Nebulized Fentanyl in Healthy Volunteers

Inclusion Criteria: * Age ≥ 18 years and \< 68 years * BMI between 19 and 29 kg/m² * Affiliation to a social security scheme * Adult who has read and understood the information letter and signed the consent form * Woman capable of procreating (a woman is considered capable of procreating, i.e. fertile, after menarche and until she becomes menopausal, unless she is definitely sterile ) having very effective contraception (combined hormonal contraception (containing estrogens and progestins) associated with inhibition of ovulation, progestin-only hormonal contraception associated with inhibition of ovulation, intrauterine device, hormone-releasing intrauterine system (IUS), bilateral tubal occlusion, vasectomized partner, sexual abstinence) for 1 year and a negative urine pregnancy test at inclusion and during the duration of the study. * Woman definitely surgically sterile (hysterectomy, bilateral salpingectomy and bilateral oophorectomy). Postmenopausal woman: The postmenopausal state is defined by the absence of periods for 12 months without any other medical cause. Exclusion Criteria: * Weight \< 50 kg * Taking long-term painkillers or narcotics * Sharp pain * Stable chronic pain (\>3 months, with or without long-term treatment) * Known chronic pathology stabilized or decompensated (hypertension, renal, cardiac, hepatic insufficiency, etc.) * Stable or decompensated chronic respiratory pathology * Chronic neuropsychiatric pathology likely to modify the pain threshold * L…