Pranoprofen (PRA)-loaded nanostructured lipid carriers (NLC) have been dispersed into blank gels composed of 1% of Carbomer 940 (PRA-NLC-Car) and 3% of Sepigel^® 305 (PRA-NLC-Sep) as a novel strategy to refine the biopharmaceutical profile of PRA, for dermal administration in the treatment of skin inflammation that may be caused by possible skin abrasion. This stratagem intends to improve the joining of PRA with the skin, improving its retention and anti-inflammatory effect. Gels were evaluated for various parameters such as pH, morphology, rheology, and swelling. In vitro drug release research and ex vivo permeation through the skin were carried out on Franz diffusion cells. Additionally, in vivo assays were carried out to evaluate the anti-inflammatory effect, and tolerance studies were performed in humans by evaluating the biomechanical properties. Results showed a rheological profile common of semi-solid pharmaceutical forms for dermal application, with sustained release up to 24 h. In vivo studies using PRA-NLC-Car and PRA-NLC-Sep in Mus musculus mice and hairless rats histologically demonstrated their efficacy in an inflammatory animal model study. No signs of skin irritation or modifications of the skin’s biophysical properties were identified and the gels were well tolerated. The results obtained from this investigation concluded that the developed semi-solid formulations represent a fitting drug delivery carrier for PRA’s transdermal delivery, enhancing its dermal retention and suggesting that they can be utilized as an interesting and effective topical treatment for local skin inflammation caused by a possible abrasion.

Mild to moderate pain for a few hours to several days post-piercing is normal, and the pain is usually accompanied by swelling, redness, and warmth due to the inflammatory response. Cool compresses and over-the-counter analgesics (e.g., NSAIDs) can ease mild discomfort. However, oral NSAIDs may have systemic side effects; for this reason, we propose a topical anti-inflammatory approach. Four pranoprofen-loaded gels were created using different gelling agents: Sepigel^® 305 (PF-Gel-Sep), Carbopol^® 940 (PF-Gel-Car), Pluronic^® F-68 (PF-Gel-Plu), and Lutrol^® F-127 (PF-Gel-Lut). The gels were assessed for pH, morphology, FT-IR spectroscopy, rheological properties, spreadability, swelling and degradation, drug release kinetics, skin permeation (cow and human skin), irritation potential (HET-CAM assay), and impact on skin barrier function (TEWL and SCH). The gels exhibited varied rheological properties with PF-Gel-Car showing high viscosity and PF-Gel-Plu very low viscosity. All gels had similar spreadability with PF-Gel-Lut showing the highest. PF-Gel-Car showed the highest amounts of PF released, whereas PF-Gel-Plu led to the highest amount of pranoprofen retained in human and bovine skin. The HET-CAM assay indicated that none of the PF-Gels were irritating. Additionally, PF-Gel-Car and PF-Gel-Plu showed no cytotoxic effects on HaCaT cells. In vivo testing on mice showed that PF-Gel-Car prevented inflammation, while the rest of the gels were able to revert it in 25 min. Skin tolerance tests revealed the gels did not affect TEWL, and some gels improved SCH. The study successfully formulated and characterized four PF-loaded topical gels with potential to be used as an alternative for treating inflammation from piercings and ear tags.