These studies are performed typically on the drug products that containactive ingredients, which do not get systematically absorbed. FDA has suggested & published the guidelines for In-Vitro Binding Studies in place of Clinical BE study.

We have been doing these studies for various products such as Sevelamer HCL Tablets, Sevelamer carbonate, Colesevelam Hydrochloride Tablets, Colesevelam Hydrochloride Capsules, Cholestyramine Powder for Suspension etc.

Following are the most important points for conduct of such study:

1. This study is not a mere Analytical comparison between the test and reference. This shall be considered as substitute to clinical trial
2. The flow of study shall be a) Development trial b) Validation of method for estimation of binding capacity on the lines of Bio analytical Method Validation guidelines c) Pilot trial d) Pivotal Study with first Kineteic binding followed by Equilibrium binding
3. Use of QC level is must to bracket the test and reference dosage units in each set of kinetic and as well as Equilibrium study.
4. Min. twelve replicates of Kinetic and Equilibrium at each variable condition, if not specified in the guidelines.
5. During development we also need to study the binding at extended concentrations of analytes and not to restrict ourselves to those mentioned in the guidelines or innovator’s published litreture.
6. The data shall be presented with Langmuir calculation for binding constants.
7. All activities including dispensing of dosages units and retention samples shall be monitored by QA as done in case of BE study.