Wound healing efficacy of a curcumin emulgel enriched with camphor-menthol-based deep eutectic solvent (CM-NADES)

Turmeric, a rhizomatous plant, contains curcumin, which is responsible for its yellow hue and various pharmacological activities such as anti-bacterial, anti-inflammatory wound healing, etc. However, curcumin’s pharmacological activities heavily hampered due to its low aqueous solubility (7.80 µg/mL), and poor bioavailability (0.051 µg/L). This investigation explores the possibility of developing topical emulgel formulation based on carbopol and neoteric solvent like camphor menthol based natural hydrophobic deep eutectic solvent. Keeping the camphor-menthol, tween-80, glycerin and water at the constant values of 5% w/w (1:1), 5–8% w/w, 5% w/v and 83–84% w/w respectively, the carbopol amount were varied from 0.5 to 1.1% w/v to prepare emulgel for healing the wound in excision induced Wistar rat. The developed emulgel was evaluated for appearance, pH, viscosity, centrifugation test, spreadability and curcumin content. With 1% carbopol based emulgel, the in vitro curcumin release was found to be 22.42 ± 1.78% over the period of 24 h. The ex vivo skin permeation study using pig ear skin indicated the 3.70 ± 0.14% of curcumin was permeated inside the pig skin at 24 h. Dermal pharmacokinetics by tape stripping technique showed that 64.79 ± 3.25% of curcumin was present in the viable layer and 27.29 ± 2.21% was present in the stratum corneum layer. The once daily application of Cur-EMG-T-7 and the marketed formulation in excised Wistar rat produced a comparable wound healing activity (On 20th day) in terms wound closures are confirmed in histopathological analyzers. Overall, the Cur-EMG-T-7 emulgel could be projected as an alternative topical gel in healing the wounds produced at excision, skin burning, accidental skin crap, surgical wound, etc.