title: New formulation of paraquat with lysine acetylsalicylate with low mammalian toxicity and effective herbicidal activity.
abstract: BACKGROUND
  Currently, the commercial formulations of the herbicide paraquat are highly toxic to humans, and no effective antidote is available for paraquat poisoning. The aim of the present study was to develop a safe formulation, combining paraquat and the known antidote lysine acetylsalicylate. The toxicity of a mixture of Gramoxone® (20% paraquat) and lysine acetylsalicylate in adult Wistar male rats and the herbicidal efficacy against grass lawn (50% of Poa pratensis and 50% of Festuca arundinacea) were evaluated. This new formulation was administered to Wistar rats by gavage at 125 mg kg(-1) of paraquat ion and lysine acetylsalicylate at 79, 158 or 316 mg kg(-1) body weight, and the survival rate was observed for 30 days.
  
  
  RESULTS
  The survival rate of the paraquat group was only 40%, while lysine acetylsalicylate provided effective protection, with full survival observed in the groups that received 125 mg kg(-1) of paraquat ion and 316 mg kg(-1) of lysine acetylsalicylate. Both formulations of paraquat, either in the absence or in the presence of lysine acetylsalicylate, provided the same herbicidal activity against the tested herbal species.
  
  
  CONCLUSIONS
  The present formulation of paraquat containing lysine acetylsalicylate, significantly decreases mammalian toxicity while maintaining effective herbicidal activity.
authors.affiliation: REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Baltazar
authors.forename: Ricardo Jorge
authors.initials: RJ
authors.lastname: Dinis-Oliveira
authors.forename: Lúcia
authors.initials: L
authors.lastname: Guilhermino
authors.forename: Maria de Lourdes
authors.initials: Mde L
authors.lastname: Bastos
authors.forename: José Alberto
authors.initials: JA
authors.lastname: Duarte
authors.forename: Félix
authors.initials: F
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D000931:Antidotes / Q000494:pharmacology*; D001241:Aspirin / Q000031:analogs & derivatives* / Q000494:pharmacology; D006540:Herbicides / Q000633:toxicity*; D008239:Lysine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D010269:Paraquat / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D018675:Toxicity Tests
chemical_list: D000931:Antidotes; D006540:Herbicides; D008239:Lysine; D010269:Paraquat; D001241:Aspirin; C010395:acetylsalicylic acid lysinate