In Vitro Antioxidant Activity of Chitosan Aqueous Solution: Effect of Salt Form

Purpose: To investigate the effect of salt form on the antioxidant activities of chitosan aqueous solution.Methods: The antioxidant activities of chitosan acetate (CS-acetate), chitosan hydroxybenzotriazole (CS-HOBt), chitosan thiamine pyrophosphate (CS-TPP) and chitosan ethylenediaminetetraacetic acid (CS-EDTA) solution were determined employing various established in vitro system such as superoxide and hydroxyl radicals scavenging, metal ion chelating and reducing power. Their chemical structures were characterized by nuclear magnetic resonance (NMR) and Fourier transform infraredspectrophotometry (FT-IR).Results: NMR and FT-IR show confirmed formation of chitosan salts. The 50 % inhibition concentration (IC50) of superoxide and hydroxyl radicals was 0.349 – 1.34 and 0.34 – 1.54 mg/mL, respectively. Among the salt forms, CS-acetate (IC50 = 0.349 mg/mL) showed the highest superoxide radical scavenging effect while CS-HOBt (IC50 = 0.34 mg/mL) showed the highest hydroxyl radical scavenging effect. With regard to metal ion chelating activity, CS-EDTA showed the highest chelating activity (approx 100 % at 1 mg/mL) while the others showed 20 % activity at a concentration of 1 mg/mL. The results for reducing power indicate that CS-TPP had the highest reducing power.Conclusion: The results indicate that antioxidant activity varied with the salt form. Thus, CS salts may be used as a source of antioxidants for pharmaceutical applications.Keywords: Chitosan, Antioxidant, Hydroxybenzotriazole, Thiamine pyrophosphate, Ethylenediaminetetraacetic aci

Gelatin porous scaffolds fabricated using a modified gas foaming technique: Characterisation and cytotoxicity assessment

The current study presents an effective and simple strategy to obtain stable porous scaffolds from gelatin via a gas foaming method. The technique exploits the intrinsic foaming ability of gelatin in the presence of CO2 to obtain a porous structure stabilised with glutaraldehyde. The produced scaffolds were characterised using physical and mechanical characterisation methods. The results showed that gas foaming may allow the tailoring of the 3-dimensional structure of the scaffolds with an interconnected porous structure. To assess the effectiveness of the preparation method in mitigating the potential cytotoxicity risk of using glutaraldehyde as a crosslinker, direct and in-direct cytotoxicity assays were performed at different concentrations of glutaraldehyde. The results indicate the potential of the gas foaming method, in the preparation of viable tissue engineering scaffolds

Advanced therapeutic dressings for effective wound healing

Advanced therapeutic dressings that take active part in wound healing to achieve rapid and complete healing of chronic wounds is of current research interest. There is a desire for novel strategies to achieve expeditious wound healing due to the enormous financial burden worldwide. This paper reviews the current state of wound healing and wound management products, with emphasis on the demand for more advanced forms of wound therapy and some of the current challenges and driving forces behind this demand. The paper reviews information mainly from peer reviewed literature and other publicly available sources such as the FDA. A major focus is the treatment of chronic wounds including amputations, diabetic and leg ulcers, pressure sores, surgical and traumatic wounds (e.g. accidents and burns) where patient immunity is low and the risk of infections and complications are high. The main dressings include medicated moist dressings, tissue engineered substitutes, biomaterials based biological dressings, biological and naturally derived dressings, medicated sutures and various combinations of the above classes. Finally, the review briefly discusses possible prospects of advanced wound healing including some of the emerging approaches such as hyperbaric oxygen, negative pressure wound therapy and laser wound healing, in routine clinical care

Development and Skin Penetration Pathway Evaluation Using Confocal Laser Scanning Microscopy of Microemulsions for Dermal Delivery Enhancement of Finasteride

This study aimed to develop microemulsions using poloxamer 124 as a surfactant to improve the skin penetration of finasteride and to investigate the skin penetration pathways of these microemulsions by colocalization techniques using confocal laser scanning microscopy (CLSM). The prepared finasteride-loaded microemulsions had average particle sizes ranging from 80.09 to 136.97 nm with particle size distributions within acceptable ranges and exhibited negative surface charges. The obtained microemulsions could significantly increase the skin penetration of finasteride compared to a finasteride solution. According to the skin penetration pathway evaluation conducted with CLSM, the microemulsions were hair follicle-targeted formulations due to penetration via the transfollicular pathway as a major skin penetration pathway. Additionally, this study found that the microemulsions also penetrated via the intercluster pathway more than via the intercellular pathway and transcellular pathway. The intercluster pathway, intercellular pathway, and transcellular pathway were considered only minor pathways

Tara tannin as active ingredient in electrospun fibrous delivery system

This study evaluated the releasing performance of tara tannin, a cocktail of plant polyphenols, incorporated in submicron fiber, produced by the electrospinning process. Polylactic acid was used as a polymer matrix that carried two loading levels of tara tannin, 14.3 and 22.3% dry weight in the final product. The fiber diameter of composite fibers was in the range 500–700 nm. The release of tara tannin was controlled by material attachment as there was no evidence of chemical bonding between materials. This was further confirmed by FTIR and DSC. From the five combinations of acid that were presented in tara tannin, galloylquinic acid, with the smallest molecular weight composition, was released in the largest proportion (%molar) and exhibited antioxidant activity. This was confirmed by 2,2-diphenyl-1-picrylhydrazyl assay and HPLC-MS analyses. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43646. (Résumé d'auteur