Coordination polymers as potential solid forms of drugs: three zinc(II) coordination polymers of theophylline with biocompatible organic acids

The biocompatible organic acids such as acetic acid (Hac), benzoic acid (Hbz) and nicotinic acid (Hnit), have been employed as second ligands to assemble biocompatible coordination polymers of theophylline (Hthp), respectively. As a result, three coordination polymers [Zn-2(thp)(2)(ac)(OH)](n) (1), [Zn-2(thp)(2)(bz)(OH)](n) (2) and [Zn(thp)(nit)](infinity) (3) have been synthesized through hydrothermal and mechanochemical reactions. Theophylline could be released rapidly in simulated gastroenteric fluid (phosphate-buffered solution, PBS) and slow release of theophylline could be achieved from the three polymers in pure water at 37 degrees C with continuous stirring.