Preclinical safety evaluation of levonadifloxacin, a novel anti-methicillin-resistant Staphyloccocus aureus benzoquinolizine fluoroquinolone by intravenous and oral administration.

Fluoroquinolone (FQ) antibacterials have drawn heightened attention from various international regulatory agencies due to their class-specific side effects. Levonadifloxacin is a novel broad spectrum benzoquinolizine FQ active against methicillin-resistant Staphyloccocus aureus (MRSA). Owing to FQ-associated safety concerns, extensive preclinical safety pharmacology (central nervous system and cardiac safety) and toxicology studies (subacute repeat-dose toxicity, genotoxicity, phototoxicity and chondrotoxicity) of levonadifloxacin were performed at relatively high doses.

Preclinical safety evaluation of nafithromycin (WCK 4873) with emphasis on liver safety in rat and dog.

Ketolide antibiotics are known to cause hepatic injury. Nafithromycin, a novel lactone ketolide was therefore assessed for hepatic safety through range of preclinical in vitro (metabolic stability, CYP inhibition/induction assays) and in vivo (mass balance and repeat dose toxicity) studies. Repeat-dose toxicity studies in rat and dog revealed that nafithromycin did not cause adverse hematological, biochemical and histopathological changes suggestive of systemic or hepatobiliary safety concern at exposures 3-8 fold higher than targeted therapeutic exposures.