BACKGROUNDCombined treatment with a bisphosphonate and vitamin D has been proposed for postmenopausal osteoporosis. A new, fixed-dose combination tablet of ibandronate plus vitamin D3 has been developed for monthly administration to treat postmenopausal osteoporosis.OBJECTIVESThe main objective of the present study was to compare the pharmacokinetics of vitamin D3 administered in 2 forms: a newly developed ibandronate 150-mg/vitamin D3 24,000-IU tablet (DP-R206, test drug) and a stand-alone vitamin D3 24,000-IU tablet (reference drug). A secondary objective was to evaluate the safety and tolerability of DP-R206 in healthy adult male Korean volunteers.METHODSThis study was a single-dose, open-label, randomized-sequence, 2-treatment, 2-way crossover trial. Blood samples were collected from 24 hours' predose to 120 hours' postdose. The plasma concentrations of vitamin D3 were analyzed by using a validated HPLC-MS/MS method. Pharmacokinetic parameters were calculated, and the 90% CIs of the ratios of the geometric means of the parameters were determined from the logarithmically transformed data by using ANOVA.RESULTSThirty-sex healthy adult male Korean volunteers with a mean (SD) age of 25.8 (2.7) years, a mean height of 174.0 (5.9) cm, and a mean weight of 69.1 (6.2) kg were enrolled; 29 participants completed the study. The 90% CIs of the ratios of the geometric means (test drug/reference drug) of the baseline-corrected Cmax, AUC0-last, and AUC0-∞ values were 0.93 to 1.24, 0.89 to 1.19, and 0.87 to 1.18, respectively. The 90% CIs of the ratios of the geometric means (test drug/reference drug) of the baseline-uncorrected Cmax, AUC0-last, and AUC0-∞ values were 0.93 to 1.24, 0.88 to 1.19, and 0.87 to 1.18, respectively. Eighty-four adverse events (AEs) were reported in 24 of 32 subjects receiving DP-R206, and 14 AEs were reported in 8 of 29 subjects receiving the vitamin D3 24,000-IU tablet. All of the subjects who experienced AEs recovered without sequelae, and no serious AEs were observed.CONCLUSIONSThe vitamin D3 pharmacokinetics were similar for DP-R206 and the 24,000-IU vitamin D3 tablet. DP-R206 was well tolerated.
