The absolute bioavailability and the effect of food on a new magnesium lactate dihydrate extended-release caplet in healthy subjects.

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 AUC, and 38.11% (fasted) and 40.99% (fed) in urine, based on the GMR of the baseline-adjusted Ae. Relative bioavailability of the caplets comparing the fed and fasted states was 61.67% in serum, based on the GMR of the baseline-adjusted AUC, and 107.57% in urine, based on the GMR of the baseline-adjusted Ae.

CONCLUSIONS

This new magnesium formulation has reasonable bioavailability and might be a valuable addition to the currently available magnesium oral products.