The findings suggested that the patch could offer a safer, more effective topical treatment for common inflammatory skin disorders including acne, dermatitis, and psoriasis.
This also presents an opportunity to move away from existing treatments that often cause unwanted side effects.
This new delivery system, detailed in a study by researchers at Walailak University, Prince of Songkla University and the University of Alberta, has the potential to offer a user-friendly, non-invasive method for prolonged delivery of active ingredients to the skin.
A natural alternative to steroids and antibiotics?
The study set out to develop an alternative to current topical treatments for inflammatory skin conditions. Existing options, such as corticosteroids and antibiotics, can lead to adverse effects such as skin thinning, dryness, redness, and irritation.
In traditional Thai medicine, CA rhizomes have a long history of use for treating skin disorders, wounds, and inflammation.
The researchers’ intention was to fill a knowledge gap and find applications that have good anti-inflammatory and antibacterial properties but that come with fewer side effects.
The key active compound in the Curcuma genus is curcumin, which is already known for its anti-inflammatory, antioxidant and anti-acne effects.
However, curcumin is known to be unstable, degrading rapidly when exposed to high temperatures, alkaline pH or UV light. The researchers overcame this challenge by incorporating the extract into a stable hydrogel patch.
Controlled release delivery system enhances efficacy
The researchers formulated several hydrogel patches using biodegradable polymers, including carrageenan, locust bean gum (LG), and Polyvinylpyrrolidone K30 (PVP-K30). The best-performing formulation, named CA2, used an optimal 1:1 ratio of carrageenan to LG.
The CA2 patch displayed excellent physical and mechanical properties — it was smooth, durable and flexible, making it ideal for use as a face mask or targeted patch.
Crucially, the patch successfully encapsulated the C. aromatica extract. It showed the highest percentage of curcumin loaded, which confirmed that the extract was fully loaded and compatible with the hydrogel matrix, forming a smooth, uniform surface that was both suitable and visually appealing for use.
The study highlighted the patch’s ability to deliver the active ingredient over an extended period. Curcumin was released rapidly within the first 30 minutes, which is beneficial for immediate topical relief. The release was also sustained, reaching its maximum rate at 12 hours and showing permeation into the skin that lasted for 24 hours.
The prolonged release of curcumin was advantageous for a prolonged duration of action. The release kinetics of the patch, which better fit Higuchi’s model, confirmed this sustained action.
Potent dual action
The CA2 hydrogel patch was put through rigorous in vitro testing to confirm its biological activity against the two primary factors of acne and inflammatory skin diseases — inflammation and the Cutibacterium acnes (C. acnes) bacteria.
Firstly, the researchers tested the patch’s anti-inflammatory activity by observing its ability to inhibit nitric oxide (NO) production in immune cells. The CA2 hydrogel patch demonstrated strong inhibitory activity, with an IC50 value of 19.85 ± 0.82μg/mL.
The anti-inflammatory activity of the CA2 hydrogel patch was similar to that of the C. aromatica extract itself, which indicated that the hydrogel base neither interfered with nor diminished the bioactivity of the extract.
Furthermore, the patch showed no toxicity to cells. This was unlike the curcumin standard, which showed toxicity at higher concentrations.
Secondly, the patch was tested for its anti-acne activity against C. acnes using a disc diffusion method. The CA2 patch showed a strong effect, creating an inhibition zone of 12.70 ± 2.10mm against the bacteria.
The results showed that adding C. aromatica ethanolic extract at a concentration of 1% to the hydrogel patch was sufficient for inhibiting C. acnes.
Importantly, the CA2 patch outperformed two commercial anti-acne patches — one containing 0.4% salicylic acid, and an acne-absorbing patch —both of which showed no inhibition against C. acnes in this study.
Potential for new products
The study confirmed that the CA2 hydrogel patch not only boasted strong anti-inflammatory and anti-acne activities, but also exhibited suitable physicochemical properties, including an acidic pH (5.57 to 5.58), which is beneficial for maintaining the skin’s natural protective barrier and preventing irritation.
Microscopic analysis using Scanning Electron Microscopy (SEM) showed that the C. aromatica extract was completely dispersed and evenly distributed within the hydrogel matrix, confirming its stability and uniformity.
While the in vitro results were highly promising, the research team also emphasised the need for further studies on product stability, as well as in vivo evaluation and clinical investigations.
The researchers wrote: “This study supports the traditional dermatological use of CA, and indicates that the CA2 hydrogel patch showed strong cosmetic potential for anti-inflammatory and anti-acne skin care applications.
“Furthermore, based on its bioactive response, the CA2 hydrogel patch may serve as a preliminary platform for future therapeutic development in dermatology, pending further studies on product stability, in vivo evaluation, and clinical investigations to confirm its safety and efficacy.”
Source: Cosmetics
“A Novel Development of a Curcuma aromatica Salisb Extract-Loaded Hydrogel Patch for Acne and Skin Inflammation: Physicochemical Properties and In Vitro Anti-Inflammatory and Anti-Acne Activities”
https://doi.org/10.3390/cosmetics12060240
Authors: Chonthicha Kongkwamcharoen, et al.
