Sublingual Atropine Bioequivalence by Route of Administration (SABER)

A randomized, two-period, two-sequence, crossover study to assess the bioequivalence, bioavailability, and pharmacokinetics (PK) of a single dose of atropine administered sublingually (SL) or intramuscularly (IM) in healthy adult volunteers.

This is a randomized, two-period, two-sequence, crossover study to assess the bioequivalence, bioavailability, and pharmacokinetics (PK) of a single dose of atropine administered SL or IM in healthy adult volunteers. A total of 46 healthy male and non-pregnant female volunteers will be randomized, with the goal of obtaining at least 36 evaluable participants in the per protocol population. Additional participants may be randomized if participants are withdrawn prior to receiving one or both doses of study drug. Eligible participants will be randomized at a 1:1 ratio to receive one of two treatment dosing sequences (A \[Visit 1 SL, Visit 2 IM\] or B \[Visit 1 IM, Visit 2 SL\]).

Volunteers will be screened for study participation from Days -14 to -3. Eligible participants will be enrolled and randomized to receive one of two dosing sequences (Sequence A or Sequence B) until the target enrollment for the study is met. Once randomized, each participant will receive 2 doses of atropine separated by a wash out period of 6 ±1 days. During Visit 1 (Day 1) and Visit 2 (Day 8), participants will be administered SL or IM atropine, according to their randomly assigned dosing sequence. At each dosing visit, blood samples for PK will be collected at time 0 (pre-dose) and at 13 time points post-dose at 5, 10, 15, 20, 30, 45, 60, and 90 minutes and 2, 2.5, 4, 6, and 8 hours after dosing. Participants will be discharged from the clinic after the 8-hour blood sample collection. Participants will be followed for approximately 6 days after their last dose.

Eligibility Criteria:
Inclusion Criteria:

1. Healthy male and non-pregnant female volunteers between the ages of 18 and 65 years, inclusive, at time of consent.
2. Willing and able to provide written informed consent.
3. Females who are of childbearing potential and are sexually active with a male partner must have used an adequate method of birth control for at least 2 months prior to Screening and must agree to continue using an adequate method of birth control from Screening through Follow-up (Day 15).

   1. A female of childbearing potential is defined as a post onset of menarche and premenopausal female capable of becoming pregnant. This does not include females who meet any of the following conditions: menopausal \>2 years, tubal ligation \>1 year, bilateral salpingo-oophorectomy, or hysterectomy.
   2. Adequate contraception is defined as a contraceptive method with a failure rate of less than 1% per year when used consistently and correctly and when applicable, in accordance with the product label. Examples include oral contraceptives, injectable progestogen, implants of etonogestrel or levonorgestrel, estrogenic vaginal ring, percutaneous contraceptive patches, intrauterine device or intrauterine system, or male partner sterilization at least 6 months prior to the participant's Screening Visit.
4. In the judgment of the investigator, the participant is in good health, based on review of medical history and the results of Screening evaluation (including vital signs, physical examination, 12-lead electrocardiogram \[ECG\], and Screening laboratory assessments, performed no more than 14 days prior to randomization into the study).
5. Able to comply with the dosing instructions and available to complete the study Schedule of Assessments.

Exclusion Criteria:

1. Females who have a positive pregnancy test or who are breastfeeding.
2. Participants with thyroid disease as evidenced by a thyroid-stimulating hormone (TSH) \<0.9 × lower limit of normal (LLN) or \> 1.2 × upper limit of normal (ULN) at Screening (This Screening test will not be repeated prior to subsequent dosing).
3. Participants with aspartate aminotransferase (AST), alanine aminotransferase (ALT), or serum creatinine \>1.5 × ULN at Screening. (These Screening tests will not be repeated prior to subsequent dosing.)
4. Have known human immunodeficiency virus (HIV), or acute or chronic hepatitis B or hepatitis C infection based on medical history; or test positive for any of these at Screening. Participants who have been effectively treated for hepatitis C, as evidenced by a negative hepatitis C RNA confirmation test and who no longer require antiviral therapy, are eligible for participation. (These Screening tests will not be repeated prior to subsequent dosing.)
5. Participants who took any prescription medications (with the exception of oral contraceptives or hormone replacement therapy) within 30 days of Screening. Prior to each dose, the investigator will review prohibited medication use and determine whether the participant should be terminated from further dosing.
6. Participants who took any over-the-counter medication/vitamins/herbal supplements in the last 72 hours prior to Screening. Prior to each dose, the investigator will review prohibited medication use and determine whether the participant should be terminated from further dosing.
7. Participants who are current smokers or are currently using any oral nicotine/oral tobacco product (e.g. snuff, chew, lozenges, nicotine gum, pouches) or electronic cigarette or vaping device (e.g., e-cigarette, mod, vape pen, JUUL, e-cigar, e-hookah, e-pipe, vape pods) or have used any of these products within 6 months prior to Screening.
8. Participants with glaucoma and/or history of ocular surgery (including LasikTM), ocular trauma, or congenital ocular disorder.
9. Participants with any history of heart disease, including but not limited to hypertension, coronary artery disease, arrhythmia (treated or untreated), congestive heart failure, pacemaker, history of vasovagal syncope, any supraventricular tachycardia, peripheral vascular disease, or claudication.
10. Participants with clinically significant arrhythmias or abnormal conduction; abnormal conduction is defined as a prolonged PR or QRS, or a QTc ≥450 msec for males or ≥470 msec for females.
11. Participants with a history of partial organic pyloric stenosis, chronic constipation, gastroparesis, or other gastrointestinal motility issues.
12. Participants with a history of xerostomia due to an underlying disease or previous radiation therapy to the head and neck.
13. Males with history of symptomatic prostatic hypertrophy; males or females with a history of urinary hesitancy or retention.
14. Participants with a blood pressure \>140/90 mm Hg taken after the participant has been seated and resting for at least five minutes.
15. Participants with a history or current diagnosis of myasthenia gravis.
16. Participants who have donated blood within 8 weeks of Screening or intend to donate blood during the study period.
17. Participants with a history of drug or alcohol abuse in the last two years or evidence of a positive urine drug test at Screening. (This Screening test will not be repeated prior to subsequent dosing.)
18. Participants with a known sensitivity or prior adverse reaction to atropine.
19. Participants who have consumed alcohol within 24 hours prior to each Pre-dose Visit. (This will be assessed only at Visit 1 \[Pre-dose\] and Visit 2 \[Pre-dose\].)
20. Participants with any other condition that, in the opinion of the investigator, would pose a health risk to the participant if enrolled, would interfere with SL or IM administration of study drug, or would otherwise interfere with interpretation of study results.