Novel intranasal treatment for anxiety disorders using amiloride, an acid-sensing ion channel antagonist: Pharmacokinetic modeling and simulation.

OBJECTIVE To develop a physiologically based pharmacokinetic (PBPK) model for amiloride, an acid-sensing ion channel (ASIC) antagonist, and to simulate its pharmacokinetics in plasma and the central nervous system following intranasal administration in a virtual human population. MATERIALS AND METHODS We first developed a PBPK model of amiloride after oral administration and optimized the model using data from five clinical studies. Next, we added a nasal compartment to the amiloride oral PBPK model and parameterized using data from previous clinical studies. We simulated amiloride's pharmacokinetics in plasma, brain, and cerebrospinal fluid (CSF) after intranasal administration of amiloride at various doses in a virtual human population. RESULTS The target amiloride concentration in the central nervous system required for maximal ASIC inhibition was achieved with a 75-mg intranasal amiloride dose. However, this finding is based on simulations performed using a mathematical model and needs to be further validated with appropriate clinical data. CONCLUSION The nasal PBPK model of amiloride could be used to design future clinical studies and allow for successful clinical translation of intranasal amiloride formulation.