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Vitamin D is an essential nutrient with important immunomodulatory properties. As a fat-soluble compound, Vitamin D (and its D3 form) is immiscible with water, which presents challenges to absorption. In an in vitro setting, the current study characterizes novel micellar formulations of Vitamin D3 designed to improve absorption. Techniques used to evaluate and compare the micellar formulations against a non-micellar formula include the following: cryo-SEM to determine morphology; laser diffraction to determine particle size and distribution; zeta potential to determine stability of the particles; solubility assays to determine solubility in water and gastrointestinal media; and Caco-2 cell monolayers to determine intestinal permeability. Results show advantageous features (particle size range in the low micrometres with an average zeta potential of −51.56 ± 2.76 mV), as well as significant improvements in intestinal permeability, in one optimized micellar formula (LipoMicel®). When introduced to Caco-2 cells, LipoMicel’s permeability was significantly better than the control (p < 0.01; ANOVA). Findings of this study suggest that the novel micellar form of Vitamin D3 (LipoMicel) has the potential to promote absorption of Vitamin D3. Thus, it can serve as a promising candidate for follow-up in vivo studies in humans.

Background: Quercetin, a flavonoid found in plant-based foods, has a range of biological activities that may be beneficial for human health. The pharmacokinetic profile of quercetin remains, however, a limiting factor for its use as a nutritional supplement. Quercetin LipoMicel®—a novel delivery system encapsulating quercetin into a liquid micelle matrix—has been designed to address the low bioavailability issue associated with non-conjugated forms by improving the absorption of quercetin. Objective: The purpose of this study was to evaluate the solubility and gastrointestinal absorption of quercetin in a novel Quercetin LipoMicel delivery system in healthy adult volunteers by comparing it with free quercetin and another commercial quercetin product. Several pharmacokinetic parameters were compared between these three formulations. Methods: Twelve healthy adult male and female volunteers aged between 21 and 65, with BMIs under 30, participated in a non-blinded, crossover bioavailability study conducted with three quercetin products. Each treatment contained a total dose of 500 mg quercetin. Capillary whole blood samples from participants were collected serially at intervals from 0–24 hours. Quercetin concentrations were detected and measured by ultra-performance liquid chromatography (UHPLC) coupled to a Thermo QExactive Orbitrap Mass Spectrometer. Solubility of quercetin in water and simulated gastrointestinal media was determined by UHPLC. Results: Oral absorption of quercetin was significantly enhanced with the LipoMicel delivery system compared to free quercetin. Improvements in in vitro gastric stability and intestinal solubility were observed with LipoMicel, leading to significantly higher blood concentration and enhanced duration of a stable concentration of quercetin in the body. Compared to free quercetin, 8- and 9-fold increases in AUC and Cmax were attained with the LipoMicel delivery system, and 10-fold higher quercetin plasma concentrations detected at 12 hours after administration. Conclusions: Quercetin LipoMicel represents an efficient delivery system for augmenting the bioavailability of quercetin in vivo. Significantly higher blood concentrations and a sustained release of quercetin over the study period was achieved following the administration of quercetin via the LipoMicel technology. Optimization in the in vivo bioavailability of quercetin may promote its salutary effects.