Novel lutein loaded lipid nanoparticles on porcine corneal distribution

Abstract

Topical delivery has the advantages including being user friendly and cost effective. Development of topical delivery carriers for lutein is becoming an important issue for the ocular drug delivery. Quantification of the partition coefficient of drug in the ocular tissue is the first step for the evaluation of delivery efficacy. The objectives of this study were to evaluate the effects of lipid nanoparticles and cyclodextrin (CD) on the corneal lutein accumulation and to measure the partition coefficients in the porcine cornea. Lipid nanoparticles combined with 2% HPβCD could enhance lutein accumulation up to 209.2 ± 18 (μg/g) which is 4.9-fold higher than that of the nanoparticles. CD combined nanoparticles have 68% of drug loading efficiency and lower cytotoxicity in the bovine cornea cells. From the confocal images, this improvement is due to the increased partitioning of lutein to the corneal epithelium by CD in the lipid nanoparticles. The novel lipid nanoparticles could not only improve the stability and entrapment efficacy of lutein but also enhance the lutein accumulation and partition in the cornea. Additionally the corneal accumulation of lutein was further enhanced by increasing the lutein payload in the vehicles.

Figure 1

Dose effect of lutein on corneal accumulation using 2% HPβCD combined NLCs.

Figure 2

Effect of vehicles on lutein corneal accumulation. The lutein content in all vehicles is 2000 μg/g.

Figure 3

TEM photographs for NLC(A) and NLC + 2% HPβCD (100000x). Scale bar in (a) and (b) represents 100 and 50 nm, respectively. The size of the NLCs was 190 and 360 nm, respectively.

Figure 4

Size stability and zeta potential of lutein loaded vehicles after one month storage, n = 3.

Figure 5

Lutein distribution in porcine cornea after 24 h treatment observed by using confocal laser scanning microscopy. Lutein fluorescence emitted at 515 nm was recorded when excited at a wavelength of 488 nm by means of an argon laser. The sample was scanned from the tissue surface (0 μm) to a depth of 352 μm at a 29.3 μm interval.

Figure 6

Micrographs of HE staining after 24 h treatment with PBS (a) and NLC + 2% HPβCD (b). Arrow indicates the epithelium. Scale bar represents 25 μm. Porcine cornea after 24 h treatment was fixed, stained, and observed using light microscopy.

Figure 7

Cytotoxic effect of vehicles on bovine cornea epithelium cells: (a) vehicle only and (b) lutein loaded vehicles.