Bioanalytical Methods to Improve Drug Tolerance 1. Acid Dissociation 2. Solid-phase extraction with acid dissociation (SPEAD) 3. Affinity Capture Elution (ACE) 4. Biotin-drug extraction and acid dissociation (BEAD) 5. Precipitation and acid dissociation (PandA) 1. Acid Dissociation methods: Acid-base treatment is a widely adopted dissociation method for improving the drug tolerance of the assay. The method is based on the principle that acid or base breaks any drug: antibody complex interaction thereby allowing the detection/capture reagents to the ADAs. The method involves incubation of ADA: drug complex with weak acid with pH 2-3 (e.g 300mM acetic acid, 0.1 mM Glycine) followed by neutralization with base (1 mM Tris HCl, pH 9.5), whereas if a high concentration of circulating drugs is present, there is a higher probability that ADA re-associates with the drug during the neutralization step. The acid may also negatively affect the assay signal/noise ratio ...