The aim of this study was to obtain new vehicles for topical formulations based on the mixture of hydrogels (aqueous systems) with oleogels (lipophilic systems). Several formulations were prepared using different oleogels mixed with polyacrylic acid hydrogel without addition of other ingredients. The moisturizing effect of the bigels was assessed along with the hydrogel and oleogels used in their preparation by carrying out an in vivo study with 14 healthy volunteers. Corneometer measurements were taken each hour during a five-hour period after product's application. Stability tests (storage at 20 and 40 degrees C for six months) and mechanical characterization were also carried out. Stability tests showed no modifications of the textural properties and appearance over a six-month period at 20 degrees C. At accelerated conditions, modifications of colour and textural properties were detected after six months' storage. While retaining the mechanical and sensory properties of the hydrogel, the bigels showed simultaneously an enhanced moisturizing effect, making them promising candidates for topical formulations.
