Abstract
BACKGROUND: Nanoemulsion preparations of cholecalciferol available in the market claim to have better bioavailability than the conventional fat-soluble cholecalciferol. However, limited data are available in humans for such preparations. We, therefore, compared the relative bioavailability of two formulations of 60,000 IU cholecalciferol (nanoemulsion oral solution, water-miscible vitamin D3 [test] vs soft gelatin capsules [reference]) in healthy adult participants. METHODS: In this randomized, open-label, two sequence, single-dose, two-way crossover study (CTRI/2018/05/013839), Indian participants aged 18-45 years received single dose of nanoemulsion and capsule formulations, under fasting conditions. Blood samples collected over 120 h were assessed to determine cholecalciferol concentrations. Pharmacokinetic parameters (area under the concentration-time curve up to 120 h [AUC(0-120h)], maximum observed drug concentration [C(max)], time to reach maximum drug concentration [T(max)], terminal half-life [T(½el)], and terminal elimination rate constant [K(el)]) were estimated using baseline corrected data and analyzed using analysis of variance. RESULTS: Among the 24 eligible participants, the relative bioavailability of nanoemulsion was significantly higher than the capsules by 36% (p = 0.0001) based on AUC(0-120h). Similarly, C(max) of the nanoemulsion was significantly higher by 43% (p = 0.0001) than that of the capsules. The intra-participant variability for AUC(0-120h) and C(max) were 23.22% and 26.51%, respectively. The T(max), T(½el), and K(el) were comparable for both the formulations. No adverse effects were noted with either of the two formulations. CONCLUSIONS: Nanoemulsion oral solution of cholecalciferol showed a greater bioavailability compared with soft gelatin capsules, under fasting conditions, in healthy human participants.