Activity of hydrogel-vitamin D3 /bacterioruberin nanoparticles on imiquimod-induced fibroblasts-keratinocytes spheroids.

Topical administration of vitamin D3 (VD3) analogs and corticosteroids is the mainstay treatment for mild localized psoriasis. VD3 however is an unstable class II drug (insoluble and permeable), classically formulated as unattractive viscous and oil-based ointments or creams. In this work, nanostructured archaeolipid carriers (NAC) with a core loaded with VD3 and the C50 dipolar carotenoid from halophilic archaea bacterioruberin (BR): NAC-VD3, were formulated into a carbopol hydrogel: gNAC-VD3. After its rheological characterization, its anti-inflammatory and antioxidant activity was assessed on bi-cellular spheroids, consisting of a core of fibroblasts surrounded by a ring of keratinocytes activated with imiquimod (IMQ) as a psoriasis model. gNAC-VD3 (0.8 mg VD3/ 135 μg BR/gram gel) conserved the antioxidant activity, showed pseudoplastic non-Newtonian behaviour, stability over time, good occlusion capacity and spreadability, all suitable properties for topical application in patients with psoriasis. gNAC-VD3 did not decrease the viability of spheroids but significantly reduced the release of proinflammatory cytokines (IL-8, IL-6, TNF-α), oxidative stress (ROS), and matrix metalloproteinases from IMQ-induced spheroids to levels similar to the uninduced spheroids. Results suggest that gNAC-VD3 may constitute a potential anti-inflammatory agent for the topical treatment of mild psoriasis and deserves further in vivo exploration.