GLIBENCLAMIDE AND TOLBUTAMIDE IN HUMAN SERUM - RAPID MEASUREMENT OF THE FREE FRACTION

A rapid and reproducible procedure to evaluate the glibenclamide and tolbutamide free fraction in serum was developed. The ultrafiltration technique was used, employing disposable filter units (Centricon 30, Amicon) with 3O.000 MW cutoff. In order to obtain the maximum filtration recovery (l-01+33) the pretreatment of membranes with 0.1 M sodium hydroxide and biilistilled water rdas necessary. Results on the effect of tiaprofenic acid, an antiinflammatory non steroÍdal agent, on glibenclamide and tolbutamide levels in maturity onset diabetic patients are reported. Neither pharmakokinetic parameters, nor the free fraction of sulphonylureas were significantly changed after tiaprofenic acid treatment, thus excluding the rIsk of pharmacological interactions .