Development of textile-based therapy containing traditional Chinese medicine for atopic dermatitis treatment

Abstract

Atopic dermatitis (AD) is a common chronic inflammatory skin condition characterized by intense pruritus and a waxing and waning course in children. The prevalence of this condition has increased steadily worldwide over the past decades, with an estimated morbidity of 15% to 30% of affected adolescents, especially in the industrialized countries. AD imposes a great influence on the quality of life of children and their parents and causes significant social, economic and health care costs. The treatment of AD has long been a challenge for clinicians and practitioners for decades. Conventional mainstream medication always involves the use of topical or systemic corticosteroids, which may cause serious adverse effects such as striae, hypertension or even atrophy. Hence, the use of corticosteroids is highly not recommended, especially for young children with AD. A wide variety of complementary or alternative therapies, e.g., acupuncture, homeopathy, probiotics, autologous blood injection, massage therapy and herbal preparations, have therefore received considerable attention. In this thesis, a dual-functional textile-based Poloxamer 407/Carboxymethyl cellulose sodium (P407/CMCs) composite hydrogel transdermal therapy, i.e., moisture and drug supply, was developed for AD treatment. The fabricated P407/CMCs composite hydrogel was characterized by a series of analytical techniques. The presence of CMCs can appreciably improve the physical properties of P407 hydrogel, which makes it more suitable for tailored drug loading. The sol-gel transition temperature of P407/CMCs was accurately obtained via rheological analysis using a rheometer. FE-SEM images indicated that P407/CMCs composite hydrogel presented excellent porous structure. More importantly, the findings from transdermal drug delivery behavior revealed that P407/CMCs showed desirable percutaneous performance. The release kinetics and mechanism of model drug from P407/CMCs composite formulation were fully evaluated by the dialysis method. It was found that concentrations of P407 and CMCs showed significant influence on the release due to alteration of bulk viscosity of the system. An increase in pH values of release medium was found to appreciably impede the release of polar drug (CM) due to ionization. Elevated temperatures were also shown to facilitate the drug release. Moreover, the diffusional release behavior of CM from P407/CMCs composite hydrogel approximates to the first-order kinetic model. Additionally, porosity analysis showed that the porous structure of the P407 matrix was distinctly improved and optimized owing to the presence of CMCs. The pore size approximated to normal distribution and the fraction of pore number was increased by over tenfold. Transdermal studies showed that P407/CMCs saw a significant increase in drug permeability across the skin. This was not due to the permeation enhancing ability of CMCs, but enhanced concentration-gradient driving force caused by porous structure optimization. The diffusivity of drug within P407/CMCs hydrogel was thus enhanced owing to the presence of excellent porous structure. This suggests that P407/CMC with improved porous structure exhibited a feasible and promising way for the development of transdermal therapy with high permeability and bioavailability, thereby reducing or avoiding use of any chemical enhancers. The drug percutaneous penetration across the skin could be further enhanced by the addition of chemical enhancer (azone). This may provide an attractive alternative to achieve high drug permeability and bioavailability in transdermal application for the macromolecular drugs (e.g., vaccines and peptides), especially with the aid of suitable enhancers or penetration enhancing tools. More importantly, analysis of cytotoxicity test suggested that P407/CMCs composite hydrogel is safe for clinical trials. The preliminary clinical results showed that P407/CMCs hydrogel therapy was helpful in the quality of life of AD patients, with decreased use of topical corticosteroids. However, overall clinical evaluation indicated that the therapeutic effect was limited. This suggests that a more randomized, controlled clinical trial with a larger group of AD patients is required to more accurately evaluate the clinical therapeutic effect of P407/CMCs hydrogel therapy. Nevertheless, the pilot clinical trial provides a novel insight into the development of hydrogel-based transdermal therapy for AD treatment. Furthermore, the dyeing experiments showed that there was a great loss in the major active components of CM concoction despite of achieved hues in dyed fabrics, which suggests that the dyeing method was not suitable for the application of CM concoction in the development of healthcare textile for AD treatment.