Comparative study of vitamin D2 and D3 pharmacokinetics

SEIJO M ; MASTAGLIA SR ; BRITO GM; KELLER GA; SOMOZA J; DIEZ RA; DIGIROLAMO; OLIVERI B

Otro; XXVIII Reunión Anual Asociación Argentina de Osteología y Metabolismo Mineral; 2011

Some studies found cholecalciferol (D3) to be superior to ergocalciferol (D2) based onthe effect of increasing or maintaining serum 25-hidroxyvitamin-D (25OHD) levels. The aimof this study was to compare D2 and D3 pharmacokinetics. We carried out a single-blind,placebo-controlled randomized trial during 11 weeks (Sept–Dec 2010) in Buenos Aires city.Young healthy volunteers (n=33) with an age of (X±SD) 33.4±6 years were included anddivided into groups: D2 (n=11); D3 (n=11) and placebo (n=11). In the D groups thesubjects received 100,000 IU (baseline) and 4,800 IU/day (d) of the vitamin D allocated from7 to 21 d and no vitamin D, from22 to 77 d. The serum samples were obtained at basal and d:3, 7, 14, 21, 35, 49, 63 and 77. Baseline 25OHD (ng/ml) levels were: D2: 16.3±7; D3: 24.2±6(p<0.01) and placebo: 22.6±7. Placebo values of 25OHD did not increase over treatment,vitamin D administration augmented serum 25OHD levels in each sampling point. To take intoaccount variability in basal 25OHD serum levels, subtraction of basal values was performedbefore pharmacokinetic analysis. For D3-treated subjects, AUC was 1107±481 ng·d/ml(range(r) 331–1920, 95%CI 823–1391), ke−0.246±0.104 day−1(r:−0.479 to−0.125, 95%CI −0.307 to −0.185) and t½ 3.267±1.274 days (r: 1.448–5.545, 95%CI 2.514–4.020). ForD2-treated subjects AUC was 1005±352 ng·d/ml (r: 638–1784, 95%CI 797–1213), ke−0.321±0.245 day−1(r: −0.911 to −0.107, 95%CI −0.466 to −0.176) and t½ 3.105±1.658 days (r: 0.761–6.469, 95%CI 2.124–4.085). Under this administration scheme, nopharmacokinetic differences were found between the two treatments and D2 was equallyeffective as D3 in raising and maintaining 25OHD levels.