A Proof-Of-Concept (POC) Study of SFG-02 Transdermal Formulation in Participants With Underactive Bladder (UAB)

Inclusion Criteria: * Participants must have at least 2 out of 3 symptoms of UAB (urinary hesitancy, straining to void, and/or weak urinary stream) for at least 3 months before entering the study * Participants must meet the criteria for the study based on uroflowmetry assessments, ultrasound scans of the bladder, and a urodynamics study assessment at study entry * If the participant uses clean intermittent self-catheterization (CISC), the participant must have been using CISC continuously for at least 3 months, and must not be completely dependent on CISC to empty their bladder * Participants must have adequate kidney, liver, and heart function based on laboratory blood tests and electrocardiograms Exclusion Criteria: * Participants with clinically significant obstructions of lower urinary tract * Participants with an upper or lower urinary tract infection, or a genital infection * Participants with one or more bladder diverticula or any other condition that may affect the measurement of post-void residual (PVR) urine volume * Participants with calculi (stones) in the ureter, bladder, or urethra * Participants with vesicoureteral and/or renal reflux * Participants with hydronephrosis * Participants with an indwelling urinary catheter * Participants who rely on voiding assistance maneuvers to facilitate urination * Participants with moderate-to-severe overactive bladder, defined by an OABSS, or participants with overactive bladder requiring treatment * Participants with a low-compliance bladder * Participants who are currently taking medications for voiding dysfunction * Participants with increased pelvic floor muscle activity during voiding * Participants with a history of bladder surgery * Participants who have undergone surgery for urethral obstruction due to Benign Prostatic Hyperplasia (BPH) or for pelvic organ prolapse within the past 6 months * Participants who have undergone surgery for urinary incontinence or any other pelvic surgery within the past 12 months * Participants with chronic pelvic pain that may affect uroflowmetry results * Participants with a history of pelvic radiation therapy * Participants with overflow urinary incontinence