Page 71 - Pharmaceutics III_ 02-06-01304_Fall 2025_ Pharm D_Electronic book
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Class Solubility Permeability Example
IV Low Low Hydrochlorothiazide
BCS and Formulation Design:
• Class I: simple formulation sufficient.
• Class II: dissolution enhancement critical.
• Class III: permeability enhancement important.
• Class IV: complex formulation (nanoparticles, lipids).
Bioavailability Testing:
Measured by plasma concentration–time curve (Cmax, Tmax, AUC).
Bioequivalence:
Two formulations considered bioequivalent if 90% CI of AUC and Cmax within 80–125%.
In Vitro–In Vivo Correlation (IVIVC):
Mathematical relationship between in vitro dissolution and in vivo absorption.
Levels:
• Level A (point-to-point, best).
• Level B (statistical).
• Level C (single parameter correlation).
Factors Affecting Tablet Bioavailability:
• Drug solubility and particle size.
• Disintegration and dissolution rate.
• Excipient interactions.
• Coating and formulation type.
• Gastric emptying rate.
Enhancement of Tablet Bioavailability:
• Use of surfactants and solubilizers.
• Particle size reduction.
• Use of amorphous form.
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