Methods and Challenges in Purifying Drug-Loaded Extracellular Vesicles

Extracellular vesicles (EV) are promising for drug delivery, but challenges exist in efficiently loading drugs into EV and purifying drug-loaded EV from unloaded drugs. This review examines methods for EV purification, such as ultracentrifugation, density gradient centrifugation, ultrafiltration, size exclusion chromatography, dialysis, and commercial kits, discussing their principles, advantages, and limitations. It highlights critical parameters like molecular weight cutoff and membrane composition that affect purification. The review also considers technical aspects like time, cost, and equipment, stressing the need for standardized guidelines to enhance reproducibility and comparability in EV-based drug delivery research.