title: On the modulating effects of temperature, albumin, pH and calcium on the free fractions of phenobarbitone and phenytoin.
abstract: The effects of temperature, albumin, pH and Ca2+ on the binding of phenobarbitone and phenytoin to human serum albumin in buffer have been investigated using equilibrium dialysis. The free fractions of both anticonvulsants were much increased by raising the temperature. Lower free fractions were observed by increasing the albumin concentration from 5-8 g litre-1 and by raising pH from 6 to 9. No significant effect on the free fractions was observed by changing (at pH 7.4) the Ca2+ concentration from 0 to 5 mM. The observed differences in free fractions at 37 degrees C, as determined in phosphate, borate and Krebs-Ringer buffer at pH 7.4, indicate that great care is needed in the choice of dialysis fluid for dialysis of clinical samples.
mesh_terms: D002118:Calcium / Q000097:blood; D003956:Dialysis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010634:Phenobarbital / Q000097:blood*; D010672:Phenytoin / Q000097:blood*; D012709:Serum Albumin / Q000378:metabolism; D013696:Temperature
chemical_list: D012709:Serum Albumin; D010672:Phenytoin; D002118:Calcium; D010634:Phenobarbital