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Biowaiver or Bioequivalence: Ambiguity in Sildenafil Citrate BCS Classification
Claudia Miranda1, Zenia Pérez-Rodríguez1, Rosario Hernández-Armengol1
1Unit of Modeling and Experimental Biopharmaceutics, Centre of Chemical Bioactive, Central University of Las Villas, 54830, Santa Clara, Villa Clara, Cuba.
AAPS Pharmscitech
|March 14, 2018
Summary
Sildenafil citrate exhibits pH-dependent solubility and high intestinal permeability. These characteristics classify it as a Biopharmaceutics Classification System (BCS) Class II drug, impacting its formulation and biowaiver potential.
Area of Science:
- Pharmacokinetics and Drug Development
- Biopharmaceutics and Drug Classification
Background:
- The Biopharmaceutics Classification System (BCS) aids in predicting drug absorption and facilitates biowaiver applications.
- Sildenafil citrate's BCS classification is crucial for regulatory purposes and formulation strategies.
Purpose of the Study:
- To scientifically characterize sildenafil citrate's solubility and intestinal permeability.
- To determine the BCS class of sildenafil citrate following World Health Organization (WHO) biowaiver guidelines.
Main Methods:
- Determined pH-solubility profile using the saturation shake-flask method (pH 1.2-6.8, 37°C).
- Assessed intestinal permeability in rats via an in situ closed-loop perfusion (Doluisio technique).
- Collected and analyzed existing literature data on solubility and permeability.
Main Results:
- Sildenafil citrate solubility is pH-dependent, failing WHO criteria for "high solubility" at pH 6.8.
- In situ intestinal perfusion confirmed high permeability, consistent with literature data.
- Dose/solubility ratio at pH 6.8 indicated it does not meet "high solubility" criteria.
Conclusions:
- Sildenafil citrate demonstrates pH-dependent solubility and high intestinal permeability.
- Based on experimental data and literature, sildenafil citrate is classified as BCS Class II.
- This classification aligns with WHO guidance for biopharmaceutics and drug characterization.
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