Improved Stability of Polyglycerol Polyricinoleate-Substituted Nanostructured Lipid Carrier Cholecalciferol Emulsions with Different Carrier Oils.

Cholecalciferol, also known as vitamin D , is a recognized therapeutic agent for treatment of bone diseases and cancer. However, instability and poor bioavailability have been major challenges for delivering Vitamin D . The objective of this study was to formulate improved nanostructured lipid carrier (NLC) vitamin D emulsions. We tested the effect of different carrier oils and the use of a solid lipid nanoparticle emulsifier, polyglycerol polyricinoleate (PGPR) on the stability of the vitamin D emulsions. In contrast to the control that used glyceryl monostearate (GMS) the PGPR substitution resulted in relatively small particle sizes (0.30 to 0.43 μm), with high absolute value of zeta potentials (39.5 to 67.8 mV) and high encapsulation efficiency (85.2% to 90.4%). The stability of the NLC emulsions against environmental stresses was evaluated under varying conditions of ionic strength, pH, freeze-thaw cycles, and storage at different temperatures. Although NLC emulsions were stable at high ionic strengths, they were found to be unstable at low pH (<3), which led to aggregation and coalescence of emulsion droplets. In case of freeze-thaw stress, although relatively stable compared to control NLC, the PGPR substituted groups exhibited a slight increase in particle size and a decrease in zeta potential when the cycle was repeated five times. Additionally, we found that PGPR-substituted emulsions showed higher liquid dispersion stability than controls at 25 and 65 °C. Thus, we have formulated a modified NLC vitamin D emulsion that can be widely used in the food industry. PRACTICAL APPLICATION: Vitamin D , an essential micronutrient, is often added as supplements in food products and beverages for added health benefits. However, the stability of vitamin D emulsions that are used in the preparation of such products has been a major concern. We have developed a modified emulsion that has improved stability against environmental stresses. We believe, in future, this formulation can be efficiently used in the food industry.