. 2021 Oct 8;13(10):1637. doi: 10.3390/pharmaceutics13101637

Table 1.

Summary of nanofiber-based ocular insert studies.

No	Polymer Base	Loaded Drug/Concentration	Dimensions of Inserts Used	Diameter of Nanofibers	In Vivo/Animal Model	Effects/Properties	References
1	Polycaprolactone (PCL), polyethylene glycol (PEG), sodium alginate (SA), thiolated sodium alginate (TSA)	Besiloxacin HCl (BH) (40 μg per 1 cm²)	3.5 mm² (thickness: 0.66 ± 0.004; diameter: 6.7 ± 0.012)	Less than 1057 nm	Yes, New Zealand albino rabbits	Besifloxacin HCl loaded inserts were developed and investigated in vitro, ex vivo, and in vivo for treatment of bacterial keratitis	[33]
						SA and TSA increased bioadhesion of formulations
						Inserts showed burst release in first 2 days, followed by slow-release profile
2	Poly-lactic-co-glycolic acid (PLGA), polyvinylpyrrolidone (PVP)	Moxifloxacin HCl (1% w/v) pirfenidone (2% w/v)	0.5 cm × 0.5 cm	Drug-loaded fibers were 630 ± 300 nm	Yes, New Zealand male albino rabbits,	Step 1: Successful fiber preparation with encapsulation of two drugs and sustained drug release	[36,51]
2		Moxifloxacin HCl (1% w/v) pirfenidone (2% w/v)	0.5 cm × 0.5 cm	Drug-loaded fibers were 630 ± 300 nm	Yes, New Zealand male albino rabbits,	Step 2: In vivo pharmacokinetic, antimicrobial, and scar healing properties; release rate over 24 h	[36,51]
3	Polylactic acid (PLA), poly(vinyl alcohol) (PVA)	Dexamethasone (1, 5, and 10% w/w)	Thickness of fibers ranged from 50 to 93 μm	Within nanometer size	No in vivo studies have been done	Electrospun nanofibrous inserts were fabricated and compared to solvent casting ocular inserts	[52]
						Electrospun nanofibrous inserts showed first-order release rate
						Results revealed superiority of electrospun nanofibrous inserts over solvent cast inserts
4	Polycaprolactone, poly (lactic-co-glycolic acid), polyvinyl alcohol	Gentamicin (GNT) (10% w/w), methylprednisolone (MP) (6% w/w)	NA	Mean range was 70–650 nm	No in vivo studies have been done	Simple, sandwich, and core-shell nanofibers were prepared and evaluated for dual sustained delivery of gentamicin (GNT) and methylprednisolone (MP)	[53]
4			NA	Mean range was 70–650 nm	No in vivo studies have been done	Core-shell formulation showed best release profile	[53]
5	Hyaluronan (HA), polyvinylpyrrolidone (PVP)	Ferulic acid (FA) (5.7 ± 0.2% w/w)	Mean thickness of 270 ± 21 μm	Approx. 100 nm to 1 μm	No in vivo studies have been done	Development and evaluation of nanofiber inserts for dual release of ferulic acid and ɛ-polylysine (ɛ-PL)	[54]
						Blank inserts released ɛ -PL within 30 min and FA-loaded inserts completely released antioxidant within 20 min
						All formulations were effective against Pseudomonas aeruginosa and S. aureus
6	Poly(1,4-butylene succinate) (PBS)	Triamcinolone acetonide (TA) (2 mg/cm²)	Scaffold disk: 0.4 cm diameter	Range of 1–3 μm	No in vivo studies have been done	Preparation of novel inserts loaded with triamcinolone acetonide	[34]
						Further modification through plasma-induced chemical functionalization
						Formulation resulted in sustained drug release (up to 30 days, Higuchi model) with good compatibility with human cells
7	Chitosan/polyvinyl alcohol/polyvinyl pyrrolidone (CS/PVA-PVP)	Azithromycin (AZM)(10% w/w)	Diameter: 6 mm; thickness: 0.108 ± 0.012 to 0.121 ± 0.002 mm	Mean range of 119.01 ± 29.77 to 171.61 ± 39.40 nm	Yes, New Zealand rabbits	Nanofiber inserts loaded with azithromycin were prepared	[55]
						Stable
						Uniform weight and thickness
						Non-irritating and non-toxic
						Cross-linked nanofibers enabled more controlled drug release than non-cross-linked
8	Polycaprolactone (PCL)	Fluocinolone acetonide (1–5% w/w)	$2 {cm}^{2}$	Average range of 350–400 nm	Yes, New Zealand white rabbits	Development and characterization of preservative-free nanofibrous ocular inserts	[25]
						Homogeneous, non-woven nanofibers
						Burst drug release phase followed by a steady release rate up to 11 days
						High drug permeation to retina
						No ocular irritation
9	Poly(lactic-co-glycolic acid) copolymer/pluronic polyvinylpyrrolidone	Azithromycin (10 m/1 cm²)	$1 {cm}^{2}$	Range of 200–550 nm	Yes, albino rabbits	High bioavailability	[56]
						Highly biodegradable and biocompatible
						Drug release over 10 days
10	Polycaprolactone (PCL),polyvinyl alcohol (PVA)	Timolol maleate (0.5% w/v), and dorzolamide hydrochloride (0.2% w/v)	$1 \times 1 {cm}^{2}$	Range of 200–400 nm	Yes, New Zealand white albino rabbits	Development of nanofibrous patch for insertion into cul-de-sac for treatment of glaucoma	[57]
						Fibers were uniform and smooth
						Results showed significant bioadhesion with sustained drug release up to 24 h
						No ocular irritation with PVA; mild irritation with PLC formulation
						Significant reduction of intraocular pressure
11	Chitosan/polyvinyl alcohol (CS/PVA), Eudragit RL100	Ofloxacin (OFX) (0.6% w/v)	Thickness range: 0.075 ± 0.002 to 0.095 ± 0.002 mm	Average 123 ± 23 to 159 ± 30 nm	Yes, New Zealand white albino rabbits	Two-layer ocular inserts for enhancement of residence time were developed	[58]
						Acceptable morphological and mechanical parameters
						Release up to 95 h
						In vivo studies revealed no ocular irritation
12	Chitosan, polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), Eudragit S100,Zein	Triamcinolone acetonide (1% w/v)	NA	Range of 120 ± 30 to 172 ± 48 nm	No in vivo studies have been done	Development and evaluation of chitosan-based ocular inserts for sustained drug release	[38]
12		Triamcinolone acetonide (1% w/v)	NA	Range of 120 ± 30 to 172 ± 48 nm	No in vivo studies have been done	Prolonged release was obtained (zero-order kinetics)	[38]