Related Experiment Video
Updated: Aug 1, 2026
11:56
A Rapid and Specific Microplate Assay for the Determination of Intra- and Extracellular Ascorbate in Cultured Cells
Published on: April 11, 2014
Pharmacokinetic study of ascorbic acid in sheep
1Department of Biomedical Sciences, University of Guelph, Ontario.
Summary
Intramuscular (i.m.) ascorbic acid (AA) administration in sheep resulted in higher plasma concentrations and longer duration compared to intravenous (i.v.) routes. Higher i.m. doses of AA prolonged therapeutic levels more effectively.
Area of Science:
- Veterinary Medicine
- Pharmacokinetics
- Animal Nutrition
Background:
- Ascorbic acid (AA), or Vitamin C, is essential for various physiological processes in animals.
- Understanding the optimal administration route and dosage for AA supplementation in sheep is crucial for animal health and productivity.
Purpose of the Study:
- To compare the pharmacokinetic profiles of ascorbic acid administered intravenously (i.v.) versus intramuscularly (i.m.) in sheep.
- To evaluate the impact of different dosages (1g vs. 3g) on AA plasma levels and duration of action.
Main Methods:
- Four groups of sheep (n=5/group) received AA via i.v. or i.m. routes at 1g or 3g doses.
- Blood samples were collected over 7 hours (i.v.) and 48 hours (i.m.) post-administration.
- Plasma AA concentrations were quantified using High-Performance Liquid Chromatography (HPLC).
Main Results:
- Intravenous AA elimination rate was higher with the 3g dose compared to the 1g dose.
- Area Under the Curve (AUC) for i.v. administration was dose-proportional.
- Intramuscular administration resulted in higher AUC values and longer duration of elevated AA levels compared to i.v. administration, particularly at the 3g dose for levels >10 mcg/mL.
Conclusions:
- Intramuscular administration of ascorbic acid in sheep provides greater and more sustained drug exposure than intravenous administration.
- The i.m. route, especially at higher doses, is more effective for achieving prolonged therapeutic AA levels in sheep.
Related Concept Videos
01:27Bioavailability Study Design: Absolute Versus Relative Bioavailability
Bioavailability is a crucial pharmacokinetic parameter that quantifies the proportion of an administered drug that reaches the systemic circulation and is available for therapeutic action. Regulatory agencies mandate the assessment of bioavailability, typically measured as the area under the drug plasma concentration-versus-time curve (AUC), to ensure the efficacy and safety of pharmaceutical products. These evaluations are categorized as absolute and relative bioavailability studies.Absolute...
01:11Bioavailability Study Design: Single Versus Multiple Dose Studies
Bioavailability studies are essential for understanding how a drug is absorbed, distributed, metabolized, and excreted in the body. These studies assess the extent and rate at which the active pharmaceutical agent becomes available at the site of action. The design of bioavailability studies can involve single-dose or multiple-dose regimens, each with distinct advantages and limitations.Single-dose studies are the preferred approach due to their simplicity and reduced drug exposure for...
01:30Measurement of Bioavailability: Pharmacokinetic Methods
Pharmacokinetics is a vital branch of pharmacology that examines how drugs are absorbed, distributed, metabolized, and excreted by the body. Two key methodologies in pharmacokinetics are plasma drug concentration studies and urinary drug excretion analyses, both of which provide critical insights into a drug's therapeutic efficacy and bioavailability.Plasma Drug Concentration-Time StudiesPlasma drug concentration-time studies involve analyzing blood samples at specific intervals to quantify...
01:20Measurement of Bioavailability: Pharmacodynamic Methods
Pharmacodynamic methods provide insights into a drug's effects on physiological processes over time and play a crucial role in understanding bioavailability and therapeutic efficacy. These methods can be broadly classified into acute pharmacological and therapeutic response approaches, each with distinct mechanisms and applications.The acute pharmacological response method directly correlates a drug's physiological effects, such as ECG or pupil diameter changes, to its time course in the body.
01:01Dosage Regimens: Partial Pharmacokinetic Parameters
It is not uncommon for complete drug pharmacokinetic profiles to remain elusive in pharmacokinetics. This necessitates certain educated assumptions by pharmacokineticists to determine appropriate dosage regimens without comprehensive pharmacokinetic data from animal or human studies. One prevalent assumption is setting the bioavailability factor, denoted as F, to 1 or 100%. This assumption caters to the scenario where a drug doesn't achieve full systemic absorption, resulting in the patient...
01:22Effect of Hepatic Disease on Pharmacokinetics: Pathophysiologic Assessment and Liver Function Test
In clinical practice, the direct measurement of hepatic blood flow to evaluate liver function presents significant challenges due to the intricate and specialized nature of the necessary techniques. Consequently, healthcare professionals often rely on empirical estimates derived from thorough patient examinations and liver function tests to gauge liver health. Among the tools at their disposal, the Child–Pugh and MELD scoring systems stand out for their ability to categorize and assess the...