Development of W₁/O/W₂ emulsion with gallic acid in the internal aqueous phase

The aim of this work is to develop a W₁/O/W₂ multiple emulsion with gallic acid in the internal aqueous phase (W₁). A quantification method for gallic acid using HPLC-UV was developed and validated. In the first step, a simple W₁/O emulsion was prepared with distilled water, polyglycerol polyricinoleate, sodium chloride, gallic acid and pH 5.0 sodium acetate buffer system. The second step consisted of adding the simple emulsion to the external aqueous phase (W₂) composed of distilled water, polysorbate 80 and xanthan gum. The multiple emulsion showed pseudoplastic behavior. After 28 days of analysis the multiple emulsion presented a stability index of 75% without pH variation, 89.61% of gallic acid concentration, 59.62% of antioxidant activity in the phosphomolybdenum complex assay and 80.58% of DPPH scavenging activity. It is concluded that the W₁/O/W₂ emulsion developed was stable for 28 days and maintained more than 50% of gallic acid antioxidant capacity.