Effects Of β-Cyclodextrin And Its Derivatives On The Solubilization And Toxicity Of Several Pesticides

Based on the methods that the recent references reported, two high soluble derivatives of P -cyclodextrin( P -CD), hydroxypropyl- P -cyclodextrin (HPCD) and hydroxyethyl- P -cyclodextrin (HECD), were prepared in this paper. The effects of P -CD, HPCD and HECD on the solubilization of three hydrophobic organic pesticides (methyl parathion, carbofuran, pentachlorophenol) and the biotoxicity of methyl parathion were investigated. The main results are as follows.The solubilities of pentachlorophenol and carbofuran were linearly increased with increasing P -CD concentration. At the temperature of 25癈, in 6g/l P -CD solution, the solubilities of pentachloropenol and carbofuran were increased by 3.76 and 1.76 times respectively. But the solubility of methyl parathion was increased originally and then decreasd with increasing β-CD concentration.The solubilities of three pesticides were linearly increased with increasing HPCD and HECD concentration. In 75g/l HPCD solution, the solubilities of methyl parathion, carbofuran and pentachloropenol were increased by 61.9, 6.0 and 27.2 times respectively. In 60g/1 HECD solution, the solubilities of three pesticides were increased by 29.62, 3.59 and 23.56 times respectively. HPCD and HECD are higher soluble than P -CD, so the solubilization effects of HPCD and HECD on the pesticides are more significant than that of P -CD. This phenomenon is especially obvious for methyl parathion.The solubilization effects of β-CD, HPCD and HECD are caused by formation of inclusion complexes of hydrophobic organic pesticides with P -CD, HPCD or HECD. The degree of solubilization power is first depended on the degree of fitness of pesticide structures with the cavity of β-CD and then the lipophilisity of the pesticides.The LC50S of methyl parathion and the inclusion complexes of methyl parathion with P -CD, HPCD and HECD to tadpole at various relative treatments were close. Especially their LC50s of 96 hours were very close, which revealed that the addition of P -CD, HPCD and HECD had no effects on the biotoxicity of methyl parathion.Author:Luo YuechuD i rected by: Professor Yang RenbinAssociate Professor Zeng Qingru...