Phar 722 Pharmacy Practice III Vitamins- Pantothenic Acid Spring 2006

Pantothenic Acid Study Guide The applicable study guide items in the Vitamin Introduction History Structure The advantages of Pantothenyl Alcohol over Calcium Pantothenate Function of the vitamin Function of Coenzyme A Deficiency condition Commercial forms of the vitamins

History Pantothenic Acid was isolated in the 1930s at the University of Oregon and Oregon State College from yeast and liver. At various times it was known as Vitamin B 3 and B 5.

Chemistry This vitamin can be considered a derivative of β-alanine. It is asymmetric. –The natural form is D(+). –Only the D(+) isomer is active. The reduced alcohol form, pantothenol, is considered as equally active as the parent acid.

Uptake and Metabolism Little is known about the specifics of pantothenic acid and pantothenol uptake. The conversion of the provitamin pantothenol readily occurs. Pantothenic acid is a structural component, but not the active site, of coenzyme A. –This is different from other B vitamins who have direct coenzyme/cofactor roles. The biosynthesis of coenzyme A occurs presumably in the tissues requiring it. –Because coenzyme A is required for nearly all acyl transfers, synthesis would take place in nearly all cells.

Pantothenic Acid Deficiency Pantothenic acid is essential in humans. No specific deficiency symptoms have been described. –Pantothenic acid deficiencies reported in WW II prisoners of war. –The symptoms were of neurological nature.

Hypervitaminosis There have been no reports of toxic doses. There is no UL.

Dosage Forms-1 Nearly all forms use a synthetic, racemic mixture. –This means that double the amount of synthetic vitamin must be used to obtain equivalent active vitamin. –This approach is cheaper than separating the synthetic product into each of the isomers. For stability reasons, pantothenic acid is rarely used in vitamin supplements.

Dosage Forms-2 Calcium Pantothenate –Commonly used in dry dosage forms. –Moderately hygroscopic –Solubility 1 gm/2.8 ml –Unstable for autoclaving Pantothenol (Panthenol) –Reasonably stable –Freely soluble –Used in injectable dosage forms. –Also found in oral dosage forms. Topical Pantothenol Preparations –There is no evidence that this vitamin is effective as a vitamin topically. It apparently has good emollient properties, but these have nothing to do with its systemic role. It is used in shampoos because it leaves the hair “slippery” for combing. The comb slides easily through the hair.

DRIs AI –Infants mg/day –Children ( years)2 - 4 mg/day –Everyone else5 mg/day –Pregnancy6 mg/day –Lactation7 mg/day EAR –None reported RDA –None reported UL –None reported

Food Sources All animal and plant tissues It is assumed we obtain the vitamin from coenzyme A found in the food we eat. Based on cell culture experiments, our intestinal flora may release pantothenic acid. –The fact that prisoners of war have experienced deficiencies of this vitamin indicate that intestinal flora may not be a significant source.