In vitro evaluation of a continuous-sampling device for pharmacokinetic parameter estimation.
Using an in vitro pharmacokinetic model, area under the curve (AUC) estimates from an osmotic continuous-withdrawal device were compared to AUC estimates by a conventional trapezoidal method. Ten experiments were done under two different conditions: (a) half-life of 1 h (n = 5) and (b) half-life of 2 h (n = 5). Sampling was done for 6 and 12 h, respectively. The AUC estimates from the two methods were highly correlated (r = 0.948, p < 0.0001). The mean coefficient of variation was 9.5% (n = 10), and mean AUC values were not statistically different by analysis of variance (p = 0.4). The sampling device sampled at 0.121 +/- 0.011 ml/h; the mean volume was 0.79 +/- 0.03 and 1.34 +/- 0.02 ml over 6 and 12 h, respectively. Continuous sampling provided a reasonable estimation of AUC, required only one analytical sample, and sampled at a consistent zero-order rate.
Paap
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University of Texas at Austin, College of Pharmacy 78712.
Chocas
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D016903:Drug Monitoring / Q000295:instrumentation*; D005069:Evaluation Studies as Topic; D006207:Half-Life; D006801:Humans; D008751:Methylene Blue / Q000032:analysis; D008954:Models, Biological; D010599:Pharmacokinetics; D012044:Regression Analysis; D012984:Software; D013048:Specimen Handling / Q000295:instrumentation
D008751:Methylene Blue