• Bioequivalence (BE) testing plays an important role in the development and approval of generic drugs and is usually assessed by measuring the rate and extent to which the drug product is absorbed into the blood stream.
• The current BE approach is not applicable for locally acting gastro intestinal (GI) binding drugs such as Colesevelam HCl, Cholestyramine, Sevelamer carbonate, Sevelamer HCl, Lanthanum carbonate, Ferric citrate, Sucroferric oxyhydroxide, Ferric oxyhydroxide., Sucralfate, Patiromer sorbitex calcium and Sodium Zirconium Cyclosilicat etc. since they are not intended to be absorbed into the systemic circulation.
• The drug concentration needs to be estimated at the local GI tract site. These drugs dissociate in the acid environment of the upper GI tract to release ionic drug species that bind to Adsorbate (Phosphate, Bile acid salt, & Potassium etc.) to form an insoluble complex that is eliminated via faeces.

US FDA developed the product specific guidance for In-Vitro BE Studies i.e.

• Equilibrium Binding studies at different pH, minimum eight concentration levels and fixed incubation time for the evaluation of Langmuir binding constant (k1), capacity constant (k2) and conclusion of BE studies (90% confidence intervals).
• Kinetic Binding studies at different pH, three concentrations levels and minimum eight time intervals for evaluation and comparison of Test/Reference bound ratio at various time intervals.

DALPL, having experienced team in In-Vitro binding studies, method validation and method development, provides complete product development services utilizing in-vitro bioequivalence (Equilibrium binding studies and Kinetic binding studies) models and other scientific tools.

We have developed method for Colesevelam HCl, Cholestyramine, Sevelamer carbonate, Sevelamer HCl, Lanthanum carbonate, Ferric citrate, Ferric oxyhydroxide, Sucralfate, Patiromer sorbitex calcium and Sodium Zirconium Cyclosilicat etc.