pure CUR (orange line), commercial turmeric (purple line), LBG gel formulation integrating pure CUR (blue line), LBG gel formulation integrating pure CUR and CAGE-IL (red line) and LBG gel formulation integrating commercial turmeric and CAGE-IL (green line).

Figure 2

Results obtained after application of the formulations in the ears of male mice. (a) (G2) 10 days of LBG (2%, w/w) gel application; (b) (G2) 20 days of LBG (2%, w/w) gel application; (c) (G3) 10 days of application of LBG gel (2%, w/w) with CUR (2%, w/w); (d) (G3) 20 days of application of LBG gel (2%, w/w) with CUR (2%, w/w); (e) (G4) 10 days of application of LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w); (f) (G4) 20 days of application of LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w); (Æ-m) (G1) photomicrograph (x200 magnification) of histological section of mouse ear skin of male absolute control; (b1) (G2) photomicrograph (×200 magnification) of histological section of mouse ear skin after 20 d of application of LBG gel (2%, w/w); (d1) (G3) photomicrograph (×200 magnification) of histological section of mouse ear skin after 20 d of application of LBG gel (2%, w/w) with CUR (2%, w/w); (f1) (G4) photomicrograph (×200 magnification) of histological section of mouse ear skin after 20 d of application of LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w). The histological sections were stained with hematoxylin and eosin. For the significance of the inserted (thick, thin and arrowhead) arrows, please refer to the Discussion section. Scale bar represents 50 µm. Note: the yellowish color observed in the fur of the animals is due to the use of the gel with CUR and CAGE-IL, with the ionic liquid promoting a greater solubility of CUR and consequently dying the fur.

Figure 3

Results obtained after application of the formulations in the ears of female mice. (a) (G2) 10 days of LBG (2%, w/w) gel application; (b) (G2) 20 days of LBG (2%, w/w) gel application; (c) (G3) 10 days of application of LBG gel (2%, w/w) with CUR (2%, w/w); (d) (G3) 20 days of application of LBG gel (2%, w/w) with CUR (2%, w/w); (e) (G4) 10 days of application of LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w); (f) (G4) 20 days of application of LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w); (Æ-f) (G1) photomicrograph (×200 magnification) of histological section of mouse ear skin of female absolute control; (b1) (G2) photomicrograph (×200 magnification) of histological section of mouse ear skin after 20 d of application of LBG gel (2%, w/w); (d1) (G3) photomicrograph (×200 magnification) of histological section of mouse ear skin after 20 d of application of LBG gel (2%, w/w) with CUR (2%, w/w); (f1) (G4) photomicrograph (×200 magnification) of histological section of mouse ear skin after 20 d of application of LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w). The histological sections were stained with hematoxylin and eosin. For the significance of inserted (thick, thin and arrowhead) arrows, please refer to the Discussion section. Scale bar represents 50 µm. Note: the yellowish color observed in the fur of the animals is due to the use of the gel with CUR and CAGE-IL, with the ionic liquid promoting a greater solubility of CUR and consequently dying the fur.

Figure 4

Results obtained for the evolution of the thickness of the ears of the animals in the control groups, during 20 d of application of LBG gel (2%, w/w), LBG gel (2%, w/w) with CUR (2%, w/w) and LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w). (a) Male mice (p > 0.05) and (b) female mice (p > 0.05). The results displayed are the average of three determinations, and the error bars represent the standard deviations.

Figure 5

Results obtained after IMQ-induced psoriasis and application of the formulations in the ears of male mice. (a) (G5) 10 days of application of IMQ; (b) (G5) natural recovery of the mouse ears without treatment; (c) (G6) 10 days of application of IMQ; (d) (G6) 10 days of application of LBG (2%, w/w) gel; (e) (G7) 10 days of application of IMQ; (f) (G7) 10 days of application of LBG gel (2%, w/w) with CUR (2%, w/w); (g) (G8) 10 days of application of IMQ; (h) (G8) 10 days of application of LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w); (b1) (G5) photomicrograph (×200 magnification) of histological section of mouse ear skin after 20 d of natural recovery of IMQ-induced psoriasis; (d1) (G6) photomicrograph (×200 magnification) of histological section of mouse ear skin with IMQ-induced psoriasis after 20 d of application of LBG gel (2%, w/w); (f1) (G7) photomicrograph (×200 magnification) of histological section of mouse ear skin with IMQ-induced psoriasis after 20 d of application of LBG gel (2%, w/w) with CUR (2%, w/w); (h1) (G8) photomicrograph (×200 magnification) of histological section of mouse ear skin with IMQ-induced psoriasis after 20 d of application of LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w). All histological sections were stained with hematoxylin and eosin. For the significance of inserted (thick, thin and arrowhead) arrows, please refer to the Discussion section. Scale bar represents 50 µm. Note: the yellowish color observed in the fur of the animals is due to the use of the gel with CUR and CAGE-IL, with the ionic liquid promoting a greater solubility of CUR and consequently dying the fur.

Figure 6

Results obtained after IMQ-induced psoriasis and application of the formulations in the ears of female mice. (a) (G5) 10 days of application of IMQ; (b) (G5) natural recovery of the mouse ears without treatment; (c) (G6) 10 days of application of IMQ; (d) (G6) 10 days of application of LBG (2%, w/w) gel; (e) (G7) 10 days of application of IMQ; (f) (G7) 10 days of application of LBG gel (2%, w/w) with CUR (2%, w/w); (g) (G8) 10 days of application of IMQ; (h) (G8) 10 days of application of LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w); (b1) (G5) photomicrograph (×200 magnification) of histological section of mouse ear skin after 20 d of natural recovery of IMQ-induced psoriasis; (d1) (G6) photomicrograph (x200 magnification) of histological section of mouse ear skin with IMQ-induced psoriasis after 20 d of application of LBG gel (2%, w/w); (f1) (G7) photomicrograph (×200 magnification) of histological section of mouse ear skin with IMQ-induced psoriasis after 20 d of application of LBG gel (2%, w/w) with CUR (2%, w/w); (h1) (G8) photomicrograph (×200 magnification) of histological section of mouse ear skin with IMQ-induced psoriasis after 20 d of application of LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w). All histological sections were stained with hematoxylin and eosin. For the significance of inserted (thick, thin and arrowhead) arrows, please refer to the Discussion section. Scale bar represents 50 µm. Note: the yellowish color observed in the fur of the animals is due to the use of the gel with CUR and CAGE-IL, with the ionic liquid promoting a greater solubility of CUR and consequently dying the fur.

Figure 7

Boxplot graphs of the evolution of erythema (a,b) and ear skin peeling (c,d) in male (a,c) (p < 0.001) and female (b,d) (p < 0.001) mice. Legend: (🞵) represent outlier points off the average values.

Figure 8

Boxplot graphs of the evolution of erythema (a,b) and ear skin peeling (c,d) induced by imiquimod (IMQ) and the comparison of the remission obtained via application of the treatments with the LBG gel formulations in male (a,c) (p < 0.001) and female (b,d) (p < 0.001) mice. Legend: (🞵) represent outlier points off the average values.

Figure 9

Results obtained for the thickness of the epidermis of the ears of the animals in the control and treatment groups, after 20 d of application of LBG gel (2%, w/w), LBG gel (2%, w/w) with CUR (2%, w/w) and LBG gel (2%, w/w) with CUR (2%, w/w) and CAGE-IL (2%, w/w), and after 10 d following induction of psoriasis with IMQ. (a) Male mice (p > 0.05) and (b) female mice (p > 0.05). The results displayed are the averages of three determinations and the error bars represent the standard deviations. The data were statistically analyzed via one-way ANOVA, and * represents a statistically significant result compared with the control group (without treatment, black columns).