Analysis of drugs and pharmaceuticals in the environment is typically performed with non-chiral chromatographic techniques. The environmental risks posed by chiral compounds analysed in this way must therefore be assumed to be independent of chirality, meaning that each enantiomer is equally potent in toxicity and long-lived in stability. This manuscript examines the degradation of each of the four isomers of ephedrine in river simulating microcosms and links this to toxicity data obtained by exposing three different organisms (D. magna, P. subcapitata and T. thermophila) to each of the isomers individually. Microcosms showed that significant degradation only occurred in biotic conditions and that only two isomers (1R,2S-(-)-ephedrine, 1S,2S-(+)-pseudoephedrine) degraded significantly over a period of fourteen days. This is concerning because at least one of the non-degraded isomers (1S,2R-(+)-ephedrine) has been observed in wastewater effluent, which discharges directly into rivers, meaning these isomers could be persistent in the environment. We also observed formation of 1S,2R-(+)-ephedrine in single isomer 1R,2S-(-)-ephedrine river simulating microcosms. Human liver microsome assays and mass spectrometry based data mining revealed that 1S,2R-(+)-ephedrine is not human derived but it could be formed as a results of microbial metabolic processes. Across all three organisms tested the persistent isomers (1S,2R-(+)-ephedrine and 1R,2R-(-)-pseudoephedrine) were more toxic than those that undergo degradation; meaning that if these isomers are entering or formed in the environment they might represent a potentially hazardous contaminant.

通常使用非手性色谱技术进行环境中药物的分析。因此，必须假定以这种方式分析的手性化合物所构成的环境风险与手性无关，这意味着每种对映异构体均具有相同的毒性，并且具有长寿命的稳定性。该手稿检查了模拟河水中麻黄碱的四种异构体各自的降解，并将其与通过将三种不同的生物（D. magna，P。subcapitata和T. thermophila）分别暴露于每种异构体而获得的毒性数据相关联。微观世界表明，只有在生物条件下才会发生明显的降解，并且只有两种异构体（1R，2S -（-）-麻黄碱，1S，2S-（+）-伪麻黄碱）在十四天内显着降解。这是令人担忧的，因为在废水中至少观察到一种未降解的异构体（1S，2R-（+）-麻黄碱），其直接排放到河流中，这意味着这些异构体可能在环境中持久存在。我们还观察到模拟单一世界的单一异构体1R，2S -（-）-麻黄碱中1S，2R-（+）-麻黄碱的形成。人肝微粒体测定和基于质谱的数据挖掘表明，1S，2R-（+）-麻黄碱不是人衍生的，但可能是由于微生物代谢过程而形成的。在所有这三种生物中，测试了持久性异构体（1S，2R-（+）-麻黄碱和1R，2R -（-）-伪麻黄碱）的毒性比被降解的毒性更高；这意味着，如果这些异构体进入或在环境中形成，它们可能代表潜在的危险污染物。