title: Calorimetric investigation of diclofenac drug binding to a panel of moderately glycated serum albumins.
abstract: Glycation alters the drug binding properties of serum proteins and could affect free drug concentrations in diabetic patients with elevated glycation levels. We investigated the effect of bovine serum albumin glycation by eight physiologically relevant glycation reagents (glucose, ribose, carboxymethyllysine, acetoin, methylglyoxal, glyceraldehyde, diacetyl and glycolaldehyde) on diclofenac drug binding. We used this non-steroidal anti-inflammatory drug diclofenac as a paradigm for acidic drugs with high serum binding and because of its potential cardiovascular risks in diabetic patients. Isothermal titration calorimetry showed that glycation reduced the binding affinity Ka of serum albumin and diclofenac 2 to 6-fold by reducing structural rigidity of albumin. Glycation affected the number of drug binding sites in a glycation reagent dependent manner and lead to a 25% decrease for most reagent, expect for ribose, with decreased by 60% and for the CML-modification, increased the number of binding sites by 60%. Using isothermal titration calorimetry and differential scanning calorimetry we derived the complete thermodynamic characterization of diclofenac binding to all glycated BSA samples. Our results suggest that glycation in diabetic patients could significantly alter the pharmacokinetics of the widely used over-the-counter NSDAI drug diclofenac and with possibly negative implications for patients.
authors.affiliation: Department of Pharmaceutical Sciences, North Dakota State University Fargo, ND, USA.
authors.forename: Venkata S K
authors.initials: VS
authors.lastname: Indurthi
authors.affiliation: Department of Pharmaceutical Sciences, North Dakota State University Fargo, ND, USA.
authors.forename: Estelle
authors.initials: E
authors.lastname: Leclerc
authors.affiliation: Department of Pharmaceutical Sciences, North Dakota State University Fargo, ND, USA.
authors.forename: Stefan W
authors.initials: SW
authors.lastname: Vetter
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry / Q000378:metabolism*; D002151:Calorimetry; D004008:Diclofenac / Q000737:chemistry / Q000378:metabolism*; D017127:Glycation End Products, Advanced; D006031:Glycosylation; D011485:Protein Binding; D011487:Protein Conformation; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism*; D013816:Thermodynamics; D000093423:Glycated Serum Albumin
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D017127:Glycation End Products, Advanced; D012709:Serum Albumin; D004008:Diclofenac; D012710:Serum Albumin, Bovine; D000093423:Glycated Serum Albumin
keywords: Calorimetry; Diabetes; Diclofenac; Drug binding; Protein glycation; Serum albumin