Abcg2 transporter affects plasma, milk and tissue levels of meloxicam

Area of Science:

• Pharmacology
• Molecular Biology
• Drug Metabolism

Background:

• ATP-binding cassette (ABCG2) is a crucial efflux transporter present in various organs, influencing the pharmacokinetics and tissue accumulation of xenobiotics.
• ABCG2 plays a role in the disposition of diverse drugs, including antitumoral, antimicrobial, and anti-inflammatory agents.
• Understanding ABCG2's interaction with drugs is vital for optimizing therapeutic efficacy and minimizing adverse effects.

Purpose of the Study:

• To determine if meloxicam, a common anti-inflammatory drug, is a substrate of the ABCG2 transporter.
• To investigate the impact of ABCG2 on the systemic distribution and pharmacokinetic profile of meloxicam.
• To assess the role of ABCG2 in meloxicam's brain penetration and secretion into milk.

Main Methods:

• Utilized polarized ABCG2-transduced cell lines to assess meloxicam transport by murine Abcg2 and human ABCG2.
• Administered meloxicam orally and intravenously to wild-type and Abcg2 knockout (Abcg2-/-) mice.
• Quantified meloxicam concentrations in plasma, various tissues (including brain), and milk.

Main Results:

• Meloxicam was efficiently transported by both murine Abcg2 and human ABCG2 in cell-based assays.
• Abcg2-/- mice exhibited a 2-fold increase in the area under the plasma concentration-time curve for meloxicam compared to wild-type mice after oral administration.
• A significant 20-fold higher concentration of meloxicam was observed in the brain of Abcg2-/- mice following oral administration, and milk-to-plasma ratios were altered in knockout mice.

Conclusions:

• The ABCG2 transporter is a key determinant of meloxicam's plasma and brain distribution.
• ABCG2 significantly influences the secretion of meloxicam into milk.
• These findings highlight the importance of ABCG2 in the pharmacokinetics and tissue-specific disposition of meloxicam.