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A comparative hazard assessment of the antiparasitics ivermectin, albendazole, and morantel was performed, with a particular focus on bioavailability and uptake into biological membranes. The experimentally determined liposome-water distribution ratio at pH 7 (Dlipw (pH 7)) of the positively charged morantel was 100 L/kg lipid. The Dlipw (pH 7) of albendazole was 3,000 L/kg lipid. The membrane permeability determined with the parallel artificial membrane permeability assay was consistent with predictions from a quantitative structure-activity relationship (QSAR) for morantel but 14-fold lower than predicted for albendazole, which can be rationalized because neutral albendazole is, in fact, zwitterionic and the large dipole moment hinders permeation through hydrophobic membranes. An unusually large molecule, ivermectin was suspected to show decreased bioaccumulation because of its bulkiness, but experimental determination of solubility showed that it was 40-fold less soluble than expected from a QSAR between solubility and the octanol-water partition coefficient. In contrast, its membrane permeability appeared to be typical for a compound of the given hydrophobicity, but it was not possible to determine the membrane-water partition coefficient because of its low solubility and high affinity to the dialysis membrane of the experimental device. The Dlipw (pH 7) for ivermectin of 2,700 L/kg lipid was calculated with a QSAR model. Morantel and albendazole were baseline toxicants in the bioluminescence inhibition test with Vibrio fischeri and a test for inhibition of photosynthesis in green algae. Only ivermectin exhibited a specific effect toward algae, but the excess toxicity was not very pronounced and might be biased by the uncertainty of the estimated hydrophobicity descriptor. Overall, we did not find any unexpected effect on nontarget endpoints. [ABSTRACT FROM AUTHOR]

A test battery for identifying ecotoxicological hazards was applied to six pharmaceuticals (carbamazepine, diclofenac, ethinylestradiol, ibuprofen, propranolol, and sulfamethoxazole), to their mixtures, and to urine spiked with pharmaceuticals to test the suitability of biotests for screening urine and wastewater and for monitoring the efficiency of wastewater treatment. The test battery comprised the bioluminescence inhibition test with Vibrio fischeri, the yeast estrogen screen, and a photosynthesis inhibition assay in algae based on chlorophyll fluorescence measurements. Mixture and additional experiments with a cocktail of pharmaceuticals added to urine confirmed the applicability of the test systems as an integrated measure of the overall micropollutant burden. Because the concentration of pharmaceuticals in wastewater is low and the nutrients and salts may have a negative impact on the bioassays, urine and wastewater samples were cleaned and concentrated by solid-phase extraction (SPE). The compounds of interest ranged from polar to nonpolar and from positively charged to neutral and negatively charged. Consequently, the SPE method was optimized for universality rather than for specificity. Results of preliminary experiments with raw and treated urine and wastewater indicate the suitability of the proposed test battery for screening urine and wastewater. [ABSTRACT FROM AUTHOR]