Nitrous oxide detection - A study in healthy volunteers to help victims of nitrous oxide related crimes

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Aarhus Universitet

Participant type

Healthy volunteers

Age range

18-64 years

Gender

Male and Female

Therapeutic area

Diseases [C] - Nervous System Diseases [C10]

Trial duration

completed 8 Oct 2025

Decision date (initial)

2024-10-22

Transition trial

No

Low-intervention

No

Rare-disease indication

No

Vulnerable population

No

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Pharmacokinetic, Diagnosis

The primary objective is to investigate blood concentrations of N2O after exposure and determine how long N2O can be detected after exposure.

Secondary objectives 7

1. To investigate exhaled breath concentration of N2O after exposure and determine how long N2O can be detected after exposure.
2. To investigate concentration of N2O in urine and saliva after exposure and determine how long N2O can be detected after exposure.
3. To establish an infrared spectroscopy breathalyzer screening method for the detection of N2O.
4. To identify potential biomarkers that can be detected longer than N2O itself in blood or urine using metabolomics analysis
5. To investigate whether urine formiminoglutamic acid can be used as a marker for N2O exposure in humans.
6. To investigate whether changes in homocysteine, methylmalonate, vitamin B12 could be useful as potential biomarkers for N2O exposure.
7. To validate which concentrations of N2O and possible biomarkers that can be detected by the routine screening method on the Department of Forensic Chemistry at Aarhus University.

Conditions and MedDRA coding

Nitrous oxide intoxication

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 4

1. Healthy volunteers aged 18-65 years
2. Informed, written consent
3. Able to understand Danish
4. Participants willing and able to use safe contraception for 24 hours day after gas exposure

Exclusion criteria 1

1. Psychiatric and neurological: • Current or previous substance abuse, N2O abuse or alcohol abuse • A psychiatric disorder that requires medical treatment, incl. major depression • A diagnosis of epilepsy • Symptoms of peripheral neuropathy Cardiopulmonary: • Displaying symptoms of pneumothorax, pneumopericardium, bullous emphysema, gas emboli or severe cranial trauma. • Recent history of coronary artery bypass grafting (CABG) operation with extra corporeal membrane oxygenation (ECMO). • Uncontrolled asthma defined by occurrence of asthma symptoms within the last month prior to inclusion. Anesthesiological: • History of adverse reactions to anaesthesia. • Previous allergic or adverse reaction to N2O • Facial abnormalities that cause a participant to be unable to fit a nasal cannula intended for gas delivery. Occupational: • History of diving within 2 days • Inability to refrain from diving for 2 days following the experiment • Work environmental exposure to N2O • Intake of N2O within the last 3 months Interactions with medications: • Treatment with methotrexate • Treatment with benzodiazepines, opioids, or another CNS-depressant medicinal product • Treatment with physician prescribed vitamin B12 • Recent intraocular injection of gas. Gastroentestital: • Vitamin B12 deficiency • Participant with severely dilated intestines. • History of impaired hepatic or renal function Gynecological/ obstetrical: • Pregnant and breastfeeding women (Fertile women (defined as amenorrhea for less than 12 months) must have a negative HCG pregnancy test prior to intake of the trial medication)

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

1. Time from end of inhalation of study medication to N2O-concentration in blood is no longer statistically significantly increased in the active treatment group compared to the placebo group

Secondary endpoints 6

1. Time until N2O-concentration in exhaled breath is no longer statistically significantly increased in the active treatment group compared to the placebo group
2. Time until N2O-concentration in oral fluid and urine is no longer statistically significantly increased in the active treatment group compared to the placebo group.
3. Time until N2O screening breathalyzer is no longer capable of N2O detection.
4. Time until the longest detectable possible biomarker in blood or urine is no longer up- or downregulated in the active treatment group compared to the placebo group.
5. Time until formiminoglutamic acid is no longer statistically significantly increased in the active treatment group compared to the and placebo group.
6. Verifying that concentration of N2O and possible biomarkers can detected by routine screening at Department of Forensic Medicine, Aarhus University.

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Auxiliary 2

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Aarhus Universitet

Sponsor organisation

Aarhus Universitet

Address

Vennelyst Boulevard 4

City

Aarhus C

Postcode

8000

Country

Denmark

Scientific contact point

Organisation

Aarhus Universitet

Contact name

Department of Forensic Medicine, Aarhus University

Public contact point

Organisation

Aarhus Universitet

Contact name

Department of Forensic Medicine, Aarhus University

Third parties 1

Locations

1 EU/EEA country · 1 investigational sites

By country

Investigational sites

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 10 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

2 submissions — initial application plus substantial / non-substantial modifications