Table 1 Pharmacokinetic parameters^a of capecitabine and its metabolites in plasma, malignant tissue, and healthy connective tissue

Plasma

c_max (μg ml⁻¹)

2.34

6.53

3.65

0.25

(0.64–15.4)

(1.79–8.7)

(1.67–7.22)

(0.09–0.80)

t_max (h)

1.75

1.75

2.0

2.5

(1.0–3.0)

(1.0–3.0)

(1.0–3.0)

(1.0–3.5)

T_1/2 (h)

0.50

0.86

0.80

N.A.

(0.21–0.92)

(0.6–2.33)

(0.44–2.44)

AUC_0−5 h (μg ml⁻¹ h)

2.36

11.3

6.42

0.29

(1.13–17.3)

(4.74–16.5)

(4.26–10.0)

(0.13–1.86)

Tumour

c_max (μg ml⁻¹)

2.66

4.22

2.13

0.26

(0.91–15.7)

(1.54–4.29)

(0.85–4.29)

(0–0.74)

t_max (h)

2.5

2.5

2.5

3.0

(1.5–3.5)

(1.5–3.5)

(1.5–4.0)

(1.0–4.5)

t_1/2 (h)

0.50

0.87

1.08

N.A.

(0.27–1.24)

(0.43–1.59)

(0.48–2.17)

AUC_0−5 h (μg ml¹ h)

3.52

7.89

3.35

0.25

(0.92–33.3)

(2.15–25.2)

(1.43–13.4)

(0–2.28)

s.c. Tissue

c_max (μg ml⁻¹)

2.70

4.37

1.51

0.33

(0.58–28.2)

(1.11–10.1)

(0.70–5.87)

(0.08–1.40)

t_max (h)

2.25

2.5

2.75

2.0

(1.0–3.5)

(1.5–3.5)

(1.5–3.5)

(0.5–3.5)

t_1/2 (h)

0.59

0.76

0.82

N.A.

(0.17–1.5)

(0.57–3.57)

(0.64–2.80)

AUC_0−5 h (μg ml⁻¹ h)

3.16

8.40

2.75

0.36

(0.78–43.5)

(2.31–22.1)

(1.51–11.6)

(0.13–2.21)

Patients received 1250 mg capecitabine m⁻² orally with tap water before collecting plasma samples and interstitial tissue fluid up to 5 h after administration.

^aValues are reported as median and range in parentheses (n=10). DFCR=5′-deoxy-5-fluorocytidine; DFUR=5′-deoxy-5-fluorouridine; FU=5-fluorouracil; cmax=maximum concentration; tmax=time to maximum concentration; t_1/2=elimination half-life; AUC_0−5 h=area under the concentration-time curve from 0 to 5 h; NA=not applicable.