Physiologically-Based Pharmacokinetic Modeling of Fluconazole Using Plasma and Cerebrospinal Fluid Samples From

Jacqueline G Gerhart1, Kevin M Watt2, Andrea Edginton3

  • 1Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.

Insights

This study adapted an adult fluconazole model for infants, accurately predicting drug levels in plasma and cerebrospinal fluid (CSF). A loading dose improved target attainment for treating fungal infections in neonates.

Area of Science:

  • Pharmacokinetics and Drug Metabolism
  • Pediatric Pharmacology
  • Infectious Diseases

Background:

  • Hematogenous Candida meningoencephalitis is a serious infection in infants.
  • Optimizing fluconazole dosing is crucial for effective treatment and minimizing toxicity in neonates.

Purpose of the Study:

  • To characterize fluconazole exposure in infant plasma and central nervous system (CNS).
  • To evaluate the achievement of a surrogate efficacy target using existing dosing guidelines.
  • To adapt an adult physiologically-based pharmacokinetic (PBPK) model for pediatric use.

Main Methods:

  • Scaled an adult fluconazole PBPK model to infants, incorporating age-dependent physiological parameters.
  • Optimized the PBPK model using extensive plasma and cerebrospinal fluid (CSF) sample data from preterm and term infants.
  • Simulated fluconazole concentrations to assess the attainment of the unbound area under the concentration-time curve (AUC) target.

Main Results:

  • The PBPK model demonstrated good predictive accuracy for fluconazole plasma (average fold error 0.73) and CSF concentrations (average fold error 1.14).
  • Simulations indicated that incorporating a 25 mg/kg loading dose accelerated the achievement of target drug exposure in both plasma and CSF.
  • The model successfully predicted fluconazole kinetics across a range of postmenstrual ages.

Conclusions:

  • Physiologically-based pharmacokinetic (PBPK) modeling is a valuable tool for predicting CNS drug exposure in pediatric populations.
  • A loading dose of fluconazole can enhance therapeutic efficacy in infants with Candida meningoencephalitis.
  • This PBPK model provides a foundation for optimizing fluconazole dosing strategies in neonates.

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