Objective: A simple suspension method in our previous study indicated that the amount of amlodipine recovered from a Norvasc®OD tablet was decreased by simultaneous suspension of a Magmitt®tablet containing magnesium oxide, due to the increase in pH. However, it is still unclear whether this incompatibility arises in both brand name and generic tablets because the tablets may have different additives and mechanical properties. In this study, we evaluated the degree of incompatibility between Magmitt®tablets and a range of amlodipine besylate tablets, including original and generic versions.
Methods: Twenty-four kinds of amlodipine besylate tablets were used. Magmitt®and amlodipine besylate tablets were suspended in warm water (55°C), and 10 min or 2 h later, the amount of amlodipine in the suspension was measured by HPLC-UV.
Results: For almost all tested tablets, the recovery amount of amlodipine was significantly decreased in the presence of Magmitt®, and the amount recovered varied significantly between the types of amlodipine tablets. However, Magmitt®tablet had little effect on the recovery of amlodipine from two specific brand tablets.
Conclusions: An incompatibility between Magmitt®and most types of amlodipine besylate could be observed, although the degree of incompatibility depended on the brand of amlodipine. These results are useful for the proper use of drugs.
