Novel Approach for the Approximation of Vitamin D3 Pharmacokinetics from In Vivo Absorption Studies

Liposomal encapsulation of cholecalciferol mitigates in vivo toxicity and delays tumor growth

Introduction

Vitamin D3 (cholecalciferol) has demonstrated potential anticancer properties, but its clinical application is limited by associated toxicity at effective doses. This study investigated the use of liposomal encapsulation to increase the therapeutic efficacy of vitamin D3 while mitigating its toxicity.

Methods

Liposomal vitamin D3 (VD-LP) was prepared via the film-hydration method and characterized for particle size, polydispersity index, encapsulation efficiency, and long-term stability. In vitro gene expression modulation was evaluated in monocytic THP-1 cells, and antiproliferative effects were assessed in HT29 (colorectal), BT474 (breast), and TRAMP-C1 (prostate) cancer cell lines. In vivo antitumor efficacy and toxicity were tested in a mouse model with subcutaneously implanted MC38 tumors. Tumor growth, survival rates, and serum calcium and phosphate levels were analyzed.

Results

VD-LP demonstrated high encapsulation efficiency and stability over 90 days, with a consistent particle size of approximately 83 nm. VD-LP modulated immune-related and metabolic gene expression in THP-1 cells, including upregulation of antimicrobial peptides and vitamin D receptor genes. VD-LP showed superior antiproliferative effects compared to free vitamin D3 in all tested cancer cell lines. In vivo, VD-LP delayed tumor growth and improved survival without causing hypercalcemia, highlighting its favorable toxicity profile.

Discussion

Liposomal encapsulation of vitamin D3 significantly improves its anticancer efficacy while mitigating toxicity, making it a promising strategy for future cancer therapies. VD-LP shows potential for enhanced therapeutic applications with reduced adverse effects, warranting further clinical exploration.

3D printed cacao-based formulations as nutrient carriers for immune system enhancement

This study explores the feasibility of using raw Greek honey-infused cacao-based formulations for three-dimensional printing (3DP). It evaluates their physicochemical properties, thermal stability, and rheological behaviour. Three honey varieties, one of which was Lavender Honey (LH), were incorporated into cacao printlets to assess their impact on structural integrity and compatibility with Vitamin D3 (VitD3), a bioactive compound known for immune system enhancement. Including honey aims to improve the nutritional profile, enhance the taste, and potentially increase the bioavailability of VitD3, which is limited by its hydrophobic nature and low oral absorption. Thermal analysis showed that honey-infused cacao printlets maintain a liquid-like state under ambient conditions and exhibit stability up to the printing temperature of 38 °C. Rheological assessments demonstrated that both individually and in combination, increased honey concentrations and VitD3 incorporation enhance viscosity. These changes improve printability and structural integrity during 3DP. While raw LH demonstrated antibacterial activity, no antibacterial efficacy was observed in the LH-based printlets after incubation. LH at a 10% concentration emerged as the optimal formulation, demonstrating balanced structural properties and effective miscibility with VitD3. This study highlights how raw Greek honey produced without chemical miticides, has the potential to enhance the functionality and palatability of 3D-printed health supplements. It utilises honey's antimicrobial properties and taste benefits while promoting immune system support through VitD3 integration. The findings highlight the versatility of honey-infused cacao printlets in developing personalized health supplements and pharmaceuticals, suggesting their promising role as delivery systems in personalized medicine. Honeys widely accepted sensory qualities and its application in food products are the basis for the proposition that it enhances palatability. These attributes imply that honey could positively influence the acceptability of the product.

Effect of Consuming Salmon Products on Vitamin D Status of Young Caucasian Women in Autumn-A Randomized 8-Week Dietary VISA 2 (Vitamin D in Salmon Part 2) Intervention Study

BACKGROUND/OBJECTIVES

Young women are often at risk of vitamin D deficiency, while fatty fish can provide significant amounts of it, which is especially important when no vitamin D skin synthesis is possible due to limited sunshine exposure. This study aimed to analyze the impact of increasing the intake of salmon in various forms (smoked salmon, salmon sausages) on vitamin D status of young women in autumn.

METHODS

The 8-week intervention involved 120 non-obese women, aged 20-25 years. Participants were randomly assigned to one of three groups: smoked salmon (25 g/day), salmon sausage (100 g/day), or a control group. Both intervention products provided approximately 5 µg of vitamin D daily. Serum concentrations of 25(OH)D as well as vitamin D intakes were assessed pre-, mid-, and post-intervention.

RESULTS

The median vitamin D intake at baseline was 2.7-3.4 µg/day and did not differ between the groups (p > 0.05), while during the intervention, it was highest in the smoked salmon group (p < 0.001) and amounted to 7.3 µg/day. While all groups experienced a decrease in 25(OH)D serum concentrations, the decrease was significantly smaller in the salmon sausage group compared to the control group (-4.3 vs. -15.0 nmol/L, p < 0.05), and no significant difference was observed between the smoked salmon and control group after 8 weeks (p > 0.05). Moreover, in the salmon sausage group, the intervention was more effective among participants with an inadequate vitamin D status at baseline (25(OH)D change after the intervention: -3.0 vs. -5.4 nmol/L, p < 0.05; inadequate vs. adequate baseline vitamin D status).

CONCLUSIONS

Increasing the intake of salmon, and hence of vitamin D, was not enough to maintain the vitamin D status of young women in autumn. It seems that other, not-yet-fully-understood factors, may influence vitamin D absorption and/or metabolism, thereby affecting the outcomes of such interventions indicating that further research is needed. Nevertheless, it may be concluded that increasing salmon sausage intake might aid slow down the natural decline of 25(OH)D in young women in autumn.

Recent Advances in the Use of Vitamin D Organic Nanocarriers for Drug Delivery

Nanotechnology, now established as a transformative technology, has revolutionized medicine by enabling highly targeted drug delivery. The use of organic nanocarriers in drug delivery systems significantly enhances the bioavailability of vitamins and their analogs, thereby improving cellular delivery and therapeutic effects. Vitamin D, known for its crucial role in bone health, also influences various metabolic functions, such as cellular proliferation, differentiation, and immunomodulation, and is increasingly explored for its anticancer potential. Given its versatile properties and biocompatibility, vitamin D is an attractive candidate for encapsulation within drug delivery systems. This review provides a comprehensive overview of vitamin D synthesis, metabolism, and signaling, as well as its applications in customized drug delivery. Moreover, it examines the design and engineering of organic nanocarriers that incorporate vitamin D and discusses advances in this field, including the synergistic effects achieved through the combination of vitamin D with other therapeutic agents. By highlighting these innovations, this review provides valuable insights into the development of advanced drug delivery systems and their potential to enhance therapeutic outcomes.

A Comparison and Safety Evaluation of Micellar versus Standard Vitamin D3 Oral Supplementation in a Randomized, Double-Blind Human Pilot Study

The aim of this pilot study was to evaluate and compare bioavailability and safety of two Vitamin D3 formulations (softgels) in healthy adults, at single daily doses of 1000 and 2500 IU, over a 60-day period. A total of 69 participants were initially screened for eligibility in a double-blind randomized study with a four-arm parallel design; 35 participants were randomized to treatment groups: (1) standard Vitamin D3 1000 IU (STD1000), (2) micellar Vitamin D3 1000 IU (LMD1000), (3) standard Vitamin D3 2500 IU (STD2500), and (4) micellar Vitamin D3 2500 IU (LMD2500). Serum Vitamin D concentrations were determined through calcifediol [25(OH)D] at baseline (=before treatment), at day 5, 10, and 15 (=during treatment), at day 30 (=end of treatment), and at day 45 and 60 (=during follow-up/post treatment). Safety markers and minerals were evaluated at baseline and at day 30 and day 60. The pharmacokinetic parameters with respect to iAUC were found to be significantly different between LMD1000 vs. STD1000: iAUC(5-60): 992 ± 260 vs. 177 ± 140 nmol day/L; p < 0.05, suggesting up to 6 times higher Vitamin D3 absorption of LMD when measured incrementally. During follow-up, participants in the LMD1000 treatment group showed approx. 7 times higher Vitamin D3 concentrations than the STD1000 group (iAUC(30-60): 680 ± 190 vs. 104 ± 91 nmol day/L; p < 0.05). However, no significant differences were found between the pharmacokinetics of the higher dosing groups STD2500 and LMD2500. No significant changes in serum 1,25(OH)2D concentrations or other biochemical safety markers were detected at day 60; no excess risks of hypercalcemia (i.e., total serum calcium > 2.63 mmol/L) or other adverse events were identified. LMD, a micellar delivery vehicle for microencapsulating Vitamin D3 (LipoMicel®), proved to be safe and only showed superior bioavailability when compared to standard Vitamin D at the lower dose of 1000 IU. This study has clinical trial registration: NCT05209425.

Revisiting the significance of nano-vitamin D for food fortification and therapeutic application

OBJECTIVE

Vitamin D (a prohormone) is an important micronutrient required by the body for skeletal homeostasis and a range of non-skeletal actions. Calcitriol, the active form of vitamin D, regulates a variety of cellular and metabolic processes through both genomic and nongenomic pathways. Often prescribed for treating rickets and osteoporosis, vitamin D deficiency can exacerbate various other medical conditions.

SIGNIFICANCE, METHODS, AND RESULTS

Despite its multifunctional uses, the sensitivity of vitamin D makes formulating an efficient drug delivery system a challenging task, which is further complicated by its poor aqueous solubility. Enhancing the oral absorption of vitamin D is vital in utilizing its full efficacy. Recent developments in encapsulation and nanotechnology have shown promising results in overcoming these constraints.

CONCLUSION

This review thus offers an insight to adequately comprehend the mechanistic pharmacology of vitamin D, its pathophysiological role, and justification of its medical indications, along with the benefits of utilizing nanotechnology for vitamin D delivery.