http://en.wikipedia.org/wiki/Pharmacokinetics | :: MTU News ::

Friday, 9 August 2013

http://en.wikipedia.org/wiki/Pharmacokinetics

at 10:36

Posted by Pramod Maurya

Characteristic	Description	Example value	Symbol	Formula
Dose	Amount of drug administered.	500 mg	$D$	Design parameter
Dosing interval	Time between drug dose administrations.	24 h	$\tau$	Design parameter
C_max	The peak plasma concentration of a drug after administration.	60.9 mg/L	$C_\text{max}$	Direct measurement
t_max	Time to reach C_max.	3.9 h	$t_\text{max}$	Direct measurement
C_min	The lowest (trough) concentration that a drug reaches before the next dose is administered.	27.7 mg/L	$C_{\text{min}, \text{ss}}$	Direct measurement
Volume of distribution	The apparent volume in which a drug is distributed (i.e., the parameter relating drug concentration to drug amount in the body).	6.0 L	$V_\text{d}$	$= \frac{D}{C_0}$
Concentration	Amount of drug in a given volume of plasma.	83.3 mg/L	$C_{0}, C_\text{ss}$	$= \frac{D}{V_\text{d}}$
Elimination half-life	The time required for the concentration of the drug to reach half of its original value.	12 h	$t_\frac{1}{2}$	$= \frac{ln(2)}{k_\text{e}}$
Elimination rate constant	The rate at which a drug is removed from the body.	0.0578 h⁻¹	$k_\text{e}$	$= \frac{ln(2)}{t_\frac{1}{2}} = \frac{CL}{V_\text{d}}$
Infusion rate	Rate of infusion required to balance elimination.	50 mg/h	$k_\text{in}$	$= C_\text{ss} \cdot CL$
Area under the curve	The integral of the concentration-time curve (after a single dose or in steady state).	1,320 mg/L·h	$AUC_{0 - \infty}$	$= \int_{0}^{\infty}C\, \operatorname{d}t$
Area under the curve		1,320 mg/L·h	$AUC_{\tau, \text{ss}}$	$= \int_{t}^{t + \tau}C\, \operatorname{d}t$
Clearance	The volume of plasma cleared of the drug per unit time.	0.38 L/h	$CL$	$= V_\text{d} \cdot k_\text{e} = \frac{D}{AUC}$
Bioavailability	The systemically available fraction of a drug.	0.8	$f$	$= \frac{AUC_\text{po} \cdot D_\text{iv}}{AUC_\text{iv} \cdot D_\text{po}}$
Fluctuation	Peak trough fluctuation within one dosing interval at steady state	41.8 %	$%PTF$	$= \frac{C_{\text{max}, \text{ss}} - C_{\text{min}, \text{ss}}}{C_{\text{av}, \text{ss}}} \cdot 100$ where $C_{\text{av},\text{ss}} = \frac{1}{\tau}AUC_{\tau, \text{ss}}$
[ v t e ] http://en.wikipedia.org/wiki/Pharmacokinetics

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