The purpose of the study was to investigate the pharmacokinetics (i.e. the uptake, distribution and elimination from the body) of dermally applied buprenorphine during and after different application periods, i.e., a 96-hour and a 72-hour application of the Transtec (Registered Trademark) patch (release rate 35 micrograms per hour [µg/hour]). In the Transtec summary of product characteristics (prescribing information for the physician), the wearing time per patch is restricted to three days (72 hours) after which the patch has to be replaced. However, market experience has shown that the Transtec patches are sometimes worn for a period longer than three days, i.e. they sometimes happen to be only replaced every four days. There was currently no data available as how to evaluate this longer wearing period.

Inclusion Criteria:

• Male Caucasian volunteers, aged 25-45 years.
• Body mass index (BMI) between 18 and 30 kilogram/squared meter (extremes included).
• Good physical and mental health status (no current acute illness) determined on the basis of the medical history and a general clinical examination.
• Systolic blood pressure between 90 millimeter mercury (mmHg) and 150 mmHg (extremes included).
• Diastolic blood pressure between 45 mmHg and 90 mmHg (extremes included).
• Pulse rate between 45 beats per minute (bpm) and 100 bpm (extremes included).
• Electrocardiogram (12 lead) considered as normal by the investigator.
• Results of laboratory tests within the normal ranges for the testing laboratory. The investigator may include a participant having values outside the accepted range if, in his/her opinion, these values are of no clinical relevance. The decision will be justified.
• The participant has been informed using the informed consent approved by the local ethics committee.
• The consent was obtained by participant's signature.

Exclusion Criteria:

• Diseases and functional disorders of the central nervous system (CNS), endocrinological system, gastrointestinal tract, hepatobiliary system, renal system, respiratory system or cardiovascular system including marked repolarization abnormality (e.g. suspicious or definite congenital long QT syndrome) or co-medication that is known to influence cardiac repolarization substantially.
• History of seizures or at risk (i.e. head trauma, epilepsy in family anamnesis, unclear loss of consciousness).
• Malignancy.
• History of orthostatic hypotension.
• Positive human immunodeficiency virus (HIV) 1/2-antibodies, hepatitis B surface (HBs) -antigen, hepatitis B core (HBc) -antibodies, hepatitis C virus (HCV) -antibody tests at the screening examination.
• Drug allergy.
• Bronchial asthma.
• Participation in another clinical study within three month prior to the start of this study (exception: characterization of metabolizer status).
• Blood donation (more than 100 milliliters) within three month prior to the start of this study.
• Use of any medication within four weeks prior to the start of the study (self-medication or prescription).
• Evidence of alcohol, medication or drug abuse.
• Positive Naloxone challenge test.
• Positive drug abuse screening test.
• Extremely unbalanced diet (in the opinion of the investigator).
• Excessive consumption of food or beverages containing caffeine or other xanthines (more than five cups of coffee or equivalent per day).
• Smoking of more than 20 cigarettes per day.
• Neurotic personality, psychiatric illness or suicide risk.
• Known or suspected of not being able to comply with the study protocol.