Local gastric and serum amoxicillin concentrations after different oral application forms

Area of Science:

• Pharmacology
• Gastroenterology
• Infectious Diseases

Background:

• High rates of Helicobacter pylori (H. pylori) recolonization after monotherapy suggest insufficient local drug concentrations.
• Amoxicillin exhibits potent in vitro activity against H. pylori, making it a candidate for gastritis treatment.

Purpose of the Study:

• To investigate the role of local drug diffusion in the gastric mucosa.
• To measure amoxicillin concentrations in gastric mucosa and serum following different administration routes.

Main Methods:

• Healthy volunteers received amoxicillin (1g) as a tablet or dissolved in water.
• Gastric biopsies (antrum, corpus, fundus) were collected at 30, 60, and 90 minutes post-administration.
• Mucosal amoxicillin levels were determined using the agar diffusion method; serum concentrations were measured via high-pressure liquid chromatography.

Main Results:

• Amoxicillin concentrations were significantly lower in the fundus and corpus compared to the antrum for both administration forms.
• Bactericidal concentrations in the antrum were achieved in some subjects at 30 minutes, but levels dropped below the minimum bactericidal concentration (MBC) by 60-90 minutes.
• Serum concentrations increased continuously, peaking later than mucosal concentrations.

Conclusions:

• Incomplete eradication of H. pylori may result from sub-bactericidal antibiotic concentrations at the target site.
• Effective H. pylori treatment necessitates adequate local drug diffusion within the gastric mucosa.
• Optimizing drug delivery for enhanced mucosal penetration is crucial for therapeutic success.