Organogel composed of poloxamer 188 and passion fruit oil: Sol-gel transition, rheology, and mechanical properties

Abstract

The present work at hands deals with physicochemical properties of an organogel composed of non-ionic triblock copolymer poloxamer 188 and passion fruit oil. To provide the characterization it was investigated the rheological (continuous shear and oscillatory) properties, sol-gel transition temperature, mechanical properties (hardness, compressibility, adhesiveness, cohesiveness and elasticity) and softness index. Moreover, we investigated the possible correlation between the rheological and mechanical characteristics to study the structuring of formulations and to select the best organogel for pharmaceutical applications. Mechanical and rheological characteristics showed to be temperature, polymer and oil concentration dependent. The increase of poloxamer 188 and passion fruit oil amounts in formulations displayed more expressive textural properties and softness. The organogels exhibited plastic flow with higher yield value, consistency index and thixotropic behavior at higher poloxamer 188 concentrations. All formulations showed viscoelastic properties and the sol-gel transition temperature was dependent of polymer and oil concentration in formulations. Rheological-mechanical correlation coefficient evidenced that rheological methods were more sensible than the mechanical ones. Considering the mechanical and rheological characteristics, the organogel composed of poloxamer 188 (35%, w/w) and passion fruit oil (16.7%, w/w) can be considered potentially promising as a drug delivery platform for pharmaceutical applications.