Polymer sorption of nitroglycerin and stability of molded nitroglycerin tablets in unit-dose packaging

The sorption of nitroglycerin by thermoplastic polymers and the stability of molded nitroglycerin tablets in strip packaging were studied. The polymers investigated varied greatly in their affinity for nitroglycerin, the order of decreasing affinity being: vinyls greater than low density polyethylene greater than ionomers greater than high density polyethylene. With the proper choice of packaging, molded nitroglycerin tablets stabilized with povidone maintained acceptable potency for up to 2 years at 26 degrees when strip packaged in unit doses. Chemical decomposition (hydrolysis) of nitroglycerin also was investigated. Povidone accelerated the decomposition of nitroglycerin; at high temperature, decomposition was a significant factor in tablet stability for tablets containing povidone.