Inclusion Criteria:  Informed consent: signed written informed consent before inclusion in the study Sex and Age: men/women, 18-55 years old inclusive Tobacco: non-smokers for at least 6 months prior to study screening Body Mass Index (BMI): 18.5-29 kg/m2 inclusive Vital signs: systolic blood pressure (SBP) 100-139 mmHg, diastolic blood pressure (DBP) 50-89 mmHg, heart rate 50-90 bpm, measured after 5 min at rest in the sitting position Full comprehension: ability to comprehend the full nature and purpose of the study, including possible risks and side effects; ability to co-operate with the investigator and to comply with the requirements of the entire study  Contraception and fertility (women only): women of child-bearing potential must be using at least one of the following reliable methods of contraception:  A non-hormonal intrauterine device or female condom with spermicide or contraceptive sponge with spermicide or diaphragm with spermicide or cervical cap with spermicide for at least 2 months before the screening visit A male sexual partner who agrees to use a male condom with spermicide A sterile sexual partner Female participants of non-child-bearing potential or in post-menopausal status for at least 1 year will be admitted. For all women, pregnancy test result must be negative at screening.  Exclusion Criteria:  Electrocardiogram (ECG) 12-leads: (supine position) clinically significant abnormalities; corrected QT interval > 450 msec Physical findings: clinically significant abnormal physical findings which could interfere with the objectives of the study Laboratory analyses: clinically significant abnormal laboratory values indicative of physical illness Cotinine: positive cotinine test at screening Allergy: ascertained or presumptive hypersensitivity to the active principle and/or formulations' ingredients; history of anaphylaxis to drugs or allergic reactions in general, which the investigator considers may affect the outcome of the study Diseases: clinically significant history or presence of renal, hepatic, gastrointestinal, cardiovascular, cerebrovascular, immunological, musculoskeletal, respiratory, skin, haematological, endocrine, psychiatric or neurological diseases or surgeries that may interfere with the aim of the study. Gastrointestinal pathologies include any clinically significant disorder of the mouth, e.g. impairment of swallowing, lesions, ulcerations, deformities, untreated dental caries Dentures: presence of mouth jewellery, dentures, braces, piercings that may interfere with successful completion of the dosing Medications: medications, including over the counter medications and herbal remedies for 2 weeks before study screening; central nervous system depressants, including opioids, benzodiazepines, general anaesthetics and anticonvulsants, or cytochrome C inhibitors, including cimetidine, fluoxetine, quinidine, erythromycin, ciprofloxacin, fluconazole, ketoconazole, diltiazem and antiretroviral agents, or strong cytochrome C inducers, including barbiturates, carbamazepine, glucocorticoids, phenytoin, St John's wort and rifampin, or hormonal oral or transdermal contraceptives for 30 days before study screening; implanted, injected, intravaginal or intrauterine hormonal contraceptives for 6 months before study screening Investigative drug studies: participation in the evaluation of any investigational product for 3 months before this study. The 3-month interval is calculated as the time between the first calendar day of the month that follows the last visit of the previous study and the first day of the present study Blood donation: blood donations for 3 months before this study Drug, alcohol, caffeine, tobacco: history of drug, alcohol [>1 drink/day for females and >2 drinks/day for males, defined according to the Dietary Guidelines 2015 ], caffeine (>5 cups coffee/tea/day) or tobacco use including any tobacco product like e-cigarettes and vamping products Drug test: positive result at the drug test at screening or Day -1 Alcohol test: positive alcohol breath test at Day -1 Diet: abnormal diets (<1600 or >3500 kcal/day) or substantial changes in eating habits in the 4 weeks before this study; vegetarians and vegans Pregnancy (women only): positive or missing pregnancy test at screening or Day -1, pregnant or lactating women