Sistema microemulsionado contendo pentoxifilina para tratamento de afecções dermatológicas

Abstract

Some inflammatory skin diseases are treated with drugs carried on conventional dosage forms that often fail to achieve adequate concentrations in the tissue to generate maximum pharmacological effect. Pentoxifylline (PTX) is one of these drugs widely studied due to its anti-inflammatory activity by inhibiting the production of TNFα

and other proinflammatory cytokines. The use of PTX incorporated into microemulsions (ME) would be a novel alternative for the treatment of inflammatory skin disorders. This new drug delivery system can be used topically and can be able to increase the permeation through skin and the effectiveness of several drugs compared to conventional treatments. The aim of this work was to develop a microemulsion containing PTX (PTX-ME) for topical use. The formulation obtained from the pseudoternary phase diagrams was characterized and evaluated using methods such as polarized light microscopy (MLP), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The in vitro release profile was determined using the model of Franz cells and antiedematogenic activity in vivo was determined using the technique of paw edema induced by carrageenan. The ME was composed of distilled water (5%), acid–capric/caprylic triglycerides (51%), Tween 80 (39.6%) and Brij TM 52 (4.4%). Analyzes of MLP, DSC, and TEM were able to confirm that the ME obtained was water-in-oil (W/O) type. The formulation was thermodynamically stable against thermic stress. Beside this, it had physicalchemical characteristics that allow its topical use. In vitro release of PTX-ME followed

the Higuchi kinetic model. Additionally, it showed significant anti-inflammatory activity

in

paw edema induced by carrageenan in all stages of the assay. Consequently, the PTX-ME showed an interesting alternative for treatment of dermatological disorders.