In Vitro Protein Binding Studies On Aztreonam : Temperature Effects And Thermodynamics
The effect of temperature on protein binding of aztreonam was investigated at pH 7.4 by equilibrium dialysis method using bovine serum albumin (BSA) with the temperatures ranging between 25Â° and 42Â°. Binding parameters like albumin-bound fraction (b), number of binding sites (n), association (binding) constant (K) and the thermodynamic parameters like standard free energy (DGÂ°), enthalpy (DHÂ°) and entropy (DSÂ°) were computed on an in-house PC using PROBE software developed by the authors. The binding of aztreonam was found to decrease with an increase in temperature, the effect being more pronounced at temperatures above 37Â°. The subsequent factorial analysis on the computed b values, confirmed the effect of temperature on binding to be statistically significant. The magnitude and sign of the thermodynamic parameters indicated the interaction between aztreonam and BSA to be predominantly ionic in nature.