Oxidation and O‐dealkylation of sulphamonomethoxine by the turtlePseudemys scripta elegans

Abstract

Sulphamonomethoxine is O-demethylated at the 6 position and oxidised at the 2 position of the pyrimidine substituent by Pseudemys scripta elegans. No N4-acetylation takes place. The yield of the oxidation reaction is twice that of the O-demethylation reaction.

O‐dealkylation and N4‐acetylation of sulpha‐2‐monomethoxine by the turtlePseudemys scripta elegans

“…Therefore the lack of 0-delkylation and Nracetylation of sulpha-2-monomethoxine was unexpected. This is in contrast to the fate of sulphadimethoxine and sulpha-6-monomethoxine in turtles (12,13).…”

“…Recently we have demonstrated that the turtle Pseudemys scripta elegans 0-dealkylates sulphadimethoxine (12), sulpha-6-monomethoxine (13) and sulphamethomidine (15). Moreover sulpha-6-monomethoxine is also oxidised at the 2-position, leading to 2-hydroxysulpha-6-monomethoxine (13). With sulphadimethoxine and sulpha-6-monomethoxine, no Nracetylation takes place in turtles, but this reaction does take place in man and pig.…”

“…The most likely explanation for this lack of information may be that the compound, although synthesised in 1945 by Backer (1), is not microbially active (2,3). Recently we have demonstrated that the turtle Pseudemys scripta elegans 0-dealkylates sulphadimethoxine (12), sulpha-6-monomethoxine (13) and sulphamethomidine (15). Moreover sulpha-6-monomethoxine is also oxidised at the 2-position, leading to 2-hydroxysulpha-6-monomethoxine (13).…”

Elimination Half‐Lives of Sulphadimethoxine and its N4‐acetyl Metabolite in Tissues of Laying Hens

“…It has been already known that one of the main metabolites of sulphonamides in foodproducing animals are N 4 -acetyl derivatives (BRIDGES et al, 1968;NOUWS et al, 1986;VREE et al, 1985) and the major excretory pathway is renal excretion (VREE et al, 1985). Some N 4 -acetylsulphonamides have the following chemical/pharmacological properties: first, lower solubility (pH 7.90) and higher the binding to plasma protein in vitro than the parent compound (VREE and HEKSTER, 1987), which may affect its renal excretion rate; second, de-acetylation to the parent compound occurs in many species such as the chicken (SHAFFER and BIETER, 1950), goat (JORGENSEN and RASMUSSEN, 1972), rabbit (BRIDGES and WILLIAMS, 1963), rat (FUNK and OELSNER, 1970), man (HEKSTER et al, 1981, squirrel monkey (GELBER et al, 1971), pig (SHIMODA et al, 1988), dog (VREE et al, 1984 and turtle (VREE et al, 1989). In the tissues of laying hens in vitro, N 4 -AcSDM was de-acetylated to SDM (FURUSAWA, 1998).…”