Stability of stabilized nitroglycerin tablets in typical distribution and administration systems

A study was undertaken to determine whether or not the present extreme restrictions on the packaging of nitroglycerin tablets are indeed necessary when dispensing the newer stabilized tablets. Baseline tests were conducted on two molded and two compressed sublingual nitroglycerin tablets to determine weight variation, content uniformity, average potency and friability. Stability tests included: (1) use test designed to simulate patient use from a single bottle of 100 tablets over a one-month period; (2) an open plate study wherein tablets were exposed to the atmosphere for 100 days; (3) strip packaging of tablets using foil-foil or foil-cello systems; (4) placement of tablets in medication cups for a seven-day period; (5) repackaging 30-tablet batches in a variety of common prescription containers. All brands of tablets retained potency during normal use when dispensed and stored in their original containers. However, one brand was superior to all others when placed under stress conditions such as open plate exposure. These tablets also retained labeled potency when exposed in a medication cup for a seven-day period, or when repackaged in either foil-foil or foil-cello strips, or when dispensed in a number of ordinary prescription containers. The study indicated that this brand of nitroglycerin tablets might be handled like any other solid dosage form in hospital distribution systems without endangering patient care. However, exceptions to present packaging restrictions must be cleared with the Food and Drug Administration.