Pharmacokinetic parameters of total radioactivity in plasma and tissues obtained from Fischer 344 rats after a single inhalation exposure to octamethylcyclotetrasiloxane4-a4-b4-c4-d
| Tissue | Sex | tmax | Cmax | AUC0–168 | t1/2 |
|---|---|---|---|---|---|
| h | μg eq/g | μg eq h/g | h | ||
| 7 ppm | |||||
| Plasma | M | 1 | 0.37 + 0.024-e | 8.334-e | 76 |
| F | 0 | 0.31 + 0.034-e | 7.074-e | 58 | |
| Fat | M | 3 | 1.02 + 0.29 | 99.11 | 226 |
| F | 0 | 1.80 + 0.43 | 181.73 | 112 | |
| Liver | M | 0 | 1.20 + 0.11 | 27.12 | 95 |
| F | 0 | 1.45 + 0.10 | 23.36 | 77 | |
| Lung | M | 0 | 1.40 + 0.14 | 78.02 | 121 |
| F | 0 | 1.61 + 0.10 | 86.10 | 122 | |
| Ovary | F | 0 | 1.32 + 0.32 | 26.04 | 68 |
| Uterus | F | 0 | 0.40 + 0.07 | 11.73 | 127 |
| Vagina | F | 1 | 0.75 + 0.28 | 17.28 | 207 |
| Testes | M | 1 | 0.32 + 0.02 | 7.28 | 249 |
| 70 ppm | |||||
| Plasma | M | 1 | 2.96 + 0.144-e | 63.384-e | 55 |
| F | 1 | 2.16 + 0.404-e | 52.814-e | 57 | |
| Fat | M | 24 | 13.88 + 7.78 | 1214.17 | 100 |
| F | 0 | 32.21 + 7.95 | 2218.58 | 81 | |
| Liver | M | 0 | 10.25 + 0.44 | 226.31 | 102 |
| F | 0 | 13.13 + 1.74 | 215.00 | 78 | |
| Lung | M | 0 | 9.37 + 0.49 | 361.90 | 133 |
| F | 0 | 11.00 + 0.94 | 397.55 | 156 | |
| Ovary | F | 0 | 18.77 + 4.99 | 282.88 | 61 |
| Uterus | F | 0 | 3.57 + 0.46 | 125.60 | 129 |
| Vagina | F | 1 | 8.06 + 8.664-f | 243.74 | 49 |
| Testes | M | 1 | 2.78 + 0.19 | 54.90 | 243 |
| 700 ppm | |||||
| Plasma | M | 3 | 17.34 + 0.794-e | 516.954-e | 71 |
| F | 1 | 11.27 + 0.534-e | 474.554-e | 89 | |
| Fat | M | 12 | 151.88 + 17.93 | 16965.79 | 135 |
| F | 3 | 284.21 + 91.68 | 29062.42 | 131 | |
| Liver | M | 0 | 127.45 + 6.32 | 2337.33 | 91 |
| F | 0 | 171.24 + 2.82 | 2312.33 | 111 | |
| Lung | M | 0 | 101.73 + 7.99 | 3081.06 | 143 |
| F | 0 | 95.72 + 12.83 | 2972.31 | 202 | |
| Ovary | F | 0 | 151.41 + 31.58 | 1908.86 | 117 |
| Uterus | F | 0 | 30.27 + 2.43 | 1609.60 | 102 |
| Vagina | F | 0 | 39.97 + 12.55 | 1371.72 | 70 |
| Testes | M | 1 | 26.40 + 1.33 | 573.62 | 328 |
↵4-a The end of the 6-h exposure was designated 0 h.
↵4-b Cmax and tmax were obtained by data inspection (mean values at each sampling time forCmax).
↵4-c AUC was calculated by the trapezoidal rule using SAS Version 6.07 on mean concentration values and target sampling time over 0 h (end of exposure) to 168 h.
↵4-d t1/2 was calculated by regression analysis (SAS Version 6.07) on at least three data points selected by data inspection on the terminal phase of the plasma concentration versus time curve.
↵4-e Units for plasma are micrograms per milliliter (Cmax) and microgram equivalents × hour per milliliter (AUC).
↵4-f Variability may be due to dissection technique.