Table 2.

Population pharmacokinetic parameter estimates for oseltamivir and oseltamivir carboxylate following oral dosing of oseltamivir to patients receiving automated peritoneal dialysis

Kinetic model	Parameter	Description of parameter	Units	Mean estimate	BSV (CV%)
Absorption	Fmet	Fractional conversion to metabolite via first pass	–	0.964	16.9
	kaOP	Rate constant for oseltamivir absorption	1 h−1	1.36	147
	AlagOP	Lag time in absorption of oseltamivir	h	0.485	53.8
	kaOC	Rate constant for oseltamivir carboxylate absorption	1 h−1	0.109	–
Oseltamivir disposition	CLpm	Clearance of oseltamivir to metabolite in plasma	l h−1 (70 kg)−1	9.63	–
	VcOP	Central distribution volume of oseltamivir	l (70 kg)−1	16.7	31.1
	CLD	Intercompartmental clearance of oseltamivir	l h−1 (70 kg)−1	6.80	–
	VpOP	Peripheral distribution volume of oseltamivir	l (70 kg)−1	307	–
Oseltamivir carboxylate disposition	VcOC	Central distribution volume of oseltamivir carboxylate	l (70 kg)−1	32.8 FIX*	38.7
	CLOCCCPD	Clearance of oseltamivir carboxylate by CCPD regimen	l h−1 (70 kg)−1	0.319	7.70
	CLOCCAPD	Clearance of oseltamivir carboxylate by CAPD regimen	l h−1 (70 kg)−1	0.170	7.70
	CLOCURINE	Clearance of oseltamivir carboxylate by renal elimination	l h−1 (70 kg)−1	0.736	117
	CLOCOTH	Clearance of oseltamivir carboxylate by other routes	l h−1 (70 kg)−1	0.319	36.9
Residual error†	CVOP_plasma	Proportional error for oseltamivir in plasma	CV%	–	35.9
	SDOC_plasma	Additive error for oseltamivir carboxylate in plasma	μg l−1	–	73.1
	CVOC_dial	Proportional error for oseltamivir carboxylate in dialysate	CV%	–	14.0
	SDOC_dial	Additive error for oseltamivir carboxylate in dialysate	μg	–	11.6
	CVOC_urine	Proportional error for oseltamivir carboxylate in urine	CV%	–	35.5

Abbreviations are as follows: BSV, between-subject variability; CAPD, continuous ambulatory peritoneal dialysis; CCPD, continuous cycler-assisted peritoneal dialysis; CV, coefficient of variation.

^*Central compartment volume of distribution was fixed to that previously established to avoid parameter identifiability (see Methods).

^†Data were modelled with units of concentration (in micrograms per litre) for plasma and units of amount (in micrograms) for dialysate and urine.