Bioequivalence and Bioavailability Forum

Metadate CD sampling: 24 hours [Design Issues]

posted by Helmut  – Vienna, Austria, 2012-04-13 02:43 (5192 d 04:40 ago) – Posting: # 8419
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Hi John,

I forgot: Pentikis et al. (2002) sampled also for 24 hours; the mean AUC_t/AUC_∞-ratio was 91.4%. I guess that their LLOQ of 250 pg/mL was insufficient to measure concentrations at 24 hours in many subjects. For a 20 mg dose you should aim at an LLOQ of ~50–100 pg/mL. CVs were 9.92% (C_max), 6.48% (AUC_t), and 5.79% (AUC_∞). All studies on MR MPH I know of sampled for 24 hours – some studies on IR MPH only 16 hours.

I don’t have the slightest idea why some people* performed studies of a drug with so little intra-subject variability in 36 subjects (even CV of AUC_0-4 was only 13.5%).
Power for CV 15% and T/R 95% is 83% in just 12 subjects.

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• González MA, Pentikis HS, Anderl N, Benedict MF, DeCory HH, Hirshey Dirksen SJ and SJ Hatch
  Methylphenidate bioavailability from two extended-release formulations
  Int J Clin Pharmacol Ther 40(4), 175–84 (2002)

—
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Helmut Schütz


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Complete thread:

• Metadate CD sampling jag009 2012-04-12 18:11 [Design Issues] 
  • Metadate CD sampling: 24 hours Helmut 2012-04-12 18:45
    • Metadate CD sampling: 24 hours jag009 2012-04-12 23:44
      • Metadate CD sampling: 24 hoursHelmut 2012-04-13 00:43
        • Metadate CD sampling: 24 hours jag009 2012-04-13 15:59
          • power… Helmut 2012-04-13 16:17
          • Sounds fine ElMaestro 2012-04-13 16:35
        • Metadate CD sampling: 24 hours jag009 2012-04-18 15:57
          • Metadate CD sampling: 24 hours ElMaestro 2012-04-18 16:35
            • Metadate CD sampling: 24 hours jag009 2012-04-18 17:09