The effect of adding GA to 1 % (w/v) TSX on the phase transitions was detected by tube inversion and optical changes. The size of the aggregated domains and the morphology of the GA/TSX blends in the gel states were investigated using SAXS and an optical microscope, respectively, at 25 A degrees C. Turbidity and tube inversion determinations showed that 1TSX, 0.2GA/1TSX and 0.4GA/1TSX could not form a gel but the blends of 0.6GA/1TSX, 0.8GA/1TSX and 1GA/1TSX formed turbid gels and exhibited a thermoreversible phase transformation. Upon heating, the gel-to-sol temperatures were between 42 and 52 A degrees C and increased with an increase of the GA concentration. Upon cooling, the sol-to-gel temperatures were between 26 and 36 A degrees C with the lower temperatures for the lower concentrations of GA in the blends. According to SAXS analyses, molecular aggregation appeared in the blends that exhibited the gelling ability with an aggregation domain of 2.2-2.9 nm. The size of the aggregation domain increased as the GA concentration increased. Fibrillation was observed for the gels of 0.6GA/1TSX, 0.8GA/1TSX and 1GA/1TSX from the optical micrographs. Furthermore, the blends of GA/TSX caused synergistic antioxidant activity as determined by a reduction of the DPPH radicals. In addition, these GA/TSX gels exhibited a sustained release of GA by a non-Fickian mechanism. These gels may have a potential use for the topical delivery of GA.