Preparation of vitamin D3-loaded oil-in-water-in-oil double emulsions using psyllium gum: optimization using response surface methodology

Abstract

In this study, the encapsulation of vitamin D3 into a double emulsion with psyllium gum in the aqueous phase and lecithin in the oil phase was optimized and modeled. The optimal values of the three independent variables were generated using a faced-centered central composite design (FCCD). The Z-average (diameter of the emulsion droplets), polydispersity index (PDI), zeta potential, interfacial tension, creaming index, and encapsulation efficiency are among the quality evaluation metrics. According to the findings, the Z-average in the double emulsion was inversely affected by the psyllium gum concentration. The findings indicated that time after production had a significant direct influence on the Z-average. All freshly manufactured formulations may be characterized as good stable emulsions, according to the measurement of double emulsions’ zeta potential after preparation (negative charge lower than − 40.1 mV). During storage, the zeta potential value exhibited an upward trend. The creaming index was influenced significantly by storage time (p < 0.05) and at the end of storage time, the creaming index was 19.2% (in the sample with no gum and containing 0.25% lecithin). Analysis revealed that the interfacial tension was reduced as a result of the inclusion of the psyllium gum. On the other hand, prolonging storage lengthened the interfacial tension's magnitude. According to the findings, gum content and time had a significant impact on the encapsulation efficiency of primary and double emulsions. Finally, the optimal double emulsion preparation parameters based on maximum encapsulation efficiency were 1% psyllium gum, 1.125% lecithin, and a storage time equal to 25 days at 8 °C, with an obtained encapsulation efficiency of the double emulsion of 93.26%.