Prodrug

Prodrug designates a pharmacologically inactive compound designed to undergo metabolic or chemical conversion within the body, transforming into an active therapeutic agent at the target site. This strategic approach addresses drug development challenges including poor bioavailability, tissue selectivity, toxicity reduction, and formulation difficulties.

Classic examples include enalapril, which converts to the active ACE inhibitor enalaprilat, and oseltamivir (Tamiflu), which requires hepatic metabolism to generate its active antiviral form. Antibody-drug conjugates represent sophisticated prodrugs where cytotoxic agents remain inert until antibodies deliver them to tumour cells. Approximately 10-20% of approved drugs function as prodrugs, demonstrating this strategy's proven value. Companies employ prodrug design to enhance oral bioavailability, mask unpleasant tastes in paediatric formulations, or achieve sustained release profiles. Regulatory frameworks recognise prodrugs as distinct entities requiring comprehensive metabolic characterisation and appropriate preclinical safety assessments. Advanced computational chemistry and structural biology tools enable rational prodrug design with predictable activation kinetics. As the industry pursues increasingly challenging molecular targets, prodrug strategies continue expanding the druggable space while improving safety and patient convenience.