The stability of L-glutamine in total parenteral nutrition solutions

An assessment was made over a period of 14 days of the rate of glutamine degradation in different intravenous solutions kept at 22-24 degrees C, 4 degrees C, -20 degrees C and -80 degrees C. At room temperature (22-24 degrees C) degradation rates in mixed parenteral nutrition solutions and aminoacid/dextrose solutions ranged from 0.7-0.9%/day, in Perifusin 0.6%/day, and in dextrose alone as low as 0.15%/day. At 4 degrees C, glutamine degradation was <0.1-0.2%/day in all solutions examined, at -20 degrees C it was minimal (<0.04%/day) and at -80 degrees C, it was undetectable. Glutamine degradation was found to be associated with the formation of equimolar quantities of ammonia. No glutamate formation was detected. It is concluded that it is possible to store glutamine in parenteral nutrition solutions kept at 4 degrees C, with about 2% loss over a period of 14 days. The degradation is sufficiently slow to consider the use of intravenous glutamine in nutritional therapy.