X. PHARMACOLOGY 681 



studied in mice, rats, dogs, and monkeys. The LDbo after subcutaneous 

 injection is 2.7 g. per kilogram in mice and 3.4 g. per kilogram in rats. The 

 LD50 after oral administration in mice is 10 g. per kilogram of body weight, 

 but rats fed the same amount of pantothenic acid survived without showing 

 toxic symptoms. After intraperitoneal and intravenous injections the LD50 

 for mice is 0.92 and 0.91 g. per kilogram, respectively, and for rats it is 0.82 

 and 0.83.^ Lethal doses produced prostration and respiratory failure in rats 

 and mice. No toxic symptoms were observed in five dogs and one monkey 

 fed 1 g. of calcium pantothenate per kilogram of body weight.^ Pantothenic 

 acid is essentially non-toxic to human beings. At least 100 mg. may be in- 

 jected intravenously in man without producing any toxic reactions.^ 



Chronic toxicity was studied in rats, dogs, and monkeys. Daily doses 

 of 50 and 200 mg., respectively, of calcium pantothenate were fed to young 

 male and female rats over a period of 190 days. Growth was normal, and 

 autopsies at the end of the feeding period did not reveal any gross or mi- 

 croscopic changes in the organs. Offsprings of the group of rats receiving 

 50 mg. of calcium pantothenate daily were given this dose of pantothenic 

 acid from the day that they were weaned. These second-generation animals 

 also developed normally.^ 



Adult dogs were fed daily 50 mg. of calcium pantothenate per kilogram, 

 and monkeys 1.0 g. per kilogram over a period of 6 months. Neither the 

 dogs nor the monkeys showed any toxic symptoms or loss of weight. Histo- 

 pathological examination of these animals failed to reveal any changes. ^ 



Local effects of calcium pantothenate were studied on rabbits by subcu- 

 taneous injections and instillation into the conjunctival sac. No irritation, 

 inflammation, or abscess formation was observed following the subcutan- 

 eous injection of 1.0 ml. of 1, 2, 5, and 10% solutions of the vitamin. The 

 infiltration of the subcutaneous tissue subsided about as rapidly as that 

 following an injection of 1.0 ml. of saline solution. Instillation of 0.5 ml. of 

 a 10 % solution into the conjunctival sac did not produce any irritation.^ 



Calcium pantothenate did not influence the metabolism, circulatory and 

 respiratory systems, or the smooth muscle organs of normal animals.^ 



2 T. D. Spies, D. P. Hightower, and L. H. Hubbard, /. Avi. Med. Assoc. 115, 292 



(1940). 

 ^ F. A. Robinson, The Vitamin B Complex. John Wiley and Sons, New York, 1951. 

 * H. Molitor and G. A. Emerson, Vitamins and Hormones 6, 69 (1948). 



