A pharmacokinetic interpretation of increasing concentrations of DEHP in haemodialysed patients.

The degree of exposure to DEHP was assessed in 11 patients with chronic renal failure undergoing maintenance haemodialysis. The amount of DEHP leached from the dialyser during a 4-h dialysis session was estimated by monitoring the DEHP blood concentration using a HPLC method. When a patient undergoes a dialysis treatment, the concentration of di-2-ethylhexyl phthalate (DEHP) in venous blood is increased when the blood crosses through the dialysis apparatus.

Concentration at steady-state after periodic and non-uniform administration of drug.

A two-compartment model, with absorption from the gut and elimination from both compartments, is considered in order to express the concentration at any time and at steady-state when a drug is administered repeatedly according to a dosing schedule non-uniformly distributed over a 24-h interval. A time-delay is included to take into account the drug crossing from the gut to the central compartment.

Enterohepatic recirculation of the new antihypertensive drug UP 269-6 in humans. A possible model to account for multiple plasma peaks.

Following a single dose of a new antihypertensive drug, UP 269-6 (5-methyl-7-propyl-8-[(2'-(1H-tetrazol-5-yl) biphenyl-4-yl)methyl]-1,2,4-triazolo[1,5-c]pyrimidin-2(3H)-one, CAS 148504-51-2), to 12 healthy volunteers, the plasma levels showed at least two secondary peaks. To explain this observation, the data were fitted to a new compartmental model of enterohepatic recirculation, without using a numerical method. Most subjects exhibited two cycles of recirculation.