Oxidative Stress and Pharmacokinetics of Pendimethalin in Female Rats

Abstract

The propensity of a dinitroaniline pre-emergence herbicide, pendimethalin, to induce oxidative stress, changes in biochemical parameters, pharmacokinetics, tissue distribution and excretion in serum, kidney, liver and brain of female rats following four oral doses of 109.4 mg/kg b.wt every other day were studied. When rats exposed to pendimethalin, significant increases in tissue malondialdehyde, lactic dehydrogenase and alkaline phosphatase levels (p<0.05) were noticed compared to controls. The activities of catalase in all the tested tissues except brain were significantly increased (p<0.05) after pendimethalin treatment. Pharmacokinetic studies illustrated that when rats were treated with a single dose of 109.4 mg/kg b.wt of pendimethalin, the percentages of pendimethalin excretion in the urine and faeces were 8.72 and 14.31 after 24 which increased to 23.81 and 71.21 after 168 h of administration. The Peak concentrations of pendimethalin were reached at 12 h in serum (3229.14 ng/mL), liver (10162.32 ng/g) and kidneys (1969.17 ng/g), whereas the peak concentration (245.92 ng/g) reached at 24 h after dosing. In all the tested tissues the compound declined in all tissues as time passed after 72 h in serum or after 120 h in liver, kidneys and brain following administration. The disappearance of pendimethalin was found to be biexponentially from the tested tissues with half-life) t½ (of 14.0, 15.0, 2.5, and 29.0 h for the serum, liver, brain and kidneys, respectively. It can be concluded that when female rats are exposed to pendimethalin, it is readily absorbed and subsequently distributed throughout the whole body influencing on the biomarkers oxidative stress and enzyme activities.