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PharmD clinical pharmacy program Level 3, Semester 2 Biopharmaceutics & Pharmacokinetics (PT608(

Intravenous bolus administration

(One-compartment model)

A drug is administered as an injection of a sterile solution formulation. The

volume and concentration of the administered solution must be known in order to

calculate the administered dose.

For example, five milliliters (5mL) of a 2% w/v solution will contain 100mg

of a drug (dose).

·The following assumptions are made:

➢ One-compartment model, first-order process, and passive diffusion are

operative.

➢ No metabolism takes place (elimination is 100 % via renal excretion).

➢ The drug is being monitored in blood (plasma serum) and urine.
/
➢ The drug is distributed to tissues very rapidly after IV administration.

The integrated equation for a first-order process is applied to the elimination of drug

(mass X) in the body:

ln X = ln Xo – kt

log X = log Xo – kt/2.303

N.B. ln A = 2.3 x log A

Where;

X o: Mass (amount) of unchanged drug in the body at time zero (t=0).

X o: Administered IV bolus dose of the drug.

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