the present invention relates to new stable glutamine derivatives and their use in rehydration therapy a nutrition therapy . the stable glutamine derivatives of the present invention can be prepared by coupling glutamine with one or more additional amino acids to provide oligopeptides , or with glucose , or both , or acylating glutamine with a carboxylic acid having 2 to 6 carbon atoms , to provide a compound which is stable to degradation under acidic environments . while any naturally occurring amino acid may be used as the additional amino acid coupled to the glutamine , it is preferred to use alanine or glutamine , alone or in combination as the additional amino acids . a preferred number of total amino acid groups present in the compounds used in the present method ranges from 2 to 5 ( formed from coupling from 1 to 4 amino acids with glutamine ), with dipeptides and tripeptides most preferred . most preferred compounds include alanyl - glutamine , alanyl - glutaminyl glutamine and gamma - glutamyl glutamine . the compounds used in the present invention are known and can be prepared using conventional peptide coupling reactions , such as on a solid phase peptide synthesizer or using 1 , 3 - diisopropyl - carbodiimide ( dipcdi ) activation in solution coupling , as described in hudson , j . org . chem ., 53 ( 3 ): 617 - 624 ( 1988 ) and bodansky et al , synthesis , pp . 453 - 463 ( 1991 ). the compounds of the present invention have been shown to be much stabler in acidic water solutions ( such as they would be expected to face in a patient &# 39 ; s stomach or intestine ) and to drive salt absorption comparable to if not better than glucose ( see fig1 ). fig2 shows the ph dependent degradation of glutamine under acidic conditions . by contrast , the acyl or alanyl derivatives of glutamine of the present invention were degraded & lt ; 10 % even at ph = 1 over 360 hours at room temperature . since the ability to drive the intestinal sodium cotransport mechanism is known to directly correlate to efficacy in treatment of dehydration , especially when associated with diarrhea , these compounds provide an exciting approach to oral rehydration and nutrition therapy . these compounds are useful not only in malnourished children with diarrhea , but also in patients kept too long on parenteral ( iv ) fluids or tube feedings or in those with damaged intestinal mucosa from infection or chemotherapy . the present glutamine derivatives effectively block the degradation of glutamine in the highly acidic conditions which are encountered in the human stomach . in order to perform effectively in oral therapy , the compounds must be able to survive the conditions in the digestive tract while maintaining the ability to stimulate their absorption and maintain the integrity of the intestinal mucosa . the glutamine derivatives of the present invention have been found to provide the requisite acid stability . additionally , these glutamine derivatives provide intestinal sodium cotransport which is comparable to or higher than the use of glutamine itself . the glutamine derivatives of the present invention can be administered either orally or intravenously . when administered orally , the compounds can be administered as a liquid solution , powder , tablet , capsule or lozenge . the compounds can be used in combination with one or more conventional pharmaceutical additive or excipients used in the preparation of tablets , capsules , lozenges and other orally administrable forms . when administered as an intravenous solution , the derivatives of the present invention can be admixed with conventional iv solutions containing various amino acids and nutrients , such as conventional parenteral therapy solutions . such iv solutions are known in the art and used in rehydration and nutrition therapy . the compounds of the present invention are administered at a dose range effective to bring about improved intestinal sodium cotransport . a preferred dosage range of glutamine equivalent ( gln has a molecular weight of 146 ) is 0 . 05 to 0 . 8 g / kg / day of patient body weight , with approximately 0 . 5 to 0 . 6 g / kg / day or solutions of approximately 13 g / l glutamine equivalent ( the solutions have sufficient glutamine derivative to provide an effective glutamine level equivalent to a solution of 13 g / l glutamine ) or 1 - 10 mm glutamine derivatives being most preferred . conventional therapy regimens are followed in oral or intravenous rehydration or nutrition therapy of patients in need thereof . such patients include children who are malnourished and suffer from diarrhea , patients kept too long on iv fluids or tube feeding , or those having damaged intestinal mucosa from infection or chemotherapy . the need for starting treatment in rehydration or nutrition therapy is judged by conventional standards . the therapy is continued until the patient has improved beyond the minimum hydration requirements or as long as the increased nutritional demands require . having generally described this invention , a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified . to study intestinal sodium cotransport using the compounds of the present invention , ala - glu and ala - gln were tested according to the method of lima et al , brazilian j . med biol . res ., 25 : 637 - 640 ( 1992 ) for measuring intestinal sodium cotransport in rabbit ileal mucosa mounted in ussing chambers . fig1 shows the response in intestinal sodium cotransport using ala - gln and ala - glu in rabbit ileal mucosa . as shown the dose response increases dramatically in a non - linear fashion . ala - gln showed a maximum increase ( e max ) in isc of 150 μa / cm 2 , with a pd 2 of 3 . 8 . the pd 2 value is related to the ed 50 in accordance with the following formula : meanwhile , ala - glu showed an e max = 120 μa / cm 2 , with a pd 2 of 4 . 1 . thus , the ala - gln compound of the present invention was found to provide comparable or improved intestinal sodium cotransport compared to ala - glu . obviously , numerous modifications and variations of the present invention are possible in light of the above teachings . it is therefore to be understood that within the scope of the appended claims , the invention may be practiced otherwise than as specifically described herein .
a method for the treatment of dehydration or nitrogen deficiency - based malnutrition is provided which involves administering to a patient in need thereof an effective amount of a compound selected from oligopeptides formed from the coupling of one or more amino acids with glutamine , the product of coupling glucose with glutamine , the product of coupling glucose and one or more amino acids with glutamine , or the product from acylating glutamine with a carboxylic acid having from 2 to 6 carbon atoms .