Table 1.

Comparison of MNs over different dosage forms

Description	Topical cream	Parenteral injection	Transdermal patch	Trans-epidermal
The molecular weight of drugs	Insufficient for high molecular weight drugs	Insufficient for high molecular weight drugs	Insufficient for high molecular weight and lipophilic drugs	Serves as a potential delivery route for both low and high molecular weight drugs
Bioavailability	10–20% (poor)	100% (sufficient)	Insufficient	Sufficient
Onset of action	Slow	Faster	Slow	Fast
Pain	Painless	Painful	Painless	Painless
Self-administration	Possible	Impossible	Possible	Possible
Patient compliance	Less	Less	Better	Better
Mechanism of drug delivery	Pores act as a drug carrier system	Drug enters directly into the dermis	Poor permeability across stratum corneum	Drug directly enters the epidermis, bypasses the stratum corneum and increases the permeability
Microneedle size	-	1.5–4 mm long needle	10–40 µm long needle	150–1500 µm long needle