Bioequivalence and Bioavailability Forum

Religious debate [Regulatives / Guidelines]

posted by nobody – 2016-02-12 18:26 (3259 d 19:34 ago) – Posting: # 15986
Views: 19,619

❝ parameterization of models in terms of rate constants or clearances

For models I don't care. I care for the discussions deduced from these parameters. And often the "half-life" discussions are... ehmmm... undercomplex...

❝ What I definitely don’t like is that PK software in evaluating data of an extravascular dose spit out CL/ƒ, V/ƒ, etc. Since ƒ is unknown, this kind of “information” is meaningless

Nope. Sometimes this is as close to "reality" as you can get (if you lack the info on f for example). There are other cases you simply can not get closer to the information you want. Take metabolite pk in the central compartment. In your logic it's all trash, as you will normally not know Vd. And amounts are usually what's interesting (where does the drug go? Sometimes you have urine data, rarely fecal data, and even if, for non-iv application without iv data: how did it end up in feces?), concentrations without Vd normally are of limited value (you can assume Vd metabolite to be smaller than Vd parent, but that doesn't bring you that far, huh?).

There are other cases where you can not obtain all parameters you might want. Deal with it and take as much info out of your data as you can get (on a scientific basis). Better than a lot of (NONMEM) models overparameterized ad nauseam, months of runtime, highly correlated parameters, in the end completely meaningless nonsense. But 6 or 8 compartments, most of them without any meaningful datasets to determine the related parameters...

Complete thread:

• Baseline correction vs non-baseline cor­rection jag009 2015-09-15 20:29 [Regulatives / Guidelines] 
  • Baseline correction vs non-baseline correction Lucas 2015-09-16 14:16
    • Baseline correction vs non-baseline correction Relaxation 2015-09-18 10:25
  • Baseline correction or supra-thera­peu­tic dose Helmut 2015-09-16 15:16
    • Baseline correction or supra-thera­peu­tic dose Ohlbe 2015-09-16 17:55
      • Baseline profile prior to each period? Helmut 2015-09-16 18:15
      • Baseline correction examples Helmut 2015-09-17 15:44
        • Baseline correction examples Lucas 2015-09-18 14:19
          • Baseline correction examples Helmut 2015-09-18 17:28
            • Baseline correction examples Mauricio Sampaio 2016-02-07 03:05
              • Baseline correction examples Lucas 2016-02-10 11:48
                • Postmenopausal women Helmut 2016-02-10 12:26
                • Baseline correction examples Mauricio Sampaio 2016-02-11 01:38
                • Baseline correction examples Dr_Dan 2016-02-11 09:22
                  • Postmenopausal women Mauricio Sampaio 2016-02-12 03:24
                    • Postmenopausal women Dr_Dan 2016-02-15 17:45
            • Baseline correction examples BEQool 2024-11-11 07:34
              • Baseline correction GeoMean and Median mittyri 2024-11-11 11:20
                • Geometric mean? Helmut 2024-11-11 14:53
                  • Geometric mean? BEQool 2024-11-14 08:19
                    • Geometric mean ≈ MLE of median Helmut 2024-11-14 09:54
                      • Geometric mean ≈ MLE of median Mahmoud 2024-11-15 11:26
                        • Bias? Helmut 2024-11-16 08:43
                          • Bias? Mahmoud 2024-11-16 11:12
      • Baseline; another example Helmut 2015-09-18 17:16
        • Baseline; another example nobody 2016-02-12 09:10
          • Baseline; another example Helmut 2016-02-12 13:37
            • Baseline; another example nobody 2016-02-12 14:08
              • Slowly going OT: BE study simulations Helmut 2016-02-12 15:47
                • Slowly going OT: BE study simulations nobody 2016-02-12 16:15
                  • Religious debate Helmut 2016-02-12 17:04
                    • Religious debatenobody 2016-02-12 17:26
                      • Religious debate ElMaestro 2016-02-13 12:53
                        • Religious debate nobody 2016-02-14 15:23
                • Slowly going OT: BE study simulations Ohlbe 2016-02-13 13:10
                  • Slowly going OT: BE study simulations Helmut 2016-02-13 15:02
                    • Slowly going OT: BE study simulations lizhao 2016-02-25 17:31
                      • Business as usual Helmut 2016-02-25 17:44
                        • Business as usual lizhao 2016-02-25 17:59