Physicochemical Characterization and Development of a Microemulsion System for Transdermal Use

A microemulsion (ME) carrier system containing diclofenac diethylamine (DDA) was developed and physicochemically characterized. In addition, a methodology for analytical determination of DDA by UV-Vis spectrophotometry was validated. The methodology used to produce the ME was simple and reliable, producing a stable ME system with a high DDA entrapment efficiency of 89.6 +/- 14.19%. The ME system presents a mean droplet size, conductivity, pH, refractive index and viscosity of around 50 nm, 300 mu S cm(-1), 7.0, 1.399, and 110 mPa, respectively. Furthermore, the analytical method developed to evaluate the DDA content was validated and used to quantify DDA in the ME formulations.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

MICROEMULSÃO: UM PROMISSOR CARREADOR PARA MOLÉCULAS INSOLÚVEIS

Microemulsão (ME) é um sistema que foi descoberto por Hoar e Schulman no ano de 1943 e que é termodinamicamente estável e isotropicamente translúcido de dois líquidos imiscíveis (óleo/água), estabilizados por um filme interfacial de tensoativos. O estudo de sistemas microemulsionados se baseia nas suas três teorias de formação: (1) teoria da solubilização, (2) teoria da tensão interfacial e (3) teoria termodinâmica. A estrutura formada é influenciada pelas propriedades físico-químicas dos componentes utilizados e da razão entre os componentes. O objetivo desta revisão foi avaliar o estado da arte de sistemas microemulsionados enfatizando uma abordagem teórica. Além disso, os recentes avanços sobre a aplicabilidade clínca e utilização como carreador de moléculas insolúveis foram discutidas. Palavras-chave: Aplicações Clínicas. Diagrama de Fases. Microemulsão. ABSTRACT Microemulsion: a promising carrier system for insoluble compounds Microemulsions (ME) are thermodynamically stable and isotropic systems of two immiscible liquids (oil/water), stabilized by an interfacial film of surfactants, discovered by Hoar and Schulman in 1943. The study of ME formation is based on three areas of theory: (1) solubilization, (2) interfacial tension and (3) thermodynamics. ME structures are influenced by the physicochemical properties and proportions of their ingredients. The goal of this review is to assess the state of the art of microemulsified systems, from a theoretical viewpoint. Also, recent progress on their clinical application and use as carriers for insoluble compounds is discussed. Keywords: Microemulsion. Pharmaceutical Application. Phase Diagram

Amphotericin B Microemulsion Reduces Toxicity and Maintains the Efficacy as an Antifungal Product

Amphotericin B remains the drug of choice for the treatment of most of the systemic fungal infections in immunodeficient patients. Because of the high incidence of adverse drug reactions the clinical use of Amphotericin B is rather limited. To reduce its toxicity new drug delivery systems has been suggested. Nevertheless, these carriers present several technological drawbacks that impair the development of a marketable product. The aim of this work was to develop an Amphotericin B microemulsion in order to increase its efficacy and decrease its toxicity compared to Fungizon (TM), the widely know inexpensive micellar system of Amphotericin B. Amphotericin B loaded microemulsion showed an average size close to 300 nm by photon correlation spectroscopy. In the UV spectrum, the observation of the monomeric peak at 405 nm, which was independent of the sample dilution, revealed that the Amphotericin B molecules were strongly and individually bound to the microemulsion droplets. The new microemulsion formulation had the same efficacy than Fungizon (TM) against C. albicans. Concerning toxicity, Amphotericin B loaded microemulsion showed lower toxicity against human red blood cells compared to the commercial product. Taken together, these results suggested that microemulsion is an eligible drug carrier for Amphotericin B or other water insoluble molecules, and it has potential applications to targeting fungal cells. Additionally, a novel formulation of Amphotericin B-loaded microemulsion was prepared by a straightforward and fast procedure.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq