Supramolecular and Macromolecular Matrix Nanocarriers for Drug Delivery in Inflammation-Associated Skin Diseases

Hyaluronan-Cholesterol nanogels embedding betamethasone for the treatment of skin inflammatory conditions

Topical application of the glucocorticoid betamethasone (BM) is a common treatment for inflammatory-related skin diseases, such as psoriasis. However, enhancing its bioavailability remains challenging due to poor skin permeability. Herein, we developed and evaluated hyaluronan-cholesterol (HACH) based nanohydrogel systems (NHs) and NHs-Carbopol formulation for dermal delivery of BM. Various parameters were investigated including particle size, surface charge, encapsulation efficiency, in vitro drug release kinetics and stability. The HACH-based NHs demonstrated high encapsulation efficiency, with apparent solubility improved up to 9-fold, small size (∼190 nm) and good stability at 4 ℃ and during long-term storage. Besides, the NHs-Carbopol formulation exhibited excellent rheological properties and an occlusive effect suitable for cutaneous application. Both in-vitro (using Strat-M® membrane) and ex-vivo (using pig ear skin) permeation studies revealed that these formulations significantly improved skin permeation and drug retention in the deeper layers of the epidermis and dermis, making it advantageous for the topical delivery of BM in psoriasis treatment. Moreover, the NHs system demonstrated potential anti-psoriatic activity by downregulating the proinflammatory cytokines in vitro in human keratinocytes (HaCaT cell line) and in an ex vivo 3D skin tissue model (EpiDerm-FT™).

The Association of Oleic Acid and Dexamethasone Acetate into Nanocapsules Enables a Reduction in the Effective Corticosteroid Dose in a UVB Radiation-Induced Sunburn Model in Mice

Dexamethasone has a high anti-inflammatory efficacy in treating skin inflammation. However, its use is related to the rebound effect, rosacea, purple, and increased blood glucose levels. Nanotechnology approaches have emerged as strategies for drug delivery due to their advantages in improving therapeutic effects. To reduce dexamethasone-related adverse effects and improve the anti-inflammatory efficacy of treatments, we developed nanocarriers containing this corticosteroid and oleic acid. Nanocapsules and nanoemulsion presented dexamethasone content close to the theoretical value and controlled dexamethasone release in an in vitro assay. Gellan gum-based hydrogels were successfully prepared to employ the nanostructured systems. A permeation study employing porcine skin showed that hydrogels containing non-nanoencapsulated dexamethasone (0.025%) plus oleic acid (3%) or oleic acid (3%) plus dexamethasone (0.025%)-loaded nanocapsules provided a higher amount of dexamethasone in the epidermis compared to non-nanoencapsulated dexamethasone (0.5%). Hydrogels containing oleic acid plus dexamethasone-loaded nanocapsules effectively inhibited mice ear edema (with inhibitions of 89.26 ± 3.77% and 85.11 ± 2.88%, respectively) and inflammatory cell infiltration (with inhibitions of 49.58 ± 4.29% and 27.60 ± 11.70%, respectively). Importantly, the dexamethasone dose employed in hydrogels containing the nanocapsules that effectively inhibited ear edema and cell infiltration was 20-fold lower (0.025%) than that of non-nanoencapsulated dexamethasone (0.5%). Additionally, no adverse effects were observed in preliminary toxicity tests. Our study suggests that nanostructured hydrogel containing a reduced effective dose of dexamethasone could be a promising therapeutic alternative to treat inflammatory disorders with reduced or absent adverse effects. Additionally, testing our formulation in a clinical study on patients with skin inflammatory diseases would be very important to validate our study.