Bioavailability study of fosfosal and codeine administered alone or in combination

Area of Science:

• Pharmacology
• Drug Development

Background:

• Fosfosal (2-phosphonoxybenzoic acid) is a salicylic acid derivative for inflammatory conditions and pain relief.
• Codeine, often combined with acetylsalicylic acid, manages mild to moderate pain.

Purpose of the Study:

• To evaluate the pharmacokinetic profiles of fosfosal and codeine when administered alone versus in combination.
• To assess the bioavailability and drug interactions between fosfosal and codeine.

Main Methods:

• Ten healthy subjects received single oral doses of fosfosal (1,200 mg) and codeine (30 mg), alone and combined.
• Plasma concentrations of salicylic acid and codeine were measured using HPLC and enzyme immunoassay.
• Pharmacokinetic parameters, including Cmax, AUC, and tmax, were calculated and compared.

Main Results:

• No significant differences in Cmax and AUC for codeine when combined with fosfosal.
• Increased tmax (time to reach peak concentration) observed for both fosfosal and codeine when administered together.
• Minor statistical differences in elimination rate and MRT for codeine were not clinically significant.

Conclusions:

• The pharmacokinetic data support the co-administration of fosfosal and codeine.
• The observed changes in bioavailability suggest a single-formulation approach is viable for these analgesics.