Flunoxaprofen pharmacokinetics in elderly subjects.

Area of Science:

• Pharmacology
• Geriatric Medicine

Background:

• Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for pain and inflammation.
• Understanding drug pharmacokinetics in elderly populations is crucial due to potential age-related physiological changes.

Purpose of the Study:

• To investigate the plasma kinetics and urinary elimination of flunoxaprofen in elderly patients.
• To compare flunoxaprofen pharmacokinetics between elderly patients and young volunteers.

Main Methods:

• Single oral administration of 100 mg flunoxaprofen to 23 elderly patients and 4 young volunteers.
• Plasma and urine concentrations measured using high-performance liquid chromatography (HPLC).
• Analysis of pharmacokinetic parameters including half-life, peak plasma concentration, AUC, total clearance, and MRT.

Main Results:

• Flunoxaprofen plasma kinetics followed a 3-exponential equation with a mean half-life of 7.9 hours.
• Mean peak plasma concentration was 8.5 µg/ml, observed around 2 hours post-dose.
• High inter-individual variability in AUC and clearance was linked to body weight; AUC correlated linearly with dose/body weight.
• About 10% of the drug was excreted unchanged in urine, indicating significant biotransformation.
• Elderly patients showed slightly slower gastrointestinal absorption and a longer mean residence time compared to young volunteers.

Conclusions:

• Flunoxaprofen exhibits substantial biotransformation, with minimal unchanged drug excreted in urine.
• Pharmacokinetics of flunoxaprofen in elderly patients are broadly similar to young adults, with minor differences in absorption and residence time.
• Body weight is a significant factor influencing flunoxaprofen's area under the curve and clearance in elderly individuals.