Dissolution testing of nitroglycerin tablets.
The available types of dissolution testing apparatus for tablets and capsules are inapplicable to sublingual tablets, since these tablets are formulated to release their drug content within minutes in a small volume of fluid. A simple dissolution test method was developed for nitroglycerin tablets based on the reduction of nitroglycerin at a rotating platinum electrode, which provides reproducible stirring. The system provides instantaneous and continuous measurement of dissolved nitroglycerin in a small constant volume of buffered isotonic sodium chloride solution over a period of seconds to several minutes, when reduction is complete as shown by the current-time curve. Since the height of the curve is directly proportional to the amount of nitroglycerin in solution, the method also can be used to determine the drug content of individual tablets.