Dose Proportionality of Different Dose Strengths of Linagliptin Tablets After Oral Administration to Healthy Male and Female Volunteers

Inclusion Criteria: * Healthy male and female volunteers according to the following criteria: Based upon a complete medical history, including the physical examination, vital signs (Blood Pressure (BP), Pulse Rate (PR)), 12-lead ECG (electrocardiogram), clinical laboratory tests * Age 18 to 55 years (inclusive) * BMI (Body Mass Index) 18.5 to 29.9 kg/m2 (inclusive) * Signed and dated written informed consent prior to admission to the study in accordance with Good Clinical Practice and the local legislation Exclusion Criteria: * Any finding of the medical examination (including BP, PR and ECG) deviating from normal and of clinical relevance. Repeated measurement of a systolic blood pressure greater than 140 mmHg or diastolic blood pressure greater than 90 mmHg * Any evidence of a clinically relevant concomitant disease * Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders * Surgery of the gastrointestinal tract (except appendectomy) * Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders * History of relevant orthostatic hypotension, fainting spells or blackouts * Chronic or relevant acute infections * History of relevant allergy/hypersensitivity (including allergy to drug or its excipients) * Intake of drugs within one month or less than 10 half-lives of the respective drug prior to first study drug administration except if a relevant interaction can be ruled out * Participation in another trial with an investigational drug within two months prior to administration or during the trial * Smoker (\> 10 cigarettes or \> 3 cigars or \> 3 pipes/day) * Alcohol abuse ( average consumption of more than 20 g/day in females and 30 g/day in males) * Drug abuse * Blood donation (more than 100 mL within four weeks prior to administration or during the trial) * Any laboratory value outside the reference range that is of clinical relevance * Inability to comply with dietary regimen of trial site For female subjects only: * Positive pregnancy test, pregnancy or planning to become pregnant during the study or within 2 months after study completion * No adequate contraception during the study and until 1 month after study completion, i.e. not any of the following: implants, injectables, combined oral contraceptives, IUD (intrauterine device), sexual abstinence for at least 1 month prior to enrolment, vasectomised partner (vasectomy performed at least 1 year prior to enrolment), or surgical sterilisation (including hysterectomy). Females, who do not have a vasectomised partner, are not sexually abstinent or surgically sterile will be asked to use an additional barrier method (e.g. condom, diaphragm with spermicide) * Lactation