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Use of partial AUC (PAUC) to evaluate bioequivalence--a case study with complex absorption: methylphenidate.
Jeanne Fourie Zirkelbach1, Andre J Jackson, Yaning Wang
1Office of Clinical Pharmacology, Office of Translational Science, Center for Drug Evaluation & Research Food & Drug Administration, 10903 New Hampshire Ave, Silver Spring, Maryland 20993, USA.
Pharmaceutical Research
|September 26, 2012
Summary
Bioequivalence assessment for methylphenidate modified-release products requires careful consideration. Partial area under the curve (PAUC) sensitivity to absorption changes is product-specific, indicating a need for tailored metrics.
Area of Science:
- Pharmacokinetics and Drug Metabolism
- Pharmaceutical Sciences
- Clinical Pharmacology
Background:
- Methylphenidate modified-release formulations are crucial for managing attention deficit hyperactivity disorder (ADHD) by providing sustained drug delivery.
- Standard bioequivalence (BE) criteria are insufficient for modified-release products due to complex drug release profiles.
- Assessing the performance of partial area under the drug concentration-time curve (PAUC), Cmax, and AUCINF is vital for ensuring therapeutic equivalence.
Purpose of the Study:
- To evaluate the performance of PAUC, Cmax, and AUCINF in assessing bioequivalence for two methylphenidate modified-release products.
- To determine the suitability of standard bioequivalence criteria for modified-release formulations.
Main Methods:
- A two-stage analysis was conducted on plasma concentration data from two methylphenidate modified-release products.
- Simulations were performed to assess the impact of absorption rate constant (K0Fast) and fraction available (F1) on curve shape and BE metrics.
- The sensitivity of PAUC, Cmax, and AUCINF to changes in pharmacokinetic parameters was analyzed.
Main Results:
- The sensitivity of PAUC ratios to changes in K0Fast was found to be product-dependent.
- Product 1 demonstrated greater responsiveness in PAUC0-4h ratios to variations in K0Fast compared to Product 2.
- Product 2 exhibited differential responses in PAUC0-4h ratios based on whether K0Fast increased or decreased.
Conclusions:
- PAUC-estimated drug release profiles are sensitive to absorption changes and exhibit product-specific characteristics.
- A universal PAUC metric may not be suitable for all modified-release methylphenidate products.
- Development of non-product-specific metrics for assessing drug release profiles is warranted.
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