Profile of P-glycoprotein distribution in the rat and its possible influence on the salbutamol intestinal absorption process.

The intrinsic absorption of salbutamol in different intestinal segments of the rat was measured and related with the corresponding intestinal P-glycoprotein (P-gp) expression levels. The apparent absorption rate constants (k(a), h(-1)) observed in each fraction by means of the "in situ" rat gut absorption method after perfusion of a 0.29-mM isotonic solution of salbutamol were used as absorption indexes.

Activity-bioavailability balance in oral drug development for a selected group of 6-fluoroquinolones.

A nomogram is proposed to select the best candidate in drug development studies with quinolones and is intended to substitute other possible models. The nomogram is referred to as an activity-bioavailability balance (ABB) because it includes the following two criteria: ABB = [(1/gm MIC drug candidate)/ (1/gm MIC ciprofloxacin)].[(F(calc) drug candidate)/( F(calc) ciproflaxacin)].