(M1230-11-63) Single-Dose Pharmacokinetics of Intranasal Amiloride in Healthy Volunteers

Purpose: The purpose of this study is to evaluate the single-dose pharmacokinetics of amiloride after intranasal administration in healthy volunteers. In our preclinical studies, we showed that amiloride can reduce anxiety symptoms in mice and can potentially be developed as a therapeutic to treat anxiety in humans¹. Subsequently, we developed an intranasal formulation of amiloride and evaluated its chemical and microbiological stability². As a next step toward the translation of intranasal amiloride, we performed a pharmacokinetic study of intranasal amiloride at 0.6 mg dose in healthy human volunteers.

Methods: This single-dose pharmacokinetic study was approved by the Food and Drug Administration (FDA) as an Investigational New Drug (IND) Application (IND#14445) and the Institutional Review Board, University of Utah, Salt Lake City, Utah. Five healthy volunteers aged 18 to 40 years were enrolled in the study. 0.6 mL of 0.01% Amiloride solution (0.6 mg total dose) was administered to volunteers using an intranasal mucosal atomization device (MAD Nasal^TM). The safety of the volunteers after intranasal administration of amiloride was evaluated by performing biochemical, hematological, and cardiovascular tests. The local toxicity of intranasal amiloride was evaluated by performing an anterior rhinoscopy of the nasal cavity. Blood samples were collected by venipuncture at time points 0, 10 mins, 15 mins, 30 mins, 1, 2, 4, 6, 8, and 24 hours. The plasma was immediately separated from the blood and sent to the lab for analysis to quantify amiloride concentration. The amiloride concentration was calculated in the plasma samples using a validated ultra-high-performance liquid chromatography (UHPLC) - electrospray ionization (ESI) - tandem mass spectrometry (UHPLC-ESI-MS/MS). The pharmacokinetic parameters were calculated by noncompartmental analysis from the plasma concentration versus time data. The noncompartmental analysis was performed using statistical software R.

Results: In all five participants, amiloride levels were detected in plasma samples 10 minutes after intranasal administration. The amiloride plasma concentration versus time profiles of individual participants is provided in Figure 1. The average T_max (time to reach maximum concentration) was 4.83 hours and the average C_max (maximum plasma concentration) was 1.62 ng/mL. The values of other PK parameters (AUC, Vd, T_1/2, etc.) are provided in Table 1. The biochemical, hematological, and cardiovascular tests showed that amiloride nasal spray is safe and does not cause toxicity. The anterior rhinoscopy data showed that intranasal amiloride did not cause any local toxicity in the nasal cavity.

Conclusion: In conclusion, our amiloride formulation reached systemic circulation rapidly within 10 minutes after intranasal administration in humans. The amiloride nasal spray did not show any systemic or local toxicity in humans at the 0.6 mg dose. Due to the rapid absorption of amiloride into the systemic circulation and favorable local and systemic toxicity profile, intranasal amiloride can be further developed as a therapeutic agent to treat anxiety.

References: 1. Battaglia M, Rossignol O, Bachand K, D'Amato FR, De Koninck Y. Amiloride modulation of carbon dioxide hypersensitivity and thermal nociceptive hypersensitivity induced by interference with early maternal environment. J Psychopharmacol. 2019 Jan;33(1):101-108.
2. Yellepeddi V, Sayre C, Burrows A, Watt K, Davies S, Strauss J, Battaglia M. Stability of extemporaneously compounded amiloride nasal spray. PLoS One. 2020 Jul 10;15(7):e0232435.

Acknowledgments: This study was funded by Discovery Grant from Centre for Addiction and Mental Health, Canada.

Figure 1. Plasma concentration versus time profiles of 0.6 mg intranasal amiloride in five healthy volunteers



Table 1. PK parameters calculated by noncompartmental analysis of 0.6 mg amiloride intranasal spray in healthy volunteers