Phar 722 Pharmacy Practice III

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Phar 722Pharmacy Practice III

• Vitamins-
• Pantothenic Acid
• Spring 2006

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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

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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 B3 and
  B5.

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Chemistry

• This vitamin can be considered a derivative of
  ß-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.

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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.

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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.

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Hypervitaminosis

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

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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.

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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.

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DRIs

• AI
• Infants 1.7 - 1.8 mg/day
• Children (1 - 13 years) 2 - 4 mg/day
• Everyone else 5 mg/day
• Pregnancy 6 mg/day
• Lactation 7 mg/day
• EAR
• None reported
• RDA
• None reported
• UL
• None reported

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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.