Absorption of vitamin K-2 by dogs after oral administration of a soft gelatin capsule formulation containing a new emulsion-type vehicle

This study has evaluated the performance of a newly developed vehicle for a dministration of a drug in a soft gelatin capsule. The absorption of vitami n K-2 in dogs after oral administration of the vitamin in a soft gelatin ca psule containing the newly developed vehicle was compared with absorption a fter administration of a control formulation prepared by encapsulating the contents of a commercially available vitamin K-2 capsule (Glakay capsules 1 5 mg) in the same type of soft gelatin. Under non-fasted conditions the profile of the plasma concentration of vita min K-2 against time for the test formulation was comparable with that for the control formulation in non-fasted dogs. Under fasted conditions, howeve r, both the maximum concentration (C-max) and the area under the plot of co ncentration against lime (AUC) were significantly smaller for the test form ulation than for the control formulation. The C-max and AUC for the test fo rmulation were about 10 times larger for non-fasted dogs than for fasted do gs whereas values for the control formulation were about twice as large. Th ese results suggest that both formulations might require the presence of fo od or digestive fluid components, or both, for better absorption of vitamin K-2 It seems that although the performances of the test and control formul ations were comparable in the presence of these components, the control for mulation works better in their absence. It should be also noted that, in co ntrast with the results from the absorption tests, the dispersibility of th e test vehicle in water was much better than that of the control vehicle. T his suggests that dispersibility does not significantly affect vitamin K-2 absorption. In conclusion, although the new vehicle did not perform better than the con trol vehicle in terms of vitamin K-2 absorption, the performance of the con trol formulation was comparable for non-fasted dogs. Because the new vehicl e contains considerably less surfactant than the vehicles currently used in soft gelatin capsules, it could be a safer alternative for use under non-f asted conditions.