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Alex ☆ Austria, 2015-08-25 19:00 (3158 d 09:13 ago) Posting: # 15330 Views: 4,994 |
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Dear all, I am struggling with an apparently simple problem, probably someone can clear my mind. I have PK data following IV and IP administration. Concentrations following IP administration were best described by a zero-order absoprtion model. As AUMC/AUC = MIT ("mean input time") + MRT and for zero-order absorption MIT = absoprtion duration divided by two (=Tabs/2) MRTIP = AUMCIP/AUCIP - Tabs/2 Further, CLIP = F*dose/AUCIP where F is the bioavailability. I can estimate F by AUCIP/AUCIV (same doses were administered) and subsequently CLIP which is equal to CLIV as: CLIP = F*dose/AUCIP = dose/AUCIV = CLIV Does it make sense to calcualte the volume of distribution at steady-state for IP administration by MRTIP*CLIP? Thanks for your efforts, All the best, Alex |
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d_labes ★★★ Berlin, Germany, 2015-08-26 12:47 (3157 d 15:26 ago) @ Alex Posting: # 15334 Views: 3,981 |
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Dear Alex, ❝ I have PK data following IV and IP administration. Concentrations following IP administration were best described by a zero-order absoprtion model. As ❝ ❝ AUMC/AUC = MIT ("mean input time") + MRT IMHO this should read MRTip= AUMC/AUC = MIT + MRTivwith AUMC and AUC from the i.p. data. Then you get with your zero order input MRTiv=MRTip - MIT = MRTip - Tabs/2This should give the same value as MRT obtained from your i.v. data, of course within some random deviations. Together with the clearance CL (obtained from the i.v. data or as you described) you may calculate Vss=CL*MRTivHope this helps. — Regards, Detlew |
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Alex ☆ Austria, 2015-08-26 16:05 (3157 d 12:08 ago) @ d_labes Posting: # 15338 Views: 3,931 |
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Dear Detlew, thanks for your reply! Helps a lot! All the best, Alex |
Ing. Helmut Schütz