Maybe a simple question? [PK / PD]
Hi all,
Can someone explain to me the following (or a kick in the butt if this is too simple?) from Csizmadia & Endrenyi? I don't have the Gibaldi PK book on hand (they referenced it from his book).
Basis of the Proposed Methods. If a drug exhibits first-order absorption with one-exponential disposition and the absorption (ka) and elimination (k) rate constants are equal, then the plasma concentration (C) depends on time according to:
For the above model,
How did he arrive to
Thanks
John
___________________________________________________________________________
Csizmadia F, Endrenyi L. Model-Independent Estimation of Lag Times with First-Order Absorption and Disposition. J Pharm Sci Vol. 87:5. May 1998
Can someone explain to me the following (or a kick in the butt if this is too simple?) from Csizmadia & Endrenyi? I don't have the Gibaldi PK book on hand (they referenced it from his book).
Basis of the Proposed Methods. If a drug exhibits first-order absorption with one-exponential disposition and the absorption (ka) and elimination (k) rate constants are equal, then the plasma concentration (C) depends on time according to:
C=kAtexp(-kt), where A=FD/V
For the above model,
k=1/Tmax
, where Tmax is the time when the plasma concentration reaches maximum.How did he arrive to
k=1/Tmax
?Thanks
John
___________________________________________________________________________
Csizmadia F, Endrenyi L. Model-Independent Estimation of Lag Times with First-Order Absorption and Disposition. J Pharm Sci Vol. 87:5. May 1998
Complete thread:
- Maybe a simple question?jag009 2013-09-13 15:48 [PK / PD]
- flip-flop PK Helmut 2013-09-13 16:16
- flip-flop PK jag009 2013-09-13 19:51
- flip-flop PK Helmut 2013-09-13 16:16