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Scheme for oral two-compartment pharmacokinetic model

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Differential Equation for Drug Amount in the Body after

Oral Administration

Integrated Equation for Drug Amount in the Body after

Oral Administration

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Semi-Log Plot Showing Pronounced Distribution

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Semi-Log Plot Without Distribution Phase Evident

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Average Plasma Concentration

The average plasma concentration equation can also be

used to calculate appropriate dosing regimens.

For example, if an average plasma concentration of 20mg/L is required and V1 = 15 L, kel = 0.15 hr-1, F = 0.9and a dosing interval of 12 hours, calculate the requireddose!

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C = Ne-kat + Le-t + Me-t

>> & ka >> Ne-kat + Le-t approach zero

C = Me-t ln C = ln M -t

Cr1 = Ne-kat + Le-t ka > Ne-kat : zero

Cr1 = Le-t ln Cr1 = ln L -t

Cr2 = Ne-kat ln Cr2 = ln N - kat

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k21 = Lka + Mka + N

L(ka-) + M(ka-)

kel = /k21

k12 = + - k21 - kel