Table 4.

Lipid nanoparticle preparation methods and their potential applications in retina diseases.

Lipid Nanoparticle	Method of the Preparation	Characterization	Applications	Refs.
Dioctadecyl dimethyl ammonium bromide, glyceryl monostearate, soy phosphatidylcholine, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE)- PEG2000-maleimide	Film-ultrasonic	Solid lipid nanoparticles (SLNs) were prepared and loaded with miRNA-150 and quercetin for treating AMD. Both miRNA and quercetin-loaded SLNs exhibited a particle size between 115 to 209 nm.	The formulation was developed as an intravitreal injection and injected in a mouse model. The developed formulation suppressed the choroidal angiogenesis effectively. Due to the synergetic effect of both the therapeutic agents, the SLNs were able to lower the choroidal neovascularization.	[124]
1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), hydrogenated soy phosphocholine, methoxy PEG2000-DSPE	Thin-film hydration	Lipopolyplexes were prepared by co-formulating polyethyleneimine and lipid nanoparticles to treat diabetic retinopathy. The lipopolyplexes were loaded with human antigen R (HuR), a VEGF-regulating protein. The formulation showed an average particle diameter of 200–250 nm.	The formulation was injected into Wistar rats intravitreally. After treating the streptozotocin-induced diabetic rats, the formulation significantly lowered the retinal HuR and VEGF levels.	[125]
Chitosan, glyceryl monostearate, linoleoyl polyoxyl-6-glycerides (Labrafil M 2125 CS)	Melt emulsification–ultrasonication	5-fluorouracil (5-FU) was loaded into the chitosan-modified lipid nanoparticles to treat diabetic retinopathy. The developed lipid nanocarriers displayed particle sizes around 163.2 ± 2.3 nm.	The formulation was developed as a non-invasive topical formulation. The formulation showed controlled release of 5-FU, and streptozotocin-induced diabetic rats showed significant therapeutic efficacy.	[126]
Medium-chain triglycerides, dioctadecyl-3,3,3,3 tetramethylindodicarbocyanine (DiO), polyethylene glycol (15)-hydroxy stearate, hydrogenated phosphatidylcholine	Phase inversion	CN03, a cyclic guanosine-3,5-monophosphate analog, was delivered using lipid nanocarriers for treating inherited retinal degenerations. The prepared lipid nanoparticles displayed a particle size of approximately 72 nm.	The formulation efficacy was tested via both topical and intravitreal administration. The lipid nanocarriers increased permeability, and the CN03 formulation protected the rd1 mouse photoreceptors when tested in retinal explants, making them ideal for treating inherited retinal degenerations.	[127]
Poloxamers 407/188, glycerol tripalmitate (GTP), soybean lecithin, stearic acid, PLGA	Emulsification	CN03-loaded lipid nanoparticles were prepared using w/o/w emulsification for treating posterior retinal diseases. The prepared CN03-loaded nanoparticles displayed a particle size of approximately 200–250 nm with good encapsulation efficiency.	The formulation was developed for use via intravitreal delivery. The formulation demonstrated excellent cellular uptake in retinal cell lines and released the loaded cargo inside the cells.	[128]
Glyceryl di behenate (Compritol 888), behenoyl polyoxyl-8 glycerides (Compritol HD5 ATO)	Microemulsion	Bbetulinic acid derivative (H3, H5, and H7)-loaded lipid nanoparticles were prepared to protect the Müller cells from oxidative stress injury and maintain hemostatic functions in the retina.	The formulation was designed for systemic administration. MIO-M1 cells treated with the H5-loaded lipid nanoparticles reduced glutamate-induced ROS formation and related cell death.	[129]
Di Stearoyl phosphatidylcholine (DSPC), sterols, 1,2-dimyristoyl-rac-glycero-3-methoxy polyethylene glycol (DMG-PEG)	Rapid microfluidic mixing	Gene delivery for treating inherited retinal degenerations was designed by loading mCherry mRNA in lipid nanoparticles. The mRNA-loaded lipid nanoparticles exhibited a particle size below 80 nm, with more than 90% high encapsulation.	The formulation was administered in mice via subretinal injections. The study demonstrated the feasibility of delivering genes to the photoreceptors and retinal pigment epithelium.	[130]
Lauroyl PEG -32 glycerides, propylene glycol monocaprylate, hydrogenated coco glycerides	Hot-melt emulsification and ultrasonication	Diosmin-loaded lipid nanoparticles were prepared to treat diabetic retinopathy. The critical parameters of the nanoparticles, such as particle size and PDI, were identified and optimized using the Box–Behnken design. The optimized formulation had a particle size of approximately 85 nm, with a high encapsulation efficiency of 99%.	A topical delivery of Diosmin-loaded nanoparticles was designed and developed to treat DR. The compatibility of the formulation was tested on a human retinal pigment epithelial cell line (ARPE-19). The free drug, Diosmin, showed reduced cell viability; the highest concentration resulted in 54% of cell death, and the formulations showed no significant reduction of cell viability.	[131]
DSPE-PEG, PLGA, soybean lecithin	Membrane hydration and high-power ultrasonic method	The formulations showed a mean particle size ranging from 99–127 nm. The surface charge was −32.0 ± 1.1 mV for blank formulation. After modification with peptides, the surface charge became positive. The drug loading efficiency was 1.03% with the membrane hydration method, whereas the drug loading significantly increased with the ultrasonic method.	A non-invasive drug delivery system was developed for the delivery of Axitinib. This study uses non-invasive delivery of Axitinib-loaded lipid nanoparticles for treating oxygen-induced retinal neovascularization in the posterior cavity and laser-induced AMD. A transmembrane peptide (PENE) was added to the nanoparticles to increase the transmembrane delivery. The nanomedicine effectively inhibited neovascularization due to improved tissue penetration of the nanoparticles.	[132]