Improved texture analysis for hydrogel characterization: Gel cohesiveness, adhesiveness, and hardness

The texture properties of formulation are an important parameter in optimization of topical formulations. These properties will affect applicability of the formulation at the administration site and therapy outcome. Our aim was to develop a fast and reliable method to characterize texture properties of hydrogels, namely cohesiveness, adhesiveness, and hardness. During the method development, we realized that the measurements setup needed to be adjusted for each hydrogel type, namely Carbopol, chitosan, and poloxamer hydrogels. The influence of the polymer concentration, pH, and incorporation of additives such as glycerol, drug solution, or liposomes on the texture properties, as determined by Texture Analyzer, was evaluated. In addition, the new method was applied to determine the changes during the accelerated stability testing. While Carbopol and poloxamer gels showed a linear relationship between the polymer concentration and texture properties, for low molecular weight chitosan gels the properties increased in exponential manner with increasing polymer concentration. The effect of incorporated liposomes on the gel properties was found to be dependent on the type of hydrogel. The hydrogel hardness was affected by the temperature as seen in accelerated stability testing. The method represents a valuable tool in pharmaceutical and cosmetics formulation development. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012