Pharmacokinetic, Pharmacodynamic and Safety Evaluation After Single Oral Administration of KRN1493

Inclusion Criteria: * Healthy male subjects aged 20 - 35 years * A body mass index (BMI) in the range 19-27 kg/m2 * Sufficient ability to understand the nature of the study and any hazards of participating in it. Provide written informed consent after being fully informed about the study procedures. * Subject who didn't drink grapefruit within 3 days prior to the test drug dosing * Subject judged eligible for study participation by investigator considering screening result except PTH Exclusion Criteria: * Clinically relevant abnormal medical history that could interfere with the objectives of the study. * A subject with history of gastrointestinal disease or surgery (except simple appendectomy or repair of hernia), which can influence the absorption of the study drug. * Presence or history of severe adverse reaction to any drug or a history of severe allergic disease. * Presence or history of drug or alcohol abuse. * Participation in other clinical trial within 3 months (in case of bioequivalence study or other clinical trial) or within 4 months (in case of phase 1 study) or with 1 month (in case of patch) prior to scheduled study drug administration (measured from the final dosing day in the previous trial) * Use of a prescription medicine, herbal medicine or over-the-counter medication within 7 days before first dose * Use of medication or food which induces or inhibits CYP2D6 or CYP3A4 within 1 month prior to the test drug dosing (except food contain grapefruit) * Loss of more than 400 mL blood during the 3 months or 200ml during the 1 month before the study, or apheresis during 2 weeks before the study. * Subject judged not eligible for study participation by investigator