Pharmacokinetics and haematological parameters of recombinant human erythropoietin after subcutaneous administrations in horses.

The research investigates how the drug, recombinant human erythropoietin (rHuEpo), interacts with the bodies of horses after being administered subcutaneously. Findings showed some changes in red blood cells, haemoglobin, and hematocrit after multiple and high doses.

Research Methodology

• The study involved pharmacokinetic analysis of the drug, rHuEpo, on horses. Pharmacokinetics is a branch of pharmacology dedicated to determining the fate of substances administered externally to a living organism.
• Four horses were administered a single dose of 30IU kg-1 of rHuEpo. One horse received a triple dose of 120 IU kg-1 every 48 hours. The difference in dosage allowed for a comparative analysis of the effects of the drug.
• Erythropoietin (Epo), a hormone produced by the kidney to promote the formation of red blood cells by the bone marrow, was measured in plasma using radioimmunoassay, which is a method to measure concentrations of antigens.
• The research applied a one-compartment open model to evaluate the pharmacokinetic parameters. This model assumes that the body is a single, homogeneously perfused compartment in terms of drug distribution. Input and output of the drug were assumed to follow first-order kinetics (rate of reaction is directly proportional to the concentration of the unconverted reactants).

Findings

• Parameters measured include elimination half-life (the time it takes for the body to reduce the amount of drug in plasma or total body content by one-half), CL/F (the clearance of the drug from the body when administered via extravascular route), and Vd/F (the total amount of drug in the body divided by the drug concentration in the plasma).
• The values of these parameters varied after a single dose and multiple doses, providing evidence of different pharmacokinetics under different administration circumstances.
• Haematological parameters (related to blood) remained relatively unchanged after a single, low dose administration compared to base values. However, multiple and high doses influenced red blood cells, haemoglobin (transports oxygen in the blood), and haematocrit (proportion of blood volume that is red blood cells).
• The plasma Epo assay proved useful in supporting a positive result up to 72 hours after the last rHuEpo administration. This could be vital in anti-doping control procedures.