In the present study, we examined the effects of light, temperature and humidity on the residual rate of alfacalcidol in four commercially available preparations of alfacalcidol (Alfarol® capsules, Alfarol® powder, Warkmin® capsules and Onealfa® tablets). The tests were performed for up to 10 weeks with PTP seals, or without PTP seals. The changes in residual rate of alfacalcidol in Alfarol® powder packaged with cellophane-laminate paper, and Onealfa® tablets packaged with cellophane-laminate paper after crushing were also examined.
The residual rate of alfacalcidol decreased in Alfarol® capsules packaged with PTP seals under fluorescent lighting (1000 lux) and in Alfarol® powder without an aluminum seal under all conditions. There were no changes in the contents of alfacalcidol in Alfarol® capsules with PTP seals and Alfarol® powder packaged by aluminum seal. A slight decrease in the residual rate of alfacalcidol in Warkmin® capsules was found under fluorescent lighting. The residual rate of alfacalcidol decreased in Onealfa® tablets under high temperature and/or high humidity. Alfarol® powder packaged with cellophane-laminate paper and Onealfa® tablets packaged with cellophane-laminete paper after crushing were found to be unstable, indicating that long-term storage should be avoided when these formulations are prepared.
