Cebranopadol Effects on Ventilatory Drive, Central Nervous System (CNS) and Pain.

Inclusion Criteria:

1. Signed informed consent prior to any study-mandated procedure.
2. Subject is able to speak, read, and understand Dutch and voluntarily provide writteninformed consent to participate in the study.
3. Adult men or women aged 18 to 45 years, inclusive.
4. Subjects are in good health as indicated by medical history, physical examination,vital signs, oxygen saturation, clinical laboratory tests, and 12-lead ECG.
5. Body mass index between 18.0 kg/m2 and 32.0 kg/m2 and body weight greater than 50 kg,inclusive.
6. Adequate contraception is being used or women of nonchildbearing potential may beenrolled if surgically sterile (i.e., after hysterectomy) or postmenopausal for atleast 2 years (based on subject's report).

Exclusion Criteria:

1. History or presence of clinically significant cardiovascular (incl. a history of riskfactors for torsade de pointes e.g., heart failure, hypokalaemia, family history oflong QT syndrome, history of myocardial infarction, ischaemic heart disease,clinically significant arrhythmia or uncontrolled arrhythmia or cardiac failure),pulmonary, hepatic, renal, hematologic, gastrointestinal, endocrine, immunologic,dermatologic, neurologic, oncologic, or psychiatric disease (e.g., anxiety); or anyother condition (e.g., hyperventilation disorder), which, in the opinion of theInvestigator, would jeopardize the safety of the subject or the validity of the studyresults.
2. History of known difficult airway access or uncontrolled gastroesophageal refluxdisease (GERD), gastric motility disorders, or delayed gastric emptying
3. Has clinically significant abnormalities on ECG at screening or Day -1, as defined bythe following:
4. prolonged corrected QT interval (Fridericia-corrected QT interval [QTcF] >450 msin males and >470 ms in females) demonstrated on ECG;
5. Left bundle branch block at Screening or Baseline
6. Systolic blood pressure (BP) >150 or <90 mmHg or diastolic BP >90 or <50 mmHg atScreening or Baseline, or history of clinically significant orthostatic hypotension.
7. Heart rate (HR) <40 beats per minute (bpm) or >100 bpm at Screening.
8. Is currently enrolled in another clinical study or used any investigational drug ordevice within 3 months prior to dosing or has participated in more than 4investigational drug studies within 1 year prior to Screening.
9. Has any condition in which an opioid is contraindicated (e.g., significant respiratorydepression, acute or severe bronchial asthma or hypercarbia, or has or is suspected ofhaving paralytic ileus).
10. Have a history of chronic obstructive pulmonary disease or any other lung disease (e.g., asthma, bronchitis, obstructive sleep apnoea, exercise-induced asthma) thatwould cause CO2 retention.
11. History of opioid use disorder per Diagnostic and Statistical Manual of MentalDisorders, Fifth Edition (DSM-5) classification, or other drug/substance or alcoholdependency or abuse (excluding nicotine and caffeine) within the last 5 years beforeScreening.
12. Has a positive alcohol test or urine drug screen for drugs of abuse (amphetamines,methamphetamines, barbiturates, benzodiazepines, cocaine, and opioids) at Screening orDay -1.
13. Use of nicotine-containing products within 4 weeks before the Screening visit and notable to withhold from smoking during the study.
14. Pregnant or breastfeeding.
15. Subjects indicating pain test intolerability at Screening or achieving pain toleranceat >80% of maximum input intensity for the pain tests.
16. Demonstrated allergic reactions (e.g., food, drug, atopic reactions, or asthmaticepisodes) which, in the opinion of the Investigator, interfere with the subject'sability to participate in the trial.
17. Positive hepatitis B surface antigen (HBsAg), hepatitis B core antibodies (Anti-HBc),hepatitis C antibodies (HCV Ab), or human immunodeficiency virus antibody (HIV Ab) atScreening.
18. Use of prescription, non-prescription medications or herbal preparations containingSt. John's Wort, within 14 days or 5 half-lives prior to dosing, whichever is longer.An exception is made for contraceptives and incidental use of paracetamol oribuprofen, which is allowed up to 48 hours before start of each visit. Otherexceptions are allowed only when clearly documented by the investigator.
19. No vitamin, mineral, herbal, and dietary supplements will be permitted within 7 daysprior to study drug administrations, or less than 5 half-lives (whichever is longer,and during the course of the study.
20. Any clinically significant lifetime history of suicidal behaviour or ideation and/orposes a current (within the past 12 months) suicide risk, as assessed by scores on theColumbia Suicide Severity Rating Scale (C-SSRS) at Screening per Investigator judgment
21. Receipt of blood products within 4 weeks, blood donation or blood loss >250 mL within 8 weeks, or donation of plasma within 1 week of any Study Drug dose administration.
22. Is employed by Tris, Park, the Centre for Human Drug Research (CHDR), or theInvestigator or study site (permanent, temporary contract worker, or designeeresponsible for the conduct of the study), or is immediate family* of a Tris, Park,CHDR, Investigator, or study site employee.