College of Pharmacy
63 Establishing an Extraction Protocol for Amphotericin B from Human Plasma
Evan Nayee and Nitish Khurana
Faculty Mentor: Nitish Khurana (Pharmaceutics & Pharmaceutical Chemistry, University of Utah)
Introduction
Extracorporeal membrane oxygenation (ECMO) is a life support technology that assists or, in extreme cases, temporarily takes over for the heart and/or lungs of critically ill patients. ECMO works by pumping a patient’s blood through an oxygenator that introduces oxygen and removes carbon dioxide before the blood is pumped back into the body. ECMO is used to allow the heart and lungs to heal or to bridge the time before the patient receives a transplant1.
By providing more time for their organs to heal, ECMO saves the lives of patients who otherwise would not survive. In spite of its benefits, using ECMO carries several risks, ranging from excess bleeding or clotting to poor blood flow to the limbs (which occasionally results in amputation). The mortality rate of patients on ECMO is upwards of 40%2. One of the biggest challenges with ECMO is properly dosing medication to patients due to drug adsorption2. Drug absorption is when medication adheres to the tubing or oxygenator fibers due to hydrophobic interactions between these components and hydrophobic drugs, removing a portion of the dose from the patient’s bloodstream. Adsorption makes it difficult to know how much of a drug is in circulation where it can treat its target disease versus how much is adsorbed onto the ECMO circuit and, therefore, not contributing to treatment. Without this information, clinicians struggle to ensure patients get the right amount of medication to manage their condition. Some examples of drugs that are prone to adsorption include propofol, midazolam, lorazepam, and fentanyl3,4.
Amphotericin B (AmpB), a member of the polyene class, is an antifungal medication used to treat invasive fungal infections5. In particular, it is used to treat pulmonary fungal infections, which are a serious morbidity in ECMO patients6,7. Due to its significance in ECMO patients, it is important to determine whether AmpB is subject to adsorption.
Herein, we aimed to determine if adsorption occurs when AmpB is administered to ECMO circuits. In particular, the focus was on developing the extraction protocol to be able to quantify AmpB in the blood samples taken during the studies.
Methods
AmpB was dissolved in Dimethyl Sulfoxide (DMSO) at a concentration of 10mg/mL. A UV absorption spectrum was then run, and it was determined that λmax = 409 nm. AmpB was dissolved in Acetonitrile (ACN) or Methanol (MeOH) at a range of desired concentrations for evaluation with UV spectrometry (Concentration range: 10μg/mL-90μg/mL, intervals of 10μg/mL) or High-Performance Liquid Chromatography (HPLC) (Concentration range: 2μg/mL-10μg/mL, intervals of 2μg/mL).
To evaluate the extraction efficiency of AmpB from human plasma, AmpB in DMSO was then added to human plasma to achieve diffe