pyronaridine

pyronaridine
IUPAC name	2-methoxy-7-chloro-10-[3,5-bis(pyrrolidin-1-ylmethyl)-4-hydroxyphenyl]benzo[b][1,5]naphthyridine
Width	200
CAS number	74847-35-1
PubChem	68844
DrugBank	DB06614
ChemSpiderID	62066
UNII	8U4MQJ14BQ
ATC prefix	P01
ATC suffix	BF07

pyronaridine. It is a synthetic benzonaphthyridine derivative developed as an antimalarial agent with potent activity against Plasmodium falciparum and Plasmodium vivax. The compound is a key component of the fixed-dose combination therapy pyronaridine-artesunate, which is on the World Health Organization Model List of Essential Medicines for treating uncomplicated malaria. Its development represents a significant achievement in antiparasitic chemotherapy, particularly in regions burdened by drug-resistant malaria.

Chemical properties and structure

The molecular structure of pyronaridine features a complex heterocyclic core, integrating a benzonaphthyridine system with a substituted phenol ring. This aromatic framework is functionalized with methoxy and chloro substituents, alongside dual pyrrolidine rings connected via methylene linkers. The compound is typically formulated as a tetraphosphate salt to enhance its water solubility and oral bioavailability for clinical use. Its chemical synthesis involves multi-step organic reactions pioneered at the Institute of Parasitic Diseases in Shanghai.

Medical uses

Pyronaridine is exclusively used in combination with artesunate as a first-line treatment for acute, uncomplicated malaria caused by Plasmodium falciparum in adults and children. This artemisinin-based combination therapy is recommended by the World Health Organization and is deployed across sub-Saharan Africa and Southeast Asia. The European Medicines Agency granted a positive opinion under its Article 58 procedure, facilitating its use in endemic countries outside the European Union. Clinical trials, such as those conducted by the Medicines for Malaria Venture, have demonstrated high cure rates against multidrug-resistant strains.

Mechanism of action

Pyronaridine exerts its antimalarial effects primarily by inhibiting hemozoin formation within the digestive vacuole of the Plasmodium parasite. The drug intercalates into hematin molecules, preventing their biocrystallization into non-toxic hemozoin, which leads to the accumulation of toxic free heme. This mechanism is analogous to that of chloroquine but with a distinct chemical structure that allows activity against chloroquine-resistant parasites. Additional studies suggest it may also interfere with nucleic acid synthesis by interacting with parasite DNA.

History and development

Pyronaridine was first synthesized in the 1970s by researchers at the Shanghai Institute of Materia Medica following a national antimalarial drug discovery program in the People's Republic of China. Its development was part of a broader response to the spread of chloroquine resistance during the Vietnam War. The compound underwent extensive evaluation by the World Health Organization in the 1990s. The fixed-dose combination with artesunate was later developed through a partnership between Shin Poong Pharmaceutical and the Medicines for Malaria Venture, receiving prequalification by the World Health Organization in 2012.

Adverse effects and precautions

Common adverse effects associated with pyronaridine-artesunate include transient increases in liver enzymes, electrocardiogram QT prolongation, and gastrointestinal symptoms such as vomiting. The U.S. Food and Drug Administration has not approved its use, with prescribing information cautioning against use in patients with severe hepatic impairment. Post-marketing surveillance coordinated by the World Health Organization monitors for potential hepatotoxicity. Its use is contraindicated in individuals with known hypersensitivity to artemisinin derivatives.

Resistance and combination therapy

To delay the emergence of antimalarial drug resistance, pyronaridine is always administered in combination with artesunate, an artemisinin derivative. This strategy leverages the rapid parasite clearance of artesunate and the longer elimination half-life of pyronaridine. Surveillance for molecular markers of resistance is conducted by networks like the WorldWide Antimalarial Resistance Network. The combination remains effective in areas with documented artemisinin resistance in the Greater Mekong Subregion, as per reports from the Centers for Disease Control and Prevention.

Category:Antimalarial agents Category:Heterocyclic compounds Category:World Health Organization essential medicines