Methods and Challenges in Purifying Drug-Loaded Extracellular Vesicles

Extracellular vesicles (EVs) are promising for drug delivery, but challenges in purifying drug-loaded EVs hinder their efficacy. Various methods like ultracentrifugation, density gradient centrifugation, ultrafiltration, and size exclusion chromatography are used, each with advantages and drawbacks. Ultracentrifugation is common but can damage EVs, while density gradient centrifugation preserves integrity but is costly. Ultrafiltration is faster but risks contamination, and size exclusion chromatography effectively separates EVs but may result in low recovery. The document emphasizes the need for standardized purification protocols to ensure accurate drug quantification and therapeutic efficacy, suggesting that tailored and combined methods could improve purity despite increased complexity and cost.