ALLANTOIN AND UREA— ROBINSON 455 



any harmful effect being found. A few published reports of results 

 are beginning to appear in the medical Uterature (Greenbaum, 1936; 

 Kaplan, 1937; Nicholl, 1937; Rice, 1936; Sussman, 1937). 



The publicity that was given so frequently by the press to the 

 discovery of the healing properties of allantoin interested not only the 

 medical profession and the laity in its use but also a number of chemi- 

 cal and pharmaceutical concerns in its production. Within a few 

 months allantoin was offered to the medical profession in crystalline 

 form, in solution, in ointment, and in surgical jelly preparations, and 

 it is now being sold in tablet form with okra for the treatment of 

 stomach ulcers. In the ointment and jelly preparations allantoin 

 must be dissolved and concentrated in hot water and then incor- 

 porated with the other materials which make up the base. Green- 

 baum (1936) describes the process in detail. An ointment made 

 merely by adding pulverized allantoin crystals to an ointment base 

 already prepared was once placed on the market for a short time. 

 Such mixtures are ineffective, especially when a greasy base is used, 

 because of the insolubility of allantoin except in hot water. Through 

 the enterprise of pharmaceutical industries there is now no difficulty 

 in obtaining allantoin products in any part of the United States. 

 Over 80 allantoin preparations have been advertised for medical use. 



The amount of allantoin being used medicinally in its various prepa- 

 rations is rather surprising. According to authentic sales reports, 

 about 300,000 grams of synthetic allantoin crystals are now being 

 produced annually. This amount would make over 140,000 pints of 

 0.4 percent solution, the usual concentration used clinically, or over 

 500,000 ounces of 2-percent ointment. It remains to be seen whether 

 the popularity of allantoin will continue or whether it will suffer the 

 fate of many other new drugs and eventually fall into disuse. At any 

 rate, the present response to its discovery in maggot secretions is in 

 strong contrast to the reception given to its previous discovery by 

 Macalister in the roots of comfrey. 



The effectiveness of allantoin in stimulating healing, now being 

 established, led to the possibility that other substances with thera- 

 peutic properties might also be found in maggot excretions. The 

 graphic chemical formula for allantoin is: 



NH-CH-NH-C 0-NHj 



I I 

 00 I 



I I 



NH-CO 



The side chain NH-CO-NH2 upon hydrolysis through the addition of 

 H from water easily forms urea, NH2-CO-NH2. Urea is present in 

 maggot excretions and was therefore considered as a possible healing 

 substance. 



