薬理と治療

Abstract

Background　Monthly oral ibandronate 100 mg tablet has been developed for the treatment of osteoporosis in Japan. To investigate the pharmacological difference with a fasting interval of 30 minutes（min）compared to a fasting interval of 60 min, clinical pharmacology studies were performed. Methods　This report summarizes the results of two single-center clinical pharmacology studies.One is to investigate the bioavailability of 2.5 mg ibandronate tablet taken 60 min before a meal compared to 2.5 mg ibandronate tablet taken 30 min before a meal, and 5 mg ibandronate tablet taken 30 min before a meal in healthy postmenopausal females. Second is to investigate bioavailability of 50 mg ibandronate tablet taken 60 min before a standard meal compared to 50 mg ibandronate tablet taken 30 min before a standard meal in both healthy males and healthy postmenopausal females. Results　AUClast at fasting interval of 60 min after oral administration of 2.5 mg ibandronate was 1.40±0.77 4 ng・h╱mL （Mean±SD）（n＝24）, that at fasting interval of 30 min after oral administration of 2.5 mg ibandronate was 1.12±0.950 ng・h╱mL（n＝24）, and that at fasting interval of 30 min after oral administration of 5 mg ibandronate was 1.96±1.11 ng・h╱mL（n＝24）. AUClast at fasting interval of 60 min after oral administration of 50 mg ibandronate was 16.0±15.6 ng・h╱mL（n＝24）, that at fasting interval of 30 min after oral administration of 50 mg ibandronate was 11.1±23.5 ng・h╱mL（n＝24）. Conclusions　The relative bioavailability after a single oral dose of 2.5 mg and 50 mg ibandronate as measured by AUClast was lower when the fasting period was shortened from 60 min to 30 min prior to a standard meal. Accordingly, ibandronate should be taken after getting out of bed, before the first food or drink of the day, and food or drink other than water should be avoided for at least 60 minutes after taking ibandronate.