Effects of Benzalkonium Chloride on Pilocarpine-induced Opacity in Porcine Isolated Corneas

1993 ◽  
Vol 21 (3) ◽  
pp. 372-383
Author(s):  
Haruyoshi Igarashi ◽  
Yasunaga Katsuta ◽  
Kayoko Sawa ◽  
Yuu Chiba ◽  
Michio Kozima ◽  
...  
Keyword(s):  
Benzalkonium Chloride ◽  
High Performance ◽  
Physiological Saline ◽  
Experimental Period ◽  
Eye Drops ◽  
In Vitro Test ◽  
Endothelial Surface ◽  
Descemet's Membrane ◽  
Descemet’S Membrane

The incubation of isolated porcine corneas (intact, with the epithelium or endothelium plus Descemet's membrane removed, or with both the epithelium and endothelium plus Descemet's membrane removed) with solutions of pilocarpine HCl (5 X 10 4M or 5 x 10-3M) for four hours caused very little increase in opacity when compared with corneas incubated with physiological saline. However, at a higher concentration (5 x 10-2M), the application of pilocarpine to the endothelial surface, or to both the epithelial and endothelial surfaces of intact corneas, caused an obvious increase in opacity. The addition of the preservative benzalkonium chloride (BC; 0.005%) to pilocarpine solutions caused an increase in opacity, but in no circumstances did this appear to be other than an additive effect, since incubation with BC alone had an opacifying effect. This in vitro test confirms that pilocarpine is a safe drug for application as eye-drops. Studies using high performance liquid chromatography showed that BC increased the amount of pilocarpine passing through the cornea from the epithelial to the endothelial surface. A small amount of BC also passed through the cornea over the 4-hour experimental period.

scholarly journals Benzalkonium chloride corneal toxicity post-cataract surgery

2020 ◽  
Vol 17 (1) ◽  
pp. 56-60
Author(s):  
Keith Ong ◽  
Leonard Ong
Keyword(s):  
Cataract Surgery ◽  
Benzalkonium Chloride ◽  
Corneal Stroma ◽  
Eye Drops ◽  
Descemet's Membrane ◽  
Corneal Toxicity ◽  
Descemet’S Membrane ◽  
Free Steroid

Two patients with presumed benzalkonium chloride (BAK) corneal toxicity after routine cataract surgery are presented. Patient 1 had corneal stroma and Descemet’s membrane folds. Patient 2 had moderate superficial punctate epithelial erosions (SPEE). They were on Chlorsig, Maxidex, and Acular eye drops tds postoperatively. The corneas of these two patients improved when BAK was removed or minimized from the postoperative eye drop regimen. Two vials of 1 ml dexamethasone 4mg/ml for injection were added to Chlorsig 10 ml bottle to substitute for Maxidex eye drops. BAK toxicity should be suspected when the cornea is not as clear as expected postoperatively. A practical way to eliminate BAK from postoperative eye drops is described, and would be useful until pharmaceuticals mass-produce BAK-free steroid eye drops economically.

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

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.

scholarly journals COMPARISON OF PRESERVATIVES EFFICACY OF BENZALKONIUM CHLORIDE, THIMEROSAL AND BENZYL ALCOHOL IN EYE DROP PRODUCTS CONTAINING CHLORAMPHENICOL

2020 ◽  
pp. 100-105
Author(s):  
SRI AGUNG FITRI KUSUMA ◽  
MARLINE ABDASSAH ◽  
FITASARY MARYATI
Keyword(s):  
Benzyl Alcohol ◽  
Benzalkonium Chloride ◽  
Room Temperature ◽  
Storage Time ◽  
Storage Period ◽  
Diffusion Method ◽  
Eye Drops ◽  
Inhibition Zones ◽  
In Vitro Stability

Objective: The aim of this study was to compare the preservative efficacy of benzalkonium chloride, thimerosal and benzyl alcohol in eye drops formulation containing chloramphenicol as the active agents for producing the sterile and effective eye drops.Methods: The efficacy of preservatives was assayed by evaluating the physical appearance, pH stability, sterility and the antibacterial effectivity of the formulated eye drops. Each of 0.5% chloramphenicol was formulated with different preservatives of benzalkonium chloride, thimerosal and benzyl alcohol at its recommended concentration, 0.01%; 0.01% and 1%, respectively. The in vitro stability was examined periodically for the eye drops formulation stored at room temperature during the 28-day period. The effectiveness of the antibacterial effect of chloramphenicol in eye drops was assayed by using the agar diffusion method against Escherichia coli and evaluated for the diameter of inhibition zones. Result: The clarity of the eye drops formula produced clear solutions. The eye drops formula exhibited relatively stabile on pH. All the formulated eye drops were sterile during the storage time. The appropriate of the sterilization method was thought to contribute to the sterility of eye drops which did not contain preservatives. In addition, it was assumed that the pre-reaction of chloramphenicol in inhibiting the contaminants in the eye drop may occur during the storage time. This hypothesis was confirmed by the inhibitory diameter stability produced by the eye drop formulas containing preservatives compared to that of not. The decrease in inhibition diameter occurred during the storage period (28 d) of each formula was as follows: F0 (51.58%), F1 (35.76%), F2 (31.86%), and F3 (35.35%). The best stability based on the antibacterial activity of the chloramphenicol eye drops was produced by F2 which used 0.01% thimerosal as its preservative. The differences in inhibition diameter were significantly influenced by the presence and the type of preservatives. Conclusion: 0.01% thimerosal indicated the best improvement on the efficacy of 0.5% chloramphenicol eye drop.

STUDIES ON PROTEIN METABOLISM OF THE CORNEA: 1. THE DISTRIBUTION OF NITROGENOUS SOLIDS IN RABBIT CORNEAS

1963 ◽  
Vol 41 (4) ◽  
pp. 1005-1011 ◽  
Author(s):  
R. C. French ◽  
Z. Duma
Keyword(s):  
Nitrogen Content ◽  
Protein Metabolism ◽  
Physiological Saline ◽  
Dry Weight ◽  
Weight Basis ◽  
Rabbit Cornea ◽  
Corneal Layer ◽  
Descemet's Membrane ◽  
Descemet’S Membrane ◽  
Cornea Endothelium

The normal rabbit cornea was found to contain an average of 22.7% solids (77.3% moisture), nitrogen comprising 14.7% of the dry weight. On a dry weight basis the cornea was composed of 10% as epithelium, 87% as stroma, and 3% as endothelium plus Descemet's membrane. The solid and nitrogen content of the stroma was nearly identical with that of the whole cornea. Endothelium plus Descemet's membrane and epithelium layers were relatively low in nitrogen content (10 and 12% of the dry weight, respectively) while the epithelium was relatively high in solids (30%). The partition of nitrogen, as protein and nonprotein, soluble or insoluble in physiological saline, was estimated for each corneal layer.

scholarly journals Benzalkonium Chloride-Preserved Anti-Glaucomatous Eye Drops and Their Effect on Human Conjunctival Goblet Cells in vitro

2021 ◽  
pp. 69-75
Author(s):  
Anne Hedengran ◽  
Xenia Begun ◽  
Olivia Müllertz ◽  
Zaynab Mouhammad ◽  
Rupali Vohra ◽  
...  
Keyword(s):  
Cell Viability ◽  
Cell Survival ◽  
Goblet Cell ◽  
Benzalkonium Chloride ◽  
Goblet Cells ◽  
Eye Drops ◽  
Dependent Manner ◽  
The Impact ◽  
Conjunctival Goblet Cells

<b><i>Introduction:</i></b> Most intraocular pressure (IOP)-lowering eye drops are preserved with benzalkonium chloride (BAK). This can increase side effects and decrease adherence. Particularly, damage to the mucin-producing conjunctival goblet cells may be an issue due to instability of the tear film. We aimed to investigate the effect of IOP-lowering eye drops preserved with BAK on cultured human conjunctival goblet cells. <b><i>Methods:</i></b> Eye drops Brimonidine Tartrate Teva (BT) with 0.005% BAK, Dorzolamide Stada (DS) with 0.0075% BAK, Optimol<sup>®</sup> (OP) with 0.01% BAK, and Latanoprost Teva (LT) with 0.02% BAK were included. Human primary cultured goblet cell survival was evaluated using a lactate dehydrogenase assay on human goblet cells after treatment for 30 min and 6 h with the different anti-glaucoma drug formulations. <b><i>Results:</i></b> All eye drops examined, except BT, reduced goblet cell survival. The impact of eye drops on goblet cell viability was correlated with the time of exposure as well as to the concentration of BAK. After 30 min of exposure, cell viability was 93% for BT (0.005% BAK; <i>p</i> = 0.93), 71% for DS (0.0075% BAK; <i>p</i> = 0.067), 70% for OP (0.01% BAK; <i>p</i> = 0.054), and 69% for LT (0.02% BAK; <i>p</i> = 0.022), and exposure for 6 h reduced cell survival to 74% for BT (<i>p</i> = 0.217), 52% for DS (<i>p</i> = 0.011), 34% for OP (<i>p</i> = 0.017), and 31% for LT (<i>p</i> = 0.0007). <b><i>Conclusion:</i></b> LT, OP, and DS reduced human goblet cell survival in a time-dependent manner. BT did not affect goblet cell survival. Cell survival was correlated with the BAK concentration in the eye drops making 0.02% BAK-preserved LT most toxic and 0.005% BAK-preserved BT least toxic. Based on the present study, decreasing BAK in eye drops for chronic use seems important to reduce damage to the goblet cells. However, future studies are needed to further explore this finding.

scholarly journals Allergen Extraction: Factors Influencing Immunogenicity and Sensitivity of Immunoassays

2021 ◽  
Author(s):  
João Ricardo Almeida Soares ◽  
Airton Pereira e SIlva ◽  
Isabelle Guimarães ◽  
Ana Luisa Oliveira ◽  
Claudia Regina Faccini ◽  
...  
Keyword(s):  
Social Impact ◽  
Protein Extraction ◽  
Protein Profile ◽  
Physiological Saline ◽  
Extraction Methods ◽  
The Body ◽  
Mouse Strains ◽  
In Vitro Test

Because of the high social impact of Food allergy, it is of great importance to correctly diagnose this disease using reliable tests. Knowledge of the allergenicity properties of proteins, how they react in the body and in diagnostic tests is necessary to adequately assess the potential immunogenicity of both natural foods and those produced through biotechnological processes. Thus, our aim was to analyze the factors that influence the protein extraction of foods in terms of, immunogenicity and immunoassays sensitivity. Peanut proteins were extracted using four distinct extraction buffers (physiological saline, tris buffer, borate buffer with and without β-mercaptoethanol), the protein concentration was determined by the Lowry method and polyacrylamide electrophoresis (SDS-PAGE) was used to compare the protein profile of each extract. The immunogenicity of each extract was verified by sensitizing two mouse strains (Balb/c and C57/BL6) with solution containing 100μg of the extracted proteins and determined by ELISA. Results show that extraction with the distinct buffers resulted in protein solutions with different yields and profiles. The immunogenicity of the different extracts also demonstrated distinct patterns that varied depending on the extraction methods, mouse strain and in-vitro test. Immunoreactivity varied in accordance to the protein extract used to coat the microtitration plates. In conclusion, the protein profile in the extracts is critically influenced by the salt composition and pH of the extraction buffers, this in turn influences both in vivo immunogenicity and in vitro immunoreactivity.

STUDIES ON PROTEIN METABOLISM OF THE CORNEA: 1. THE DISTRIBUTION OF NITROGENOUS SOLIDS IN RABBIT CORNEAS

1963 ◽  
Vol 41 (1) ◽  
pp. 1005-1011
Author(s):  
R. C. French ◽  
Z. Duma
Keyword(s):  
Nitrogen Content ◽  
Protein Metabolism ◽  
Physiological Saline ◽  
Dry Weight ◽  
Weight Basis ◽  
Rabbit Cornea ◽  
Corneal Layer ◽  
Descemet's Membrane ◽  
Descemet’S Membrane ◽  
Cornea Endothelium

The normal rabbit cornea was found to contain an average of 22.7% solids (77.3% moisture), nitrogen comprising 14.7% of the dry weight. On a dry weight basis the cornea was composed of 10% as epithelium, 87% as stroma, and 3% as endothelium plus Descemet's membrane. The solid and nitrogen content of the stroma was nearly identical with that of the whole cornea. Endothelium plus Descemet's membrane and epithelium layers were relatively low in nitrogen content (10 and 12% of the dry weight, respectively) while the epithelium was relatively high in solids (30%). The partition of nitrogen, as protein and nonprotein, soluble or insoluble in physiological saline, was estimated for each corneal layer.

Carbachol HCl-Induced Opacity of Porcine Isolated Cornea

1989 ◽  
Vol 16 (4) ◽  
pp. 322-330
Author(s):  
Haruyoshi Igarashi ◽  
Yasumaja Katsuta ◽  
Hidefumi Matsuno ◽  
Yoshiharu Nakazato ◽  
Tohru Kawasaki
Keyword(s):  
Topical Application ◽  
Benzalkonium Chloride ◽  
Corneal Opacity ◽  
Wetting Agent ◽  
Great Care ◽  
Epithelial Surface ◽  
In Vitro Development ◽  
Endothelial Surface ◽  
Vitro Development

The in vitro development of porcine corneal opacity induced by carbachol was monitored using a simple, specially constructed opacitometer. Corneas were used intact, without epithelium, or without endothelium, or stroma only. Solutions of carbachol were applied to both surfaces, to the epithelial surface only or to the endothelial surface only. When carbachol was applied either to both surfaces or to the epithelial surface only, there was a significant increase in opacity compared with controls in the order: both epithelium and endothelium removed>epithelium removed>endothelium removed>intact. However, when applied to the endothelial surface only of intact and endothelium-removed corneas, carbachol caused an opacity comparable to control values. This confirms that the drug is safe for use as a topical application in the eye. However, the opacity which develops in corneas in response to benzalkonium chloride indicates that great care must be taken in determining the optimal concentration to use as a “wetting agent”.

The Opacifying Effects of Carteolol HCl and Benzalkonium Chloride on Porcine Isolated Corneas

1991 ◽  
Vol 19 (3) ◽  
pp. 344-351
Author(s):  
Haruyoshi Igarashi ◽  
Yasunaga Katsuta ◽  
Yoshiharu Nakazato ◽  
Tohru Kawasaki
Keyword(s):  
Benzalkonium Chloride ◽  
Modes Of Action ◽  
Descemet's Membrane ◽  
Descemet’S Membrane

Porcine isolated corneas (intact, with the epithelium or endothelium plus Descemet's membrane or both epithelium and endothelium plus Descemet's membrane removed) have been incubated with solutions of carteolol HCl (5 x 10-4 M-5 x 10 2M), or solutions of benzalkonium chloride (0.005%–0.05%), or solutions of carteolol (5 x 10 4M-5 x 10 2M) plus benzalkonium chloride (0.005%). Concentration-dependent opacities developed in corneas with both compounds, but whereas the effect of carteolol seems to involve mainly the endothelium, the effect of benzalkonium seems to involve mainly the epithelium. Possible modes of action of the two compounds are discussed.

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