Review of Applications and Future Prospects of Stimuli-Responsive Hydrogel Based on Thermo-Responsive Biopolymers in Drug Delivery Systems.

Some of thermo-responsive polysaccharides, namely, cellulose, xyloglucan, and chitosan, and protein-like gelatin or elastin-like polypeptides can exhibit temperature dependent sol-gel transitions. Due to their biodegradability, biocompatibility, and non-toxicity, such biomaterials are becoming popular for drug delivery and tissue engineering applications. This paper aims to review the properties of sol-gel transition, mechanical strength, drug release (bioavailability of drugs), and cytotoxicity of stimuli-responsive hydrogel made of thermo-responsive biopolymers in drug delivery systems.

Influence of pH-responsive compounds synthesized from chitosan and hyaluronic acid on dual-responsive (pH/temperature) hydrogel drug delivery systems of Cortex Moutan.

The polysaccharide-based pH-responsive compounds, namely, N,N,N-trimethyl chitosan (TMC), polyethylene glycolated hyaluronic acid (PEG-HA), and polysaccharide-based nano-conjugate of hyaluronic acid, chitosan oligosaccharide and alanine [HA-Ala-Chito(oligo)] were chemically synthesized using biopolymers chitosan and hyaluronic acid, and applied here to observe the changes in morphology, pH-stability, mechanical and drug-release behavior, and cytotoxicity of thermo-responsive polymer: Poloxamer 407 (PF127)-based drug delivery systems for traditional Chinese medicine Cortex Moutan (CM). The thermo-responsive hydrogel of PF127 loaded with CM (Gel) was used as control. The dual-responsive (pH/temperature) hydrogels: PF127/TMC/PEG-HA (Gel) and PF127/HA-Ala-Chito(oligo) (Gel) showed improved mechanical behavior as obtained by rheology and mechanical agitation study, and pH-stability under various external pH conditions, and those improvements occurred due to the addition of polysaccharide-based pH-responsive compounds in the systems.

Drug delivery system of dual-responsive PF127 hydrogel with polysaccharide-based nano-conjugate for textile-based transdermal therapy.

Pluronic F-127 based dual-responsive (pH/temperature) hydrogel drug delivery system was developed involving polysaccharide-based nano-conjugate of hyaluronic acid and chitosan oligosaccharide lactate and applied for loading of gallic acid which is the principal component of traditional Chinese medicine Cortex Moutan recommended in the treatment of atopic dermatitis. The polysaccharide-based nano-conjugate was used as pH-responsive compound in the formulation and its amphiphilic character was determined colorimetrically. Microstructure analysis by SEM and TEM indicated highly porous hydrogel network and well-dispersed micellar structures, respectively, after modification with the nano-conjugate, and so, release property of the hydrogel for drug was significantly improved.

Dual-responsive (pH/temperature) Pluronic F-127 hydrogel drug delivery system for textile-based transdermal therapy.

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 (H-NMR and FTIR), and added to the formulations to enhance drug release from the hydrogels, and increase the drug targeting of the carriers.

Thermoresponsive Hydrogels and Their Biomedical Applications: Special Insight into Their Applications in Textile Based Transdermal Therapy.

Various natural and synthetic polymers are capable of showing thermoresponsive properties and their hydrogels are finding a wide range of biomedical applications including drug delivery, tissue engineering and wound healing. Thermoresponsive hydrogels use temperature as external stimulus to show sol-gel transition and most of the thermoresponsive polymers can form hydrogels around body temperature. The availability of natural thermoresponsive polymers and multiple preparation methods of synthetic polymers, simple preparation method and high functionality of thermoresponsive hydrogels offer many advantages for developing drug delivery systems based on thermoresponsive hydrogels.

Enhanced Transdermal Permeability via Constructing the Porous Structure of Poloxamer-Based Hydrogel.

A major concern for transdermal drug delivery systems is the low bioavailability of targeted drugs primarily caused by the skin's barrier function. The resistance to the carrier matrix for the diffusion and transport of drugs, however, is routinely ignored. This study reports a promising and attractive approach to reducing the resistance to drug transport in the carrier matrix, to enhance drug permeability and bioavailability via enhanced concentration-gradient of the driving force for transdermal purposes.

Dual-functional transdermal drug delivery system with controllable drug loading based on thermosensitive poloxamer hydrogel for atopic dermatitis treatment.

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.

Gallic Acid Is the Major Active Component of Cortex Moutan in Inhibiting Immune Maturation of Human Monocyte-Derived Dendritic Cells.

Atopic dermatitis (AD) is a widely prevalent and chronically relapsing inflammatory skin disease. Penta Herbs Formula (PHF) is efficacious in improving the quality of life and reducing topical corticosteroid used in children with AD and one of the active herbs it contains is Cortex Moutan. Recent studies showed that altered functions of dendritic cells (DC) were observed in atopic individuals, suggesting that DC might play a major role in the generation and maintenance of inflammation by their production of pro-inflammatory cytokines.

Microencapsulation of Traditional Chinese Herbs-PentaHerbs extracts and potential application in healthcare textiles.

In this work, Traditional Chinese Herbs (TCH)-PentaHerbs--was successfully microencapsulated in chitosan-sodium alginate (CSA) blend matrix using emulsion-chemical cross-linking method and the final product was characterised with regard to structure, surface morphology, particle size, in vitro drug release and skin toxicity by means of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), laser diffraction particle size analysis, high performance liquid chromatography (HPLC) and methyl thiazolyl tetrazolium (MTT) and lactate dehydrogenase (LDH) release assays respectively. Results showed that the microcapsules were in spherical form with diameter mostly in the range of 3-18 μm and that the release performance of the microcapsules was influenced by pH value of phosphate buffer solution (PBS). The microcapsules had no toxic effects on cells and were successfully grafted onto the surface of cotton fabrics.

Anti-allergic drug discovery in China for eczema: current methods and future strategies.

Introduction: Eczema is a common childhood atopic disease associated with chronicity and impaired quality of life. As there is no cure for this disease, treatment relies on topical and systemic anti-allergic or immunomodulating therapies. Topical corticosteroids, macrolide immunosuppressants and oral immunomodulating drugs have been the mainstay for the treatment of recalcitrant disease.

Anti-inflammatory and anti-allergic activities of Pentaherb formula, Moutan Cortex (Danpi) and gallic acid.

Pentaherb formula (PHF) has been proven to improve the quality of life of children with atopic dermatitis without side effects. The aim of this study was to elucidate the potential anti-inflammatory and anti-allergic activities of PHF, Moutan Cortex (Danpi/DP) and gallic acid (GA) using human basophils (KU812 cells), which are crucial effector cells in allergic inflammation. PHF, DP and GA could significantly suppress the expression of allergic inflammatory cytokine IL-33-upregulated intercellular adhesion molecule (ICAM)-1, and the release of chemokines CCL2, CCL5, CXCL8 and inflammatory cytokine IL-6 from KU812 cells (all p < 0.

Preparation and characterisation of chitosan microcapsules loaded with Cortex Moutan.

The process of preparation and characterisation of chitosan microcapsules loaded with Cortex Moutan was studied and the optimum condition for microcapsule preparation was investigated by orthogonal array analysis. Based on the yield percentage of microcapsule, the optimum condition for microcapsule preparation was (i) core-shell ratio=1:2; (ii) chitosan concentration=6% (w/v); (iii) agitation speed=1100 rpm; and (iv) cross-linking time=90 min. Meanwhile, relative importance of the preparation parameters was in the order: core-shell ratio, agitation speed, chitosan concentration and cross-linking time.

Paraoxonase-1 deficiency in mice predisposes to vascular inflammation, oxidative stress, and thrombogenicity in the absence of hyperlipidemia.

Background: Paraoxonase-1 is a polymorphic enzyme that is strongly associated with circulating high-density lipoproteins. The absence of paraoxonase-1 in mice has been shown to promote diet-induced atherosclerosis. As paraoxonase-1 has been recently shown to be a lactonase, its functional role remains to be fully elucidated.