Optimal storage temperature and matrix before analyzing mycophenolic acid

Area of Science:

• Pharmacology
• Clinical Chemistry
• Transplantation Medicine

Background:

• Mycophenolic acid (MPA) is a crucial immunosuppressant for organ transplant recipients.
• Therapeutic drug monitoring of MPA is limited by sample transport delays and unknown stability.
• Limited data exists on MPA stability in whole blood and plasma under various storage conditions.

Purpose of the Study:

• To assess the stability of MPA in patient whole blood and plasma samples.
• To determine optimal sample types and transport conditions for accurate MPA therapeutic drug monitoring.

Main Methods:

• Whole-blood and plasma samples were stored at various temperatures ( -20°C, 4°C, 21°C, 35°C) for up to 4 weeks.
• MPA concentrations were measured using liquid chromatography-tandem mass spectrometry.
• Stability was evaluated under conditions mimicking typical laboratory transit times and temperatures.

Main Results:

• Whole blood showed increased MPA concentrations over time, particularly at 35°C.
• Plasma samples were stable for 28 days at 4°C and -20°C.
• Plasma MPA concentrations increased progressively at 21°C and showed complex changes at 35°C.

Conclusions:

• Promptly separate plasma from whole blood after collection.
• Store plasma samples at -20°C or 4°C for transport.
• Utilize subambient temperatures during transport to ensure MPA stability.