Stability of ranitidine in injectable solutions

Injectable solutions of ranitidine were prepared by dissolving ranitidine hydrochloride in water for injections. The following buffering system has been used: disodium phosphate (anhydrous), potassium dihydrogen phosphate, and phenol as a preservative. Inert gas (nitrogen) was used to displace oxygen from a solution and reduce the possibility of oxidative changes in the formulation. The solution was poured into 2-ml brown-glass ampoules in asceptic condition. Ampoules samples have been stored at three different temperatures. They have been stored at 55 and 40degreesC for 6 months, and at 25degreesC for 12 months. TLC technique has been used for monitoring related substances, and HPLC technique for monitoring phenol and ranitidine content. It has been shown that only those samples that were stored at 25degreesC were actually stable. (C) 2003 Elsevier Science B.V. All rights reserved.