Equine veterinary journal1984; 16(1); 59-65; doi: 10.1111/j.2042-3306.1984.tb01855.x

Pharmacokinetics of ascorbic acid in horses.

Abstract: The pharmacokinetics of ascorbic acid were studied in 29 horses after intravenous (iv), subcutaneous, intramuscular (im) and oral administration. Following iv injection of 5 and 10 g ascorbic acid, respectively, a biphasic decline of ascorbic acid serum levels was found, indicating that the vitamin distributes in the body according to a two-compartment open model. The apparent volume of distribution (average value for Vd(ss) = 0.6 litre/kg) was approximately equivalent to the volume of total body water. The terminal half-life of the biexponential serum level-time curve (t1/2 beta) varied between 5 and 17 h. Both distribution and elimination were found to be positively correlated with the iv dose administered. Following subcutaneous and im injection, the average bioavailability of ascorbic acid amounted to 82 and 61 per cent, respectively. However, both routes of administration gave rise to marked local irritation. Following oral administration, the systemic availability of ascorbic acid was very poor. Serum levels in most experiments were not increased above the endogenous pre-administration values of the vitamin. Thus, in horses iv injection appears to be the only satisfactory route of administration of ascorbic acid if supplementation is required.
Publication Date: 1984-01-01 PubMed ID: 6714208DOI: 10.1111/j.2042-3306.1984.tb01855.xGoogle Scholar: Lookup
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  • Comparative Study
  • Journal Article


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The research studied how ascorbic acid (vitamin C) behaves in horses’ bodies dependent on different methods of administration: intravenous, subcutaneous, intramuscular, and oral. The findings suggest intravenous injection is the most effective method for vitamin C supplementation in horses, with oral intake being the least effective.

Study Design

  • The research focused on the pharmacokinetics of ascorbic acid in horses, which means it analyzed how the substance was absorbed, distributed, metabolized, and finally, excreted.
  • The experiment was conducted on 29 horses, and the vitamin was administered in four different ways: intravenously (iv), subcutaneously (under the skin), intramuscularly (im), and orally.
  • Different iv doses (5 and 10 g) of ascorbic acid were tested to evaluate the impact of dose variation on the rate of distribution and elimination.


  • After intravenous injection, the decline in levels of ascorbic acid was biphasic, which means it was divided into two distinct phases. This behavior led the researchers to the conclusion that the vitamin distributes throughout the horse’s body according to a two-compartment model.
  • The volume of distribution was comparable to the volume of the horse’s total body water.
  • The half-life of the vitamin – the time in which the concentration of the substance is reduced by half – varied between 5 and 17 hours, depending on the dosage used.
  • The distribution and elimination processes of the vitamin were directly related to the dosage – higher doses resulted in longer distribution and elimination times.

Administration Routes

  • When vitamin C was administered subcutaneously or intramuscularly, its average bioavailability – the portion of the initial drug dose that reaches the systemic circulation and is thus able to exert its therapeutic effect – was 82% and 61%, respectively.
  • However, both these methods caused significant local irritation, making them less suitable for administration.
  • The oral administration of the vitamin was least effective; it failed to increase vitamin C serum levels above the initial values prior to administration.
  • As such, it was concluded that, only intravenous administration proved satisfactory for vitamin C supplementation in horses.

Cite This Article

Lu00f6scher W, Jaeschke G, Keller H. (1984). Pharmacokinetics of ascorbic acid in horses. Equine Vet J, 16(1), 59-65. https://doi.org/10.1111/j.2042-3306.1984.tb01855.x


ISSN: 0425-1644
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 16
Issue: 1
Pages: 59-65

Researcher Affiliations

Lu00f6scher, W
    Jaeschke, G
      Keller, H

        MeSH Terms

        • Absorption
        • Administration, Oral
        • Animals
        • Ascorbic Acid / administration & dosage
        • Ascorbic Acid / blood
        • Ascorbic Acid / metabolism
        • Biological Availability
        • Dogs
        • Guinea Pigs
        • Half-Life
        • Horses / metabolism
        • Humans
        • Injections, Intramuscular
        • Injections, Intravenous
        • Injections, Subcutaneous
        • Kidney / metabolism
        • Kinetics
        • Rats


        This article has been cited 2 times.
        1. Anderson MJ, Ibrahim AS, Cooper BR, Woolcock AD, Moore GE, Taylor SD. Effects of administration of ascorbic acid and low-dose hydrocortisone after infusion of sublethal doses of lipopolysaccharide to horses.. J Vet Intern Med 2020 Nov;34(6):2710-2718.
          doi: 10.1111/jvim.15896pubmed: 33026127google scholar: lookup
        2. Ralston S, Stives M. Supplementation of Ascorbic Acid in Weanling Horses Following Prolonged Transportation.. Animals (Basel) 2012 Apr 16;2(2):184-94.
          doi: 10.3390/ani2020184pubmed: 26486916google scholar: lookup