Objective: To assess the absolute bioavailability of 20 mEq magnesium lactate extended-release (ER) caplets and to assess the effect of food on the pharmacokinetics of these ER caplets.
Significance: Magnesium in different salt forms is available as over-the-counter oral formulations. The absorption and bioavailability is highly affected by the water solubility of the salt form. A new ER caplet of 10 mEq strength of magnesium L-lactate dihydrate has been developed to increase the bioavailability of magnesium.
Methods: An open label, single-dose, randomized, three-period, cross-over study in healthy adults was conducted with three treatments: (a) single oral dose of 20 mEq magnesium L-lactate dehydrate under fasting conditions, (b) single intravenous (IV) infusion of 20 mEq magnesium sulfate, and (c) single oral dose of 20 mEq magnesium L-lactate dehydrate under fed conditions. Urine and blood samples were collected for analysis of urinary and serum magnesium concentrations.
Results: Absolute bioavailabilities of the caplets under fasted and fed conditions, compared to IV magnesium sulfate, were 20.26% (fasted) and 12.49% (fed) in serum, based on the geometric mean ratio (GMR) of the baseline-adjusted AUC0-72, and 38.11% (fasted) and 40.99% (fed) in urine, based on the GMR of the baseline-adjusted Ae0-72. Relative bioavailability of the caplets comparing the fed and fasted states was 61.67% in serum, based on the GMR of the baseline-adjusted AUC0-72, and 107.57% in urine, based on the GMR of the baseline-adjusted Ae0-72.
Conclusions: This new magnesium formulation has reasonable bioavailability and might be a valuable addition to the currently available magnesium oral products.
Keywords: Hypomagnesemia; dietary supplement; extended-release; food effect; magnesium; pharmacokinetics.