A dual-responsive hydrogel (pH/temperature) was developed from a thermos-responsive polymer, pluronic F-127 (PF127), and pH-responsive polymers, N,N,N-trimethyl chitosan (TMC) and polyethylene glycolated hyaluronic acid (PEG-HA). Gallic acid, the principal component of the traditional Chinese drug Cortex Moutan was loaded into the hydrogel (PF127/TMC/PEG-HA) for possible application in textile-based transdermal therapy as Cortex Moutan has been proven to be an effective drug for the treatment of atopic dermatitis (AD). TMC and PEG-HA were synthesized, characterized (¹H-NMR and FTIR), and added to the formulations to enhance drug release from the hydrogels, and increase the drug targeting of the carriers. The thermo-responsive properties of the hydrogel were assessed by dynamic viscosity analysis and the tube inversion method, and the pH-responsiveness of the formulation was determined by changing the pH of the external media. Rheology study of the hydrogels showed that complex viscosity and storage/loss moduli for PF127/TMC/PEG-HA hydrogel formulation are higher than PF127 hydrogel. The microstructure analysis by reflection SAXS indicated similar type of frozen inhomogeneity of hydrogel formulations. Various characterizations such as FTIR, SEM, TEM, zeta potential, and degradation of the hydrogel formulation indicated that the PF127/TMC/PEG-HA hydrogel showed better physico-chemical properties and morphology than did the PF127 hydrogel, and drug release was also higher for the PF127/TMC/PEG-HA hydrogel than for PF127. The drug release from hydrogels followed more closely first-order rate model than other rate models.

The treatment of atopic dermatitis (AD) has long been viewed as a problematic issue by the medical profession. Although a wide variety of complementary therapies have been introduced, they fail to combine the skin moisturizing and drug supply for AD patients. This study reports the development of a thermo-sensitive Poloxamer 407/Carboxymethyl cellulose sodium (P407/CMCs) composite hydrogel formulation with twin functions of moisture and drug supply for AD treatment. It was found that the presence of CMCs can appreciably improve the physical properties of P407 hydrogel, which makes it more suitable for tailored drug loading. The fabricated P407/CMCs composite hydrogel was also characterized in terms of surface morphology by field emission scanning electron microscopy (FE-SEM), rheological properties by a rheometer, release profilein vitroby dialysis method and cytotoxicity test. More importantly, the findings from transdermal drug delivery behavior revealed that P407/CMCs showed desirable percutaneous performance. Additionally, analysis of cytotoxicity test suggested that P407/CMCs composite hydrogel is a high-security therapy for clinical trials and thus exhibits a promising way to treat AD with skin moisturizing and medication.