Vitamin D helps with intestinal absorption of calcium, promotes normal bone formation, and mineralisation. Deficiency in this nutrient could increase risks of cardiovascular disease, diabetes, inflammation, and rickets in children.
However, effective absorption of this lipid soluble vitamin in the body is proving to be a challenge. Vitamin D becomes unstable when exposed to air, water or heat. It has poor water solubility and oral bioavailability.
“Hence, encapsulation with a lipid delivery system is desirable to increase the stability, preserve the bioactivity, and enhance the absorption of this vitamin,” researchers from Korea’s Keimyung University and Kunsan National University, wrote.
The aim is to encapsulate the vitamin in a robust carrier that can withstand the gut’s digestive juices long enough to prevent the nutrient’s degradation before absorption in the body.
For the study, Vitamin D3 (VD3), the nutrient’s more potent version, was encapsulated in nanostructured lipid carriers (NLCs).
NLCs consist of solid lipid and liquid lipid at room temperature. The lipid droplets in NLCs are partially crystalised with an amorphous structure, so that nutrients can be stored in the core of the carrier. This means increased amounts of vitamin can be encapsulated, and its release in the body controlled.
NLCs tested in gastric environment
Vitamin D3-loaded NLCs (VD3-NLCs) were tested in simulated gastric fluid (SGF), followed by testing in simulated intestinal fluid (SIF). The VD3-NLCs in SGF were also incubated in a shaking water bath to simulate conditions in the stomach.
Meanwhile, dialysis sacks were used to evaluate the release of VD3 from the VD3-NLCs. The sacks were soaked in distilled water overnight before use, and then filled with VD3-NLCs and enzyme-free SGF and SIF. High-performance liquid chromatography (HPLC) analysis determined the amount of VD3 released after eight hours of digestion in SIF.
“The VD3-NLCs produced by 10 cycles of hot high pressure homogenization at 10,000 psi exhibited a small diameter (132.9 nm) with a low PDI (0.19), which are advantageous for absorption in the body,” researchers wrote.
“A high entrapment efficiency (85.6%) was attained and the NLCs remained stable during a 20-day evaluation period, which indicates that VD3 was successfully dispersed in the lipid matrix and no vitamin loss occurred during storage.”
The NLCs also protected the VD3 in simulated gastrointestinal conditions long enough to enable the release of 90 per cent of the nutrient in the body after eight hours of digestion in SIF.
“The feasibility of mass production, nontoxicity, and availability of excipients make NLCs industrially viable. Thus, NLCs can be considered as an advanced delivery system that can be valuable for encapsulating functional lipophilic compounds, such as fat-soluble vitamins,” concluded the study.
Source: Food Chemistry
DOI: 10.1016/j.foodchem.2017.01.015
“Development of nanostructured lipid carriers for the encapsulation and controlled release of vitamin D3”
Authors: Sung Jin Park, Coralia V Garcia, et al.