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The sustained release of alprenolol, a β-adrenergic antagonist, could be beneficial for the treatment of various heart diseases while reducing the side effects resulting from its continuous use. The novel and branched copolymers uniquely composed of biodegradable components (lactide and glycolide) have been synthesized using natural and therapeutically-efficient aescin-initiator, and consequently characterized to determine their structures and physicochemical properties. The obtained matrices were not cyto- and genotoxic towards bacterial luminescence, protozoan, and Salmonella typhimurium TA1535. The copolymers release the drug in vitro in a sustained manner and without burst release. The value of the drug released was strongly dependent on the copolymer composition and highly correlated with the hydrolytic matrices' degradation results. [ABSTRACT FROM AUTHOR]

In this study the toxicity of selected sunscreens be- longing to two chemical groups: i.e. derivatives of cinnamic acid and of benzoic acid was assessed. The compounds are found in suncare products (creams, balms and lotions) and in other cosmetics (antiwrinkle creams or lipsticks). Two of them (octyl methoxycinnamate and octyl (dimethylamino)- benzoate) are approved for use as ingredients of cosmetic products in the European Union countries. The Rotoxkit F Chronic bioassay was used to evaluate the toxicity of seven compounds, the organisms (the rotifer Brachionus calyc(florus) being hatched from dormant eggs purchased from MicroBioTests®, (Belgium). Two of the study compounds octyl methoxycinnamate and octyl (dimethylamino)benzoate proved to be the most toxic to rotifers. The toxicity correlated highly with the au- phatic chain structure and lipophilic properties of the com- pounds as the substances with the highest log P value and a high affinity for lipids, i.e. octyl methoxycinnamate and octyl (dimethylamino)benzoate, demonstrated the highest toxicity. [ABSTRACT FROM AUTHOR]

The toxicity of zinc and copper oxides was studied with the Spirotox and Protoxkit F™ assays at various pH levels from acidic (5.5), through neutral (7.0) to basic (8.0) conditions. The protozoan S. ambiguum was much more sensitive to metals than T. thermophila. All zinc formulations were similarly toxic to S. ambiguum and T. thermophila with 24h-EC50 of 0.71 mg l-1 and 11.5-13.5 mg l-1, respectively. Biological activity of the copper formulations greatly depended on the formulation and on pH of the medium. In the Spirotox test nanoparticles (CuO-n) and bulk particles (CuO-b) were 31 and 790-fold less toxic than copper(II) ion, respectively. The toxicity of copper(II) sulfate and CuO-n decreased 3.4 and 6.8-fold with the increase of pH from 7.0 to 8.0, respectively. For evaluation of the influence of surfactants on the toxicity of zinc and copper oxides non toxic levels of anionic (SDS, 1 mg l-1) and nonionic (Triton X-100, 4 mg l-1) surfactants were applied. No influence of the surfactants on the toxicity of metal oxides was observed in the Protoxkit F™. In the Spirotox assay both surfactants did not affect the toxicity of zinc oxides, while SDS and Triton X-100 caused 20 and 40% increase of CuO-n toxicity, respectively. [ABSTRACT FROM AUTHOR]

Cyanobacterial (blue-green algal) blooms are one of the common consequences of the increasing eutrophication of surface waters. The production of cyanobacterial toxins and their presence in drinking and recreational waters represents a growing danger to human and animal health. Due to a lack of toxin standards and to resource limitations on the wide-scale use of analytical methods (e.g., high-performance liquid chromatography, enzyme-linked immunosorbent assay (ELISA)) in cyanobacterial toxin monitoring, it is necessary to assess and to develop additional methods for their detection and estimation. Microbiotests using invertebrates offer a possible approach for the inexpensive andstraightforward detection and assessment of cyanobacterial bloom toxicity. Three microbiotests with: Thamnocephalus platyurus, Daphnia magna, and Spirostomum ambiguum were examined with bloom samples containing hepatotoxic microcystin-LR and up to five additional microcystinvariants. Two kinds of cyanobacterial bloom sample preparations weretested: crude extracts (CE) and purified extracts (PE). The highest toxicity was found when CE was used for microbiotests. The sensitivity of microorganisms decreased from S. ambiguum to T. platyurus and toD. magna. A statistically significant correlation was found between microcystin concentration and T. platyurus biotest, and between mousebioassay and S. ambiguum results. Addition of Me2SO (1%, v/v) is a possible method to increase the sensitivity of the microorganisms for microcystin-LR. [ABSTRACT FROM AUTHOR]