Table 2.

Comparison for advantages and disadvantages of different flexible polymeric patches.

Polymeric matrix	Advantages	Disadvantages
MN	Precise drug loading; High drug loading efficiency; Realizing instant transdermal drug delivery; Unique capability of swelling; Allowing attachment of drug reservoir; No measurable polymer residue leaving; Extracting the interstitial fluid from the skin and release of pre-loaded drugs; Easy remove after treatment; Treatment can be momentarily stopped; Proper biosafety and repeated use	Need more waiting-time to completely dissolve before removing the patch; Only used in epidermal disease treatment Limited drug loading into the polymeric matrix
Hydrogel	High drug loading efficiency; Unique capability of swelling; Usually employed for sustained drug release	Polymer residues found in skin within a few days; Influence of cross-linking conditions on bioactivity of drugs; Easy leaky of drug during delivery
Microsphere/microcapsule	Increasing drug loading efficiency through encapsulation or coating;	Polymer residues found in skin within a few days; Slow self-degradation; Easy leaky of drug during delivery