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Pesticide residues in food — 2007: Toxicological ... - ipcs inchem

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406<br />

The metabolism of r<strong>in</strong>g-labelled [ 14 C]profenofos (specific activity, 26.2 µCi/mg (969 kBq/mg)<br />

was <strong>in</strong>vestigated us<strong>in</strong>g the ur<strong>in</strong>e and faeces collected over a 2-day period after giv<strong>in</strong>g eleven male<br />

RAI rats a s<strong>in</strong>gle oral dose at 28.5 mg/kg bw; 90.4% and 3.6% of the adm<strong>in</strong>istered dose was excreted<br />

<strong>in</strong> ur<strong>in</strong>e and faeces with<strong>in</strong> 24 h. The major metabolites detected were CGA 65867 (7%), CGA 47196<br />

(23%), CGA 55163 (26%) and metabolite C (34%). CGA 47197 was present as a m<strong>in</strong>or metabolite<br />

(< 0.5%). Neither unchanged profenofos nor its correspond<strong>in</strong>g phenol CGA 55960 was detected <strong>in</strong><br />

freshly-obta<strong>in</strong>ed ur<strong>in</strong>e. The faeces conta<strong>in</strong>ed small amounts of parent profenofos (2%), and CGA<br />

55960 (1%). Additional metabolites were present <strong>in</strong> m<strong>in</strong>ute amounts (0.2% or less) but were not<br />

identified (Ifflaender & Mücke, 1976).<br />

A small amount (approximately 7%) of CGA 55960 was found <strong>in</strong> the ur<strong>in</strong>e of male rats<br />

(Tif:RAI-f stra<strong>in</strong>) dosed orally with s<strong>in</strong>gle doses of r<strong>in</strong>g-labelled [ 14 C]profenofos at 0.19 or 1.80 mg/<br />

kg bw. The ma<strong>in</strong> ur<strong>in</strong>ary metabolites identified <strong>in</strong> this study were similar to those reported previously<br />

by Mücke and colleagues (Mücke, 1986).<br />

The pattern of metabolites was <strong>in</strong>vestigated <strong>in</strong> ur<strong>in</strong>e and faeces of groups of five male and<br />

five female Crl:CD®BR rats given [ 14 C]profenofos as a s<strong>in</strong>gle dose at 1 or 100 mg/kg bw, or [ 14 C]<br />

profenofos as a s<strong>in</strong>gle dose at 1 mg/kg bw after 14 consecutive daily oral doses of non-radiolabelled<br />

profenofos at 1 mg/kg bw. The metabolites identified <strong>in</strong> the ur<strong>in</strong>e were metabolite C – the<br />

sulfated phenol (37–48%), CGA 55163 (22–27%), CGA 47196 (14–25%), CGA 65867 (5–16%),<br />

and CGA 55960 (0.1–1.7%). Major faecal components consisted of small amounts of profenofos<br />

(< 0.1–1.3%) and CGA 55960 (0.7–1.9%) for all groups. The m<strong>in</strong>or amounts of faecal radioactivity<br />

(comb<strong>in</strong>ed, 0.2–1.3%) conta<strong>in</strong>ed partially or all of the ur<strong>in</strong>ary metabolites (Kennedy & Swa<strong>in</strong>,<br />

1992).<br />

An overview of the proposed metabolic pathways of profenofos <strong>in</strong> rats is given <strong>in</strong> Figure 2.<br />

Figure 2. Proposed metabolic pathways of profenofos <strong>in</strong> the rat<br />

Cl<br />

O<br />

OC 2<br />

H 5<br />

Br O P<br />

SC 3<br />

H 7<br />

CGA 15'324<br />

Cl<br />

O<br />

OC 2<br />

H 5<br />

Br O P<br />

SH<br />

CGA 65'867<br />

Cl<br />

O<br />

OH<br />

Br O P<br />

SC 3<br />

H 7<br />

CGA 47'197 1<br />

Cl<br />

O<br />

OC 2<br />

H 5<br />

Br O P<br />

OH<br />

CGA 47'196<br />

Cl<br />

Br<br />

OH<br />

Cl<br />

CGA 55'960<br />

Cl<br />

CO 2 H<br />

Br<br />

Metabolite C<br />

OSO 3<br />

H<br />

Br<br />

O<br />

HO<br />

O<br />

OH<br />

OH<br />

OH<br />

CGA 55'163<br />

PROFENOFOS 403–443 JMPR <strong>2007</strong>

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