Targeted Drug Delivery — From Magic Bullet to Nanomedicine: Principles, Challenges, and Future Perspectives

Figures & data

Figure 1 Generation of drug-delivery systems.

Figure 2 The need for targeted drug delivery.

Figure 3 Principles of drug targeting.

Figure 4 Various categories of drug targeting.

Figure 5 Active vs passive targeting.

Table 1 Differences in nanosomal vesicular carriers

Nanosome	Main component	Uses	Special properties
Niosomes	Cholesterol, charge-inducing substances, nonionic surfactants	Carrier of lipophilic and amphiphilic drugs	Stable, no need for special storage or preparation
Liposomes	Phospholipids dispersed in aqueous solution	Used in targeted oral, topical, and pulmonary DD	Unstable, needs special storage and preparation
Transferosomes	Surfactants, a little alcohol, dye, phosphatadylcholine in buffer solution	Penetrate deeper epidermis layers, used for transdermal delivery	Ultraflexible and deformable vesicles
Ethosomes	High concentration of alcohol, phospholipid, water, cholesterol, dye	Controlled transdermal delivery	Soft and novel vesicles

Table 2 Structural components of dendrimers

Structural Components	Description/Function
Focal point (core)	The center of the dendrimer can be a small molecule, nanoparticle, or polymeric material.
Free (void) spaces	These are empty spaces between the core and interior branchings to be used as room for drug encapsulation or carrying.
Interior branching	Multibranched globular units with internal functional groups that have a covalent framework that connect the dendrimer core with the outer-surface groups.
Exterior groups	These are the outer hydrophilic or hydrophobic surface groups that construct the cover of the dendrimer–drug complex.
Dendrimer–drug linkage	Covalent or noncovalent bond between the dendrimer and the drug.