A Study to Assess the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of FlecIH-101 Versus Placebo in Healthy Volunteers

INTERVENTION: A single 90 mg dose of FlecIH‐101 (flecainide acetate inhalation solution) administered via oral inhalation in 3 inhalation stages, each lasting 3.5 minutes, with approximately 30‐second breaks in between each inhalation. Monitoring of adherence to the inhalation procedure will be done by direct observation by study personnel. If participants provide specific written consent, a video recording will also be taken of the inhalation procedure. CONDITION: Paroxysmal atrial fibrillation PRIMARY OUTCOME: To evaluate the safety and tolerability of a single 90mg dose of FlecIH‐101 compared to placebo in healthy volunteers. This will be assessed by looking at the incidence, severity, causality and seriousness of adverse events; changes in clinical laboratory evaluations; changes in vital signs parameters, physical examinations; and ECGs (electrocardiograms). SECONDARY OUTCOME: Pharmacodynamics of the 90 mg dose of FlecIH‐101 by measuring electrocardiogram (ECG) intervals (QRS interval, PR interval, QTc, and JTc) following administration of FlecIH‐101 in healthy volunteers Pharmacokinetics (Cmax, Tmax, AUC0‐24, AUCinf, 97kel, and T1/2) of the 90 mg dose of FlecIH‐101 in plasma following administration of FlecIH‐101 in healthy volunteers INCLUSION CRITERIA: 1. Male or female, 18 to 55 years of age (inclusive), at the time of screening; 2. Agree to use protocol specified method(s) of contraception, if a male participant or a female participant of childbearing potential who engages in heterosexual intercourse; 3. Agree to refrain from egg or sperm donation for the duration of the study; 4. Able and willing to sign the informed consent as approved by the Human Research Ethics Committee (HREC); 5. Have a body mass index (BMI) between 20 and 32 kg/m2 and a BW greater than or equal to 55 kg; 6. No significant medical history, and in good general health; 7. Have no electrocardiographic abnormalities during a 12‐lead ECG screening that, in the opinion of the PI (or delegate), may compromise the participant’s safety in the study; 8. Have no clinically significant abnormalities detected on a standard diagnostic echocardiogram; 9. Be non‐smokers (including tobacco, e‐cigarettes and marijuana) with