Fasting increases tobramycin oral absorption in mice

Area of Science:

• Pharmacology
• Drug Delivery
• Gastroenterology

Background:

• Aminoglycosides like tobramycin are poorly absorbed orally.
• Oral drug bioavailability is influenced by gastrointestinal conditions, including feeding status.

Purpose of the Study:

• To investigate the impact of fasting on tobramycin pharmacokinetics.
• To determine if fasting enhances oral absorption of tobramycin in mice.

Main Methods:

• Tobramycin was administered orally to fed and 15-hour fasted mice.
• Pharmacokinetic parameters were evaluated.
• Small bowel permeability was assessed using a dual-sugar (lactulose and l-rhamnose) test.

Main Results:

• Oral absorption of tobramycin was negligible in fed mice.
• Fasting led to a significant increase in tobramycin bioavailability.
• Fasting increased small bowel permeability via the paracellular route.

Conclusions:

• Fasting dramatically improves oral bioavailability of tobramycin.
• Increased small bowel permeability contributes to enhanced absorption.
• Accurate timing of fasting is essential for optimizing oral delivery of hydrophilic drugs.