Table 1.

Summary of possible strengths and limitations in the use of polymeric nanoparticles as drug delivery systems.

Strengths

-High cell uptake and very low immunogenicity. -Excellent transfection efficiency for nucleic acid drugs. -Good water solubility and simple synthesis, ease in scaling-up. -Flexibility, as the same carrier can be used for different payloads. -Incorporation of hydrophilic and hydrophobic drugs. -Possibility to incorporate targeting moieties or dyes for different biological applications. -Prolonged retention due to size limiting vascular and lymphatic clearance.

Limitations

-Batch-to-batch variation (especially natural polymers). -Limited biodegradability for water-soluble synthetic polymers, which often require incorporation of reducible/cleavable disulfide linkages or acid-labile ester bonds. -For cationic polymers, increased cytotoxicity due to the strong positive charge. -Phagocytosis by tissue-resident macrophages.