Bioavailability of Two Sustained-release Theophylline Products in Healthy Males

Inclusion Criteria: * Healthy, non-smoking male subjects between 18 and 45 years of age * Body weight within 10% of the ideal weight according to the Body Mass Index (BMI) * Normal health based on medical history and findings within the range of clinical acceptability, in respect of the physical examination (including electrocardiogram and vital signs) and special investigations * Ability to comprehend and willingness to sign both statements of informed consent (for screening and study-specific procedures) Exclusion Criteria: * History of serious systemic or organ disease * A major illness during the 3 months before commencement of the study-related procedures * Significant physical or organ abnormality * History of hypersensitivity to theophylline or other xanthine derivatives * Use of any medication within 2 weeks before the first administration of study medication * Participation in another study with an experimental drug within 8 weeks before the first administration of study medication * Treatment within the previous 3 months with any drug with a well-defined potential for adversely affecting a major organ or system (for example chloramphenicol, which may cause bone marrow suppression) * Donation of blood during the 8 weeks before the first administration of study medication * History of, or current compulsive alcohol abuse (\> 10 drinks per week), of regular exposure to other substance of abuse * Positive testing for HIV and hepatitis B antigens within the previous 3 months