The Draize Test and Modifications

The Use of an Opacitometer to Compare the In Vitro Cornea Opacifying Effects of Timolol With and Without Benzalkonium Chloride

Alternatives to Laboratory Animals ◽

10.1177/026119299101900220 ◽

1991 ◽

Vol 19 (2) ◽

pp. 263-270

Author(s):

Haruyoshi Igarashi ◽

Yasunaga Katsuta ◽

Yoshiharu Nakazato ◽

Tohru Kawasaki

Keyword(s):

Benzalkonium Chloride ◽

Additive Effects ◽

Timolol Maleate ◽

Epithelial Surface ◽

Endothelial Surface ◽

Draize Test ◽

Corneal Opacities

We have evaluated a new in vitro opacitometer method as an alternative to the in vivo Draize test for ocular irritancy. Several concentrations of timolol maleate (timolol) with or without 0.005% benzalkonium chloride were applied to porcine isolated corneas which were either intact or with the epithelium, endothelium, or both epithelium and endothelium removed. Corneal opacities were measured using an opacitometer. In general, timolol with benzalkonium chloride caused a greater degree of opacity to develop in the cornea than did timolol alone. At the lower concentrations of timolol, the increased opacity probably represented additive effects of the two compounds. However, at the highest concentration of timolol (5 x 10 2M), there was an enhanced opacification in the presence of benzalkonium chloride, which may have been due to an increase in penetration, particularly through the epithelium. Timolol caused a greater degree of opacity to develop in the isolated intact porcine corneas when the drug was applied to the endothelial surface, than when applied to the epithelial surface or to both the epithelial and endothelial surfaces. However, timolol with benzalkonium chloride caused a greater degree of opacity in the intact cornea, when the drug was applied to both surfaces than when it was applied only to the epithelial or the endothelial surface.

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Use of the 3T3 cell-neutral red uptake assay for irritants as an alternative to the rabbit (Draize) test

Food and Chemical Toxicology ◽

10.1016/0278-6915(86)90096-7 ◽

1986 ◽

Vol 24 (6-7) ◽

pp. 473-475 ◽

Cited By ~ 34

Author(s):

K. Hockley ◽

D. Baxter

Keyword(s):

Neutral Red ◽

Draize Test ◽

Uptake Assay ◽

Neutral Red Uptake ◽

Neutral Red Uptake Assay

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Ophthalmic Delivery of Riboflavin Loaded Nanoparticulate Suspension in Keratoconus: A Preclinical Study in Rabbit Model

Journal of Biomedical Nanotechnology ◽

10.1166/jbn.2021.3156 ◽

2021 ◽

Vol 17 (9) ◽

pp. 1866-1873

Author(s):

Ling Zhang ◽

Chunlai Fang ◽

Qiong Wu

Keyword(s):

Spherical Surface ◽

Rabbit Model ◽

Preclinical Study ◽

Solvent Evaporation Method ◽

Experimental Animals ◽

Ophthalmic Administration ◽

Draize Test ◽

Ophthalmic Delivery ◽

Probe Sonication

The present investigation undertakes the formulation of nanoparticulate suspension of Riboflavin to treat keratoconus disease by applying it to the infected mice corneas. The nanoparticles of Riboflavin were prepared using single solvent evaporation method and later formulated as suspension using continuous probe sonication method. Then, both riboflavin nanoparticles and suspension were evaluated for various parameters. The nanoparticles showed smooth and spherical surface with in vitro drug release up to 77.89%. The drug content was found to be 97.23%–98.89%. The suspension was found to be visually clear with pH ranging from 6 to 7. The drug entrapment was found to be from 76.37% to 97.34%. Since there was no hemolytic activity, this formulation was suitable for ophthalmic administration. The Draize test confirmed the non-irritant, non-itchy nature of formulation. The prepared formulations, such as nanoparticulate gel and suspension, were found to be significantly efficacious in experimental animals.

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