Table 4 Pharmacokinetic parameters (geometric mean or median (T_max) and range) for morphine 3-glucuronide following a single administration of codeine (0.3, 0.6 and 1.2 mg/kg oral) or morphine (0.2 mg/kg IV) to adult horses. All values reported were generated using non-compartmental analysis

 M6G

9.55 (6.82–12.8)^c

3.0 (0.75–3.0)

0.102 (0.056–0.158)

6.37 (4.38–12.5)

79.0 (49.3–113.9)

 M3G

199.9 (130.2–320.6)^bc

3.9 (0.75–4.0)

0.104 (0.087–0.154)

6.58 (4.51–7.96)

1782 (1251–2839)^bcd

 C6G

68.6 (32.8–101.9) ^bc

2.0 (0.5–3.0)

0.181 (0.104–0.332)

3.54 (2.09–6.65)

383.6 (263.2–665.6)^bc

 Norcodeine

0.62 (0.37–1.32)^c

0.75 (0.75–1.0)

0.258 (0.152–0.487)^bc

2.44 (1.42–4.55)^bc

2.53 (1.04–6.69)^bc

 M6G

14.0 (17.0–23.3)^c

2.0 (0.5–12.0)

0.092 (0.046–0.122)

7.24 (5.66–14.9)

123.6 (71.3–211.0)^cd

 M3G

370.8 (235.9–760.1)^ac

2.5 (0.5–12.0)

0.094 (0.063–0.120)

7.23 (5.79–11.0)

3540 (2780–4608)^acd

 C6G

129.6 (56.4–254.6) ^ac

2.5 (0.5–12.0)

0.174 (0.120–0.298)

3.76 (2.32–5.77)

729.6 (420.7–1032)^ac

 Norcodeine

0.88 (0.49–1.68)

0.75 (0.5–3.0)^c

0.149 (0.051–0.357)

3.93 (1.94–13.7)^a

5.55 (2.58–13.7)^ac

 M6G

24.4 (14.0–44.3)^abd

1.5 (0.5–12.0)

0.091 (0.055–0.123

7.38 (5.64–12.5)

238.3 (165.0–436.0)^abd

 M3G

579.4 (277.5–1265.3)

2.5 (0.5–12.0)

0.093 (0.079–0.113)

7.42 (6.16–8.73)

6710 (4993–9631)^abd

 C6G

219.4 (90.9–481.0) ^ab

1.4 (0.5–12.0)

0.151 (0.096–0.221)

4.43 (3.14–7.22)

1346 (663.3–2081)^ab

 Norcodeine

1.48 (0.59–7.34)^a

0.5 (0.25–2.0)^b

0.123 (0.026–0.215)^a

4.26 (1.79–27.0)^a

10.8 (3.62–32.1)^ab

 M6G

14.5 (8.17–17.9)

0.16 (0.16–0.25)

0.118 (0.081–0.152)

5.78 (4.56–8.58)

54.5 (38.7–74.1)^bc

 M3G

320.3 (214.2–400.6)

0.16 (0.16–0.75)

0.079 (0.046–0.114)

8.41 (6.07–15.0)

1438 (1130–1706)^abc