Difference between Ornidazole, Levonidazole, and Levonidazole Phosphate Disodium

Ornidazole, Levonidazole, are both approved for the treatment of anaerobic infections and protozoal infections. The structure of Ornidazole contains a chiral carbon atom with a hydroxyl group, which gives it a spin, and the racemates are levonidazole and dexonidazole. The two mainly show differences in elimination, with no significant differences in urinary excretion, plasma protein binding, distribution in the brain, blood-brain barrier permeability, and metabolites, except that the elimination of left ornidazole is faster than that of right ornidazole, and this results in a significant reduction in the incidence of total clinical adverse effects of left ornidazole, whereas right ornidazole is prone to neurotoxicity.

Anti-anaerobic and antiprotozoal effects: left ornidazole ≈ right ornidazole. Toxicity: levonidazole < dexonidazole. Compared with other nitroimidazoles, ornidazole has no inhibitory effect on acetaldehyde dehydrogenase.

Levonidazole water solubility is very poor, usually need to add hydrochloric acid to enhance the water solubility of the drug, injection solution pH is low (3.2 ~ 4.5), easy to produce phlebitis. Compared with levonidazole, the water solubility of disodium levonidazole phosphate is increased, and the pH value is about 5.5 when it is prepared for intravenous administration, and animal experiments have shown that this product does not produce phlebitis.