Novel Micellar Formulation of Silymarin (Milk Thistle) with Enhanced Bioavailability in a Double-Blind, Randomized,...

Background: Silymarin, a flavonoid complex, and the main bioactive component of milk thistle (Silybum marianum), is known for its hepatoprotective properties but suffers from poor bioavailability due to its low solubility and extensive first-pass metabolism. Method: This study aimed to evaluate the pharmacokinetics and tolerability of a novel micellar milk thistle formulation designed to enhance silymarin absorption, compared to an unformulated/standard milk thistle product, in a small-scale human bioavailability trial. In a randomized, double-blinded, crossover study, 16 healthy participants received a single dose of either the micellar formulation (LipoMicel Milk Thistle; LMM) or the standard formulation (STD) at a total daily dose of 130 mg silymarin. Blood concentrations were measured over 24 h, and key pharmacokinetic parameters-maximum plasma concentration (C_max), time to reach maximum concentration (T_max), and area under the curve (AUC)-were calculated. Tolerability and safety were assessed through adverse event monitoring during the study period. Results: Results demonstrated a significant increase in bioavailability with the micellar formulation, with 18.9-fold higher C_max (95% CI: 1.9-30.7 ng/mL vs. 74.4-288.3 ng/mL; p = 0.007) and 11.4-fold higher AUC_0-24 (95% CI: 7.40-113.5 ng·h/mL vs. 178-612.5 ng·h/mL; p = 0.015). T_max was 0.5 (95% CI: 0.5-4.0) hours for the micellar formulation versus 2.5 (95% CI: 0.5-8.0) hours for the standard product (p = 0.015) indicating faster absorption of LMM. The standard formulation exhibited a significantly longer mean residence time compared to the LMM formulation (95% CI: 4.4-7.5 h vs. 2.8-4.2 h; p = 0.015). Conclusions: No adverse events or significant safety concerns were observed in either group. Compared to the standard, the micellar formulation showed superior pharmacokinetic outcomes, suggesting it may enhance silymarin's clinical efficacy in liver health.