Table 1.
Transdermal drug delivery systems covered in the review.
| Category | Technology | In Vivo Evaluation | Clinical Trial | Pros | Cons | Ref. |
|---|---|---|---|---|---|---|
| Chemical permeation enhancer (CPE)-based systems | Biphasic vesicles | Yes (guinea pig) | Phase II | Sustained release Versatility (small and large molecules) |
Control of the delivered dose | [15,16,17,18,19,20,21,22,23,24] |
| Ionic liquids (ILs) and active pharmaceutical ingredient-ionic liquids (API-ILs) | Yes (rats) | N/A | APIs with enhanced skin permeation properties of ionic liquids Properties can be fine-tuned |
Requires specific choice of counter-ions Limited to small molecules |
[42,43,47] | |
| Physical enhancer-based systems | Hollow microneedles | Ex vivo: rabbit ear skin | Completed | Large doses Versatility |
Manufacturing cost Potential clogging Skilled personnel |
[53,54] |
| Nanoparticle-based systems | Lecithin-based microemulsions | N/A | N/A | Low skin irritation Sustained release and higher permeation compared to standard emulsions |
Lecithin could lead to skin permeation complications | [61,64,65,69] |
| Archaeosomes | N/A | N/A | Versatility Sustained release |
Biocompatibility unclear Permeation mechanism unclear |
[74] | |
| Carbon nanotubes (CNTs) | Yes (mice) | N/A | Effective skin permeation without CPEs High drug loading |
Complexity Biocompatibility unclear |
[81] |