Table 1.

Summary table containing the most important information discussed in the review, sorted chronologically.

API/active agent (activity, condition treated)	MN system	Matrix composition	Fabrication technique	Effects/conclusions	Ref.
FITC-dextran (model drug) and polyhexamethylene biguanide (model antimicrobial)	detachable hybrid MN pen	MN base: SU-8 resin detachable tip: PLGA	premolding/ pressure-assisted transfer molding	drug containing tip after optimization was delivered to the mouse cornea and efficiently reduced progression of keratitis	[183]
immunoglobulin G (model antiagiogenic agent)	self- implantable microneedle patch	methacrylated HA	cross-linking, molding	due to the double compartment structure of the MNs the rapid release of the anti-inflammatory compound (diclofenac) from the fast dissolving HA-based core provided the synergistic effect with the sustained release of DC101 from the outer layer	[185]
besifloxacin HCl (antibiotic, bacterial infections)	hydrogel MNs	PVA/PVP	micromolding	sufficient mechanical strength to reach 200 µm penetration depth; MNs were much more efficient than traditional suspension	[158]
pilocarpine (reduction of intraocular pressure, glaucoma)	contact lens-shaped MN system	PVA/PVP	micromolding	better permeation across the cornea in vivo in comparison to drug solution	[160]
immunoglobulin G1 (model for bevacizumab molecule)	self-adhesive MN patch	PVA	micromolding with the use of 3D printed master mold	prolonged in vitro release up to 4 weeks in comparison to injection	[178]
—	rapidly detachable MN pen	MN base: SU-8 resin dissolving layer: PVA/PVP detachable tip: PLGA	micromolding	optimization of the composition and manufacturing process enabled almost immediate release of the tip upon contact with tear fluid	[184]
—	Photo- responsive hydrogel MN system	polyvinyl alcohol and spiropyran-conjugated N-isopropylacrylamide	micromolding	easy detachment of the patch after drug release due to the light-induced shrinkage of the matrix	[179]
ovalbumin encapsulated in NPs (model)	fast dissolving MN bilayer patch	PVA	molding, high speed centrifugation	rapid dissolution of MNs, less than 3 min	[182]
fluorescein sodium (model compound)	dissolving MNs	HA/Gantrez® S-97	micromolding	permeation studies on porcine eyeballs showed that due to application of the MN patches the total amount of released dye was close to 18%, whereas from flat patches only 1% was determined after 24 h	[180]
brinzolamide (carbonic anhydrase inhibitor; glaucoma treatment)	dissolving MNs	PVP K90	casting/demolding	rapid in vitro drug release at 2 h, high corneal permeation	[181]
amphotericin B (antifungal)	rapid dissolving MN patch	PVP/HA	micromolding	degradation of the MN up to 30 s, fast onset of drug action	[176]
fluconazole (antifungal)	dissolving MN array patch	PLA/HA	micromolding	satisfactory drug intracorneal pentration with no irritation and tissue recovery up to 12 h	[177]
difluprednate (anti-inflammatory)	rapid dissolving MNs	poly(ᴅ,ʟ-lactide-co-glycolide)	micromolding	matrix diffusion-controlled release over the 7-day	[186]
triamcinolone acetonide (anti-inflammatory)	microneedle scleral patch	PVP	micromolding	greater safety score compared with intravitreal injection	[191]
cyclosporine A (immunosupressant, uveitis and other inflammatory conditions)	dissolving MNs	PVP	micromolding	completely dissolve in the cornea within 60 s, enhanced flux and retention of the drug	[187]