Development and Characterization of a Hydrogel Containing Silver Sulfadiazine for Antimicrobial Topical Applications. Part II: Stability, Cytotoxicity and Silver Release Patterns

Abstract Hydrogels are interesting for use in the treatment of topical wounds due to their virtually zero toxicity, and capacity for extended release of pharmaceuticals. Silver sulfadiazine (SSDZ) is the drug of choice in the treatment of skin burns. The aim of the study was to determine cytotoxicity, antimicrobial activity and stability of a PVA hydrogel with integrated silver sulfadiazine. SSDZ-hydrogels were prepared using 10% (w/w) PVA (either 89% or 99% hydrolyzed) and 1% (w/w) silver sulfadiazine. Cellular viability was assessed via MTS assays, antimicrobial activity via disk-diffusion and accelerated stability tests were carried out with analysis at 0, 30, 60, 90 and 180 days of storage at 40 ± 2 °C and a relative humidity of 75 ± 5%. The parameters evaluated included organoleptic characteristics, moisture, swelling ability, mechanical strength, FTIR, XRD, TGA and DSC, and silver release patterns via XRD and potentiometry. Cell viability tests indicated some cytotoxicity, although within acceptable levels. After 90 days of storage, SSDZ hydrogel samples exhibited a brown coloration, probably due to the formation of Ag or Ag2O nanoparticles. The SSDZ-loaded hydrogels suffered visual and physical changes; however, these changes did not compromise its use as occlusive wound dressings or its antimicrobial properties.

Biomaterials Based on Essential Fatty Acids and Carbohydrates for Chronic Wounds.

Chronic wounds such as decubitus ulcer remain challenging due to their integrated and overlapping phases. The matrix metalloproteinases (MMPs) enzymes, whose main function is to degrade all kinds of extracellular matrix (ECM) proteins, aid cellular migration and extracellular remodeling. MMPs, in the wound bed, allow the lysis of the dead tissues, by which the macrophages task becomes easier to digest the dead cells. MMPs activities should be monitored and inhibited as the healing process proceeds. If MMPs are not inhibited in time, they will break down tissue to attack the ECM itself creating chronic wounds. In the current work, conjugated linoleic acid (CLA) and ricinoleic acid (RA) are extracted from commercial oils as MMPs inhibitors. A pharmaceutical carrier is formulated containing chitosan fine particles, impregnated silver nanoparticles into microcrystalline cellulose, CLA and RA. Carrier and the active ingredients were prepared and characterized by spectral and morphological analysis. The final formulation was examined for antimicrobial, cytotoxicity, and in-vivo wound healing activity. Results showed a strong inhibitory activity against the tested pathogenic microorganisms for the silver contacting samples. The rates of wound closures during wound healing in diabetic male-rats of formulas containing ricinoleic acid was faster than that containing conjugated linoleic acid.

Iontophoresis: principles and applications / Iontoforese: princípios e aplicações

Introduction Iontophoresis is a noninvasive technique used to increase transdermal penetration of substances through the skin layer (epidermis, dermis and hypodermis) in a controlled manner. Technological advance in recent decades have provided reduced cost of equipment needed for implementation, which allowed for the expansion of this technique. Objective The aim of this paper is to present the state of the art on iontophoresis, ranging from the atomic characteristics of the ion formation to the current applications of the technique. Methods Were researched papers from databases: IOP publishing, ScienceDirect, Pubmed, Springer, IEEE Xplore, Google Scholar and books with keywords iontophoresis, ions, topical applications between 1967 and 2010. Results Were selected (number of papers and database) 1 IOP Publishing, 1 from ScienceDirect, Central, 1 from Springer, 2 from PubMed, 11 from IEEE Xplore, 35 from Google Scholar, and 15 books, totaling 66 references and websites with nationally marketed electrotherapy products. Conclusion Iontophoresis is suitable for applications such as acetic acid (calcific tendinitis and myositis ossificans), calcium chloride and magnesium sulfate (control of musculoskeletal spasms), dexamethasone (inflammation), lidocaine (inflammation of soft tissues), zinc oxide (rheumatoid arthritis). It is also used in cosmetic applications with devices attached to the skin and for eye treatment aimed at specific tissues of the eye, providing a treatment option for various eye diseases, reducing the complications secondary to traditional methods of treatment. The advantages are the significant increase in the release and control of therapeutic agents, including drugs with high molecular weight. The disadvantages of iontophoresis are the complexity of the drug release system and prolonged exposure of the skin to an electrical current. .

Introdução A iontoforese é uma técnica não invasiva utilizada para aumentar, de forma controlada, a penetração transdermal de substâncias através das camadas da pele (epiderme, derme e hipoderme). O avanço tecnológico nas últimas décadas proporcionou uma redução no custo dos equipamentos necessários à sua aplicação, o que possibilitou a expansão dessa técnica. Objetivo Apresentar o estado da arte sobre iontoforese, abrangendo desde as características atômicas da formação do íon até as atuais aplicações da técnica. Métodos Foram pesquisados artigos das bases de pesquisa: IOP publishing, ScienceDirect, Pubmed, Springer, IEEE Xplore, Google Scholar e livros com os unitermos: iontophoresis, ions, topical applications entre os anos de 1967 e 2010. Resultados Foram selecionados (número de artigos e base de pesquisa) 1 da IOP Publishing, 1 da ScienceDirect, 1 da Springer, 2 da PubMed, 11 da IEEE Xplore, 35 do Google Scholar e 15 livros, totalizando 66 referências, além de websites com produtos comerciais nacionais de eletroterapia. Conclusão A iontoforese é indicada para aplicações como de ácido acético (tendinite calcificante e miosite ossificante), cloreto de cálcio e sulfato de magnésio (controle de espasmos musculoesqueléticos), dexametasona (inflamação), lidocaína (inflamação de tecidos moles), óxido de zinco (artrite reumatóide). Também é utilizada em aplicações cosméticas com dispositivos aderidos à pele e em tratamento ocular visando tecidos específicos do olho, oferecendo uma forma de tratamento para diversas doenças oculares, diminuindo as complicações apresentadas em métodos clássicos de tratamento. As vantagens ...