Burn wounds are a major clinical concern. According to the WHO, infected burns are among the leading causes of mortality in children.
Although most burn wounds are initially sterile, they commonly become colonized by Gram-positive bacteria within two days. To manage burn wound infections, topical medications with a broad spectrum of antibiotics are used. The most commonly used antibiotic in wound healing is mupirocin . It is effective against Staphylococcus aureus and Staphylococcus epidermidis, the main bacteria causing infection in wounds.
Topical mupirocin formulations are available as hydrogels, nanoemulgels, and macrogol-based formulations. Hydrogels and nanoemulgels exhibit limited drug-loading capacity, poor skin retention, and reduced stability. Macrogol-based formulations can be toxic and require additional precautions when used in patients with extensive burns and wounds.
Researchers from the Sanjivani College of Pharmaceutical Education and Research, Ahmednagar thought of oleogels as an alternative approach for managing topical burn wounds. Oleogels are semisolid formulations consisting of an oil phase structured by an oleogelator. The oleogelator forms aggregates through weak interactions, such as hydrogen bonding and van der Waals forces, resulting in the formation of a three-dimensional network that traps the oil and produces a gel-like structure.
To prepare the oleogel incorporated with mupirocin, the researchers first checked the solubility of mupirocin in sunflower oil, soybean oil, castor oil, coconut oil, peanut oil, olive oil, and sesame oil. They added mupirocin to the different oils and agitated the mixture until equilibrium was reached. The resulting supersaturated solution of oil and mupirocin was then dissolved in methanol and water, a solvent mixture. Since mupirocin absorbs light of 220 nanometres, the researchers used UV spectrophotometry to identify the drug concentration, and thus determined mupirocin’s solubility in each oil. Castor oil showed the highest solubility of mupirocin.
To prepare the oleogel, the researchers added mupirocin to castor oil, dissolved it till equilibrium and transferred the mixture to a beaker. Aerosil, an oleogelator, was then mixed in using a magnetic stirrer till a thick, viscous solution was formed. The researchers heated the solution at 70 ˚C to form a gel which they cooled to room temperature.
To test whether the oleogel containing the antibiotic was safe and non-toxic to skin cells, the researchers evaluated its cytotoxicity on fibroblast cells from mice. The cells were treated with the oleogel formulation to check for cell viability. The oleogel did not have any effect on the fibroblasts.
The researchers then tested the formulation for skin irritation on mice. On one group of mice, they applied the optimized mupirocin oleogel formulation once a day. The other group, the control, was left untreated. The mice were observed for visible symptoms of irritation for three days. No symptoms of irritation, such as redness, erythema, and edema, were observed in the test group.
To test the efficacy of the oleogel, the researchers preheated a stainless-steel rod to 100 ˚C and applied it to the shaved dorsal skin of the mice to create a burn injury. To the injury, the researchers applied mupirocin oleogel daily and observed wound contraction and the healing process.
There was a light yellowish appearance of the skin from day one to day four, followed by scar formation through a transition of the skin colour from light yellow to light brown between the sixth to the fourteenth day. No darkening was observed, indicating the healing of the wound with thickening of the scar tissue. On day sixteen, the scar tissue fell off and the wound appeared red on day seventeen. This redness completely disappeared later. The burn wound was completely healed and hair started growing on the treated mice by day twenty-six. The percentage of wound contraction was 100% in all the mice.
Once a day treatment helps improve patient compliance, especially in children. However, since the researchers used mice, the treatment protocol needs to be developed further in clinical trials.
Journal of Pharmaceutical Innovation, 21: 182 (2026)
DOI: 10.1007/s12247-026-10428-x
Reported by Deepika Baskaran
SASTRA Deemed University, Thanjavur
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