Sex-related differences in disposition of sulfamethoxazole, N-acetyl- sulfamethoxazole and trimethoprim in yellow catfish ( Pelteobagrus fulvidraco ) following a single oral administration

The aim of this present study was to explore the sex-related differences in disposition regularities of sulfamethoxazole (SMZ), N-acetyl-sulfamethoxazole (N-ac-SMZ) and trimethoprim (TMP) in male and female yellow catfish. Concentrations of target compounds were determined using a reliable HPLC-MS/MS approach, which was validated according to the guidelines defined by FDA. The results showed that there are significant sexassociated differences in SMZ concentrations of muscle with skin and liver, in N-ac-SMZ levels of muscle with skin and kidney, and in TMP concentrations of muscle with skin, liver and kidney. Whereas, no significant sex differences were also observed in SMZ, N-ac-SMZ and TMP levels of plasma, in SMZ concentrations of kidney and in N-ac-SMZ concentrations of liver. Longer residue time of N-ac-SMZ than SMZ was observed in male and female yellow catfish. Withdrawal time (WT) of SMZ (N-ac-SMZ as the marker residue) calculated by the WT 1.4 software, was 11 days (male) and 9 days (female), respectively. By contrast, WT of SMZ (SMZ as the marker residue) was 9 days (male) and 7 days (female), respectively. These results could serve as reference data for establishing disparate use regimen and drug withdrawal time of SMZ and TMP in male and female yellow catfish.

Automated summary

The study revealed significant sex-related differences in the disposition regularities of SMZ, N-ac-SMZ, and TMP in male and female yellow catfish. N-ac-SMZ showed a longer residue time compared to SMZ, and the findings could serve as reference data for establishing different use regimens and drug withdrawal times.