Halogenation of Pharmaceuticals Is an Impediment to Ready Biodegradability

For pharmacological reasons many active organic pharmaceutical substances (AOPSs) are singly or multiply halogenated. Halogenation can confer optimised steric fitting of an AOPS to its molecular receptor; moreover, by increasing the lipophilicity a compound, passive permeation through bilipid membranes into target cells is enhanced. As halogenation widely suspected inhibit biodegradability in wastewater treatment plants, relationship vs. ready was investigated. Among 230 AOPSs with empirical data, all 70 halogenated not readily biodegradable, and confirmed be impediment biodegradability. counterexample halogenation, hydrophilic substitutions (hydroxy, carboxylic-acid terminal-amine groups) positively correlated Regarding therefore, goals stand stark contrast environmental goals. Possible ideas toward solutions for this contradiction discussed.