The purpose of this study is to assess the absolute bioavailability of an oral bilastine formulation (test drug) compared to the endovenous administration of an IV bilastine formulation (control drug) in healthy volunteers.

Single centre, open label, cross-over, randomised, controlled, single dose study. The primary endpoint is the determination of plasma concentrations versus time (17 samples per subject at various time intervals after dosing) in order to assess the oral bioavailability of bilastine in healthy volunteers. Therefore the primary pharmacokinetic variable will be the area under the plasma concentration versus time curve from time zero to infinity (AUC 0-∞). Additionally the following pharmacokinetic variables will also be assessed: Cmax, AUC 0-t, tmax, Ae, Clr, t1/2. Additional objectives are to describe the safety and tolerability of a single administration of oral and endovenous bilastine in healthy volunteers.

Twelve healthy volunteers will be included. Each volunteer will take in random order one single dose of 20 mg oral bilastine and 10 mg IV bilastine with a minimum washout period of 14 days between them.

Bilastine plasma concentrations will be measured using a liquid chromatography/mass mass spectrometry (LC/MS/MS) micro method

Inclusion Criteria:

• Healthy volunteers of either sex aged from ≥ 18 to ≤ 35 years of age.
• Body mass index between 19 and 29 Kg/m2.
• Non smokers.
• Judged to be in general good health based on medical history, physical examination and clinical laboratory tests.
• Able to communicate well with the investigator and to comply with the requirements of the entire study.
• Provision of written informed consent to participate.

Exclusion Criteria:

• Pregnant or breast-feeding women or with a positive pregnancy test. Subjects who do not agree to use an adequate method of contraception during the study.
• Intake of another investigational medication in another clinical study within 4 months prior to the first study drug intake.
• Regular use of any prescribed medication including medicinal herbs or OTC medication within 4 weeks of dosing.
• A QTc> 430 ms in males and a QTc> 450 ms in females. A HR <55 bpm.
• Existence of any surgical or medical condition which, in the judgement of the investigator, might interfere with the absorption, distribution, metabolism or excretion of the IMP.
• Known allergy/hypersensitivity to the study drug or its inactive ingredients.
• Any clinical conditions or circumstances that in the opinion of the investigator would make the subject unsuitable for the study (e.g., hepatic impairment, renal impairment, mental impairment, cardiac disease).
• Presence of hepatitis B surface antigen (HBsAg), hepatitis C antibody (HCV Ab) or HIV 1 or HIV 2 antibodies at screening.
• Subjects who have taken metabolic or transporter inducers/inhibitors during the 3 months prior to inclusion in the study.
• Donation or loss of greater than 200 mL of blood within 12 weeks before entry to the study.
• Blood transfusion within the prior 6 months to inclusion.
• Ingestion of citrus fruits and cranberries or any fruit juice within 7 days prior to first dose of study medication.
• Known current alcohol or drug abuse.
• Excessive consumption of xanthine containing foods or drinks.
• Mentally disabled subjects or subjects who by official order have been institutionalised must be excluded from participation.