Tolazamide

The polyclonal anti-albumin antibodies (goat, fractionated human antiserum, product A1151), Protein G-Sepharose 4B fast flow (recombinant protein expressed in E. coli), immunoglobulin G (goat, ≥ 95% pure) and HSA (essentially fatty acid free, ≥ 96%) were purchased from Sigma-Aldrich (St. Louis, MO, USA). The racemic warfarin (≥ 98%), acetohexamide (99%), gliclazide (≥ 98%), glipizide (˃ 96%), glibenclamide (≥ 99%), and tolbutamide (99.8%) were also acquired from Sigma-Aldrich. The chlorpropamide (≥ 99%) and tolazamide (≥ 99%) were purchased from Santa Cruz Biotechnology (Dallas, TX, USA). The Nucleosil Si-300 and Si-1000 silica (7 μm, particle diameter; pore size, 300 or 1000 Å, respectively) were acquired from Macherey-Nagel (Duren, Germany). All buffers and aqueous solutions were prepared using water from a Milli-Q Advantage 10 A Water system and were filtered using 0.2 μm nylon membranes (EMD Millipore Corporation, Billerica, MA, USA).

The HSA (lyophilized powder, essentially fatty acid free, ≥ 96% pure), L-tryptophan (≥ 98%), R-warfarin (≥ 97% pure), D- (+)-glucose (99.5%), and sodium azide (>95%) were purchased from Sigma Aldrich (St. Louis, MO, USA). The tolazamide (≥ 99% pure) was from Santa Cruz Biotechnology (Dallas, TX, USA). Modification levels of the in vitro glycated HSA samples were measured using a fructosamine kit purchased from Diazyme Laboratories (San Diego, CA, USA), and the protein content of each chromatographic support was measured using a bicinchoninic acid assay (BCA) from Pierce (Rockford, IL, USA). All aqueous solutions were prepared using purified water from a Milli-Q-Advantage A 10 system (EMD Millipore, Billerica, MA, USA); these solutions were filtrated through 0.20 μm GNWP nylon membranes (Fisher Scientific, Pittsburgh, PA, USA).