Salicylates in saliva

Area of Science:

• Pharmacology
• Drug Metabolism
• Oral Medicine

Background:

• Acetylsalicylic acid (ASA) is a widely used medication.
• Understanding drug excretion and metabolism in saliva is crucial for assessing systemic and local effects.
• Saliva plays a role in drug disposition and oral clearance.

Purpose of the Study:

• To investigate the excretion of acetylsalicylic acid and salicylic acid into human saliva.
• To determine the oral clearance of these salicylates.
• To explore the factors influencing salicylate retention and metabolism in the oral cavity.

Main Methods:

• Administration of 1.0 g acetylsalicylic acid in capsules to human subjects.
• Sham intake of acetylsalicylic acid solution to assess oral clearance.
• In vitro experiments to study salicylic acid binding to salivary proteins.

Main Results:

• Acetylsalicylic acid was not detected in saliva.
• Salicylic acid was excreted into saliva, reaching a maximum concentration of 1.2 µg/ml after 3 hours.
• Significant retention of salicylates occurred in the mouth for 2-3 hours after solution intake, with in-vivo hydrolysis of ASA to salicylic acid.
• In vitro studies showed approximately 50% binding of salicylic acid to salivary proteins at low concentrations, dependent on drug concentration.

Conclusions:

• The absence of acetylsalicylic acid in saliva is attributed to its rapid hydrolysis in the body.
• Protein binding in saliva may contribute to the prolonged oral retention of locally applied salicylates.
• Salicylate retention in the oral cavity has implications for evaluating local analgesic effects and potential bleeding risks.