Abstract: | Cats and dogs can suffer from multiple autoimmune diseases. Mycophenolic acid (MPA) is a potentially useful immunosuppressant drug in cats and dogs, because of its well‐documented efficacy in controlling autoimmune disease in humans. However, the pharmacokinetics and pharmacodynamics in these species remain to be determined. We have developed and validated a sensitive, precise, accurate and reproducible method that provides consistent quantification of MPA and its major derivatives, MPA phenol glucoside and MPA phenol glucuronide, in canine and feline plasma using ultra‐high‐pressure liquid chromatography coupled to an ultraviolet detector. The main advantages of this novel method include a small sample volume, easy sample preparation, a short chromatographic analysis time and the option to select either phenolphthalein β ‐d ‐glucuronide or mycophenolic acid carboxybutoxy ether as internal standard. Results of validation indicate that this analytical method is suitable to study the plasma disposition of MPA and its derivatives in dogs and cats. |