Question

effect of temperature on binding of drugs to protein

Answer 1

Significant differences were observed in serum concentrations of unbound phenytoin at the two temperatures (P < 0˙05). The mean association constant (K) of phenytoin to serum proteins is 0·016 L/μmol at 25 ± 3 °C and 0˙009 L/μmol at 37 °C, while mean total concentration of binding sites (n(Pt)) seems to be similar between the two temperatures (682 μmol/L for 25 ± 3 °C and 746 μmol/L for 37 °C). Significant differences were observed in binding characteristics of phenytoin to serum proteins for the different temperature conditions of ultrafiltration (P < 0˙05).

Conclusion: Our study confirms that binding affinity for phenytoin–serum protein interaction is approximately 44% lower at 37 °C than at 25 ± 3 °C and consequently, binding potential (K·n(Pt)) is approximately 38% lower at 37 °C than at 25 ± 3 °C.