Development and Pharmaceutical Evaluation of Azelaic Acid and Vitamin E Oil-Based Nanoemulgel of Tacrolimus for Topical Application in Plaque Psoriasis

PurposePsoriasis is characterized by moisture- and lipid-deficient skin with an elevated epidermal keratinocyte hyperproliferation rate due to diminished p53 levels. Topical therapy with available tacrolimus ointment in such cases is very limited, ensuing to its less penetrability (thickened skin) and availability (moisture and lipid deficiency), thereby restricting its use.MethodsTherefore, we developed and evaluated a lipid nanoemulsion-based gel comprised of azelaic acid and tacrolimus (ATNEG) meant for topical administration to improve the availability of the drug at the local site and its efficacy against plaque psoriasis.ResultsThe optimized nanoemulsion with droplet size (262.6 +/- 9.2 nm) and uniform size distribution (PDI; 0.251 +/- 0.03) was thickened with the help of Carbopol 940 for improved residence time over the diseased site. The pH of the developed gel was close to the skin's pH, and the gel was observed to possess all the desirable characteristics essential for topical application. Nanoemulgel showed a controlled drug release profile (83.7% in 12 h) and very slow permeation (38.8% in 24 h) through the skin, which is expected to ensure consistent drug availability on the skin for absorption and, thereby, high dermal retention of the drug for an extended period when compared with the marketed tacrolimus ointment (Tac-Oint).ConclusionAlthough the base of the gel is hydrous, it portrays immense utility in maintaining the skin's moisture level with efficient drug penetration and localization. The developed formulation promises to be a potential candidate for treating plaque psoriasis.