Fabrication of nanostructured lipid carriers ocugel for enhancing Loratadine used in treatment of COVID-19 related symptoms: statistical optimization, in-vitro, ex-vivo, and in-vivo studies evaluation

Abstract

Loratadine (LORA), is a topical antihistamine utilized in the treatment of ocular symptoms of COVID-19. The study aimed to develop a Loratadine Nanostructured Lipid Carriers Ocugel (LORA-NLCs Ocugel), enhance its solubility, trans-corneal penetrability, and bioavailability. full-factorial design was established with 2⁴ trials to investigate the impact of several variables upon NLCs properties. LORA-NLCs were fabricated by using hot melt emulsification combined with high-speed stirring and ultrasonication methods. All obtained formulae were assessed in terms of percent of entrapment efficiency (EE%), size of the particle (PS), zeta potential (ZP), as well as in-vitro release. Via using Design Expert® software the optimum formula was selected, characterized using FTIR, Raman spectroscopy, and stability studies. Gel-based of optimized LORA-NLCs was prepared using 4% HPMC k100m which was further evaluated in terms of physicochemical properties, Ex-vivo, and In-vivo studies. The optimized LORA-NLCs, comprising Compritol 888 ATO^®, Labrasol^®, and Span^® 60 showed EE% of 95.78 ± 0.67%, PS of 156.11 ± 0.54 nm, ZP of -40.10 ± 0.55 Mv, and Qh6% of 99.67 ± 1.09%, respectively. Additionally, it illustrated a spherical morphology and compatibility of LORA with other excipients. Consequently, gel-based on optimized LORA-NLCs showed pH (7.11 ± 0.52), drug content (98.62%± 1.31%), viscosity 2736 cp, and Q12% (90.49 ± 1.32%). LORA-NLCs and LORA-NLCs Ocugel exhibited higher ex-vivo trans-corneal penetrability compared with the aqueous drug dispersion. Confocal laser scanning showed valuable penetration of fluoro-labeled optimized formula and LORA-NLCs Ocugel through corneal. The optimized formula was subjected to an ocular irritation test (Draize Test) that showed the absence of any signs of inflammation in rabbits, and histological analysis showed no effect or damage to rabbit eyeballs. C_max and the AUC_0-24 were higher in LORA-NLCs Ocugel compared with pure Lora dispersion-loaded gel The research findings confirmed that NLCs could enhance solubility, trans-corneal penetrability, and the bioavailability of LORA.

Keywords: Draize test; Loratadine (LORA); confocal laser scanning microscopy (CLSM); nanostructured lipid carriers; pharmacokinetic studies; reducing of COVID-19 ocular symptoms.

Figure 1.

Linear plot of the effect of formulation variable on EE% (a–c), PS (d–g), and ZP (h–j). EE%; Entrapment Efficiency Percent, PS; Particle Size, ZP; Zeta Potential; SAA; Surface Active Agent, LORA; Loratadine, NLCs; Nanostructure Lipid Carriers.

Figure 2.

Linear plots for the effect of (X2) type of liquid lipid on Q6h. Q6h; Amount of drug released after 6 hours.

Figure 3.

FTIR spectra of pure Loratadine (LORA) and each pharmaceutical excipients of the optimized formula LORA-NLCs separately, and the optimized formula LORA-NLCs.

Figure 4.

Raman spectra of pure Loratadine powder (LORA) and optimized formula (LORA-NLCs-2).

Figure 5.

Transmission electron micrograph of the optimized LORA-NLCs-2.

Figure 6.

Cumulative amount of LORA permeated per unit area across excised bovine cornea via NLCs and NLCs Ocugel relative to LORA aqueous solution. Data were illustrated as mean ± S.D; n = 3.

Figure 7.

A tile scan confocal laser microscope photomicrograph of a longitudinal section in bovine cornea treated with FDA-loaded NLCs, and NLCs Ocugel. Note: (1) NLCs ocugel, (2) optimized NLCs, (A) Fluorescence light, and (B) merge between fluorescence light and transmitted light. Abbreviations: FDA, fluorescein diacetate; NLCs, nanostructure lipid carriers.

Figure 8.

Histopathology microscopy of the cornea (1), ciliary body (2), iris (3) after treatment with the optimized formula of 21 days. Notes: (A) Control; (B) treated, (bold arrow) Showing outer epithelium, (arrowhead) inner endothelium, (S) intermediate stroma, and (arrow) keratocyte.