Species | Age | Acyl Glucuronidation | Sulfoxidation | 21-Hydroxylation | Methyl-Hydroxylation | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
M1 | M2a | M2b | M5a | M5b | M6a/b | |||||||||
KM | Vmax | k | KM | Vmax | KM | Vmax | KM | Vmax | KM | Vmax | KM | Vmax | ||
μM | pmol/min/mg | μl/min/mg | μM | pmol/min/mg | μM | pmol/min/mg | μM | pmol/min/mg | μM | pmol/min/mg | μM | pmol/min/mg | ||
Adult | 52 | 18.4 | 101 | 0.228 | 195 | 55.0 | 292 | 71.9 | 293 | 9.76 | 131 | 17.4 | 29.7 | 12.9 |
±7 | ±4.6 | ±48 | ±0.040 | ±97 | ±15.3 | ±244 | ±12.1 | ±40 | ±5.39 | ±27 | ±8.8 | ±17.0 | ±1.5 | |
Pediatric | 9 | 24.2 | 188 | 0.348 | 340 | 52.6 | 347 | 91.7 | 340 | 4.30 | 146 | 8.98 | 84.5 | 11.7 |
±3 | ±4.3 | ±55 | ±0.118 | ±184 | ±5.7 | ±198 | ±42.8 | ±164 | ±2.36 | ±38 | ±5.00 | ±38.7 | ±2.2 |
↵1-a Separate incubations were conducted to measure acyl glucuronidation (M1 formation) and oxidations (M2, M5, and M6 formations) (seeMaterials and Methods). Data represent the average ± SD of results obtained from three individual subjects. Acyl glucuronidation and oxidations of montelukast analyzed by the following eqs. 1 and 2, respectively. Equation 1 Equation 2where ν, S, and k represent metabolic velocity, montelukast concentration, and linear constant to analyze second component observed in the higher substrate concentration, respectively. No statistically significant difference (p > 0.05) was observed in parameters between adult and pediatric subjects.