A Kinetic Photometric Method For Benzalkonium Chloride Determination In Eye Drops

2018 ◽  
pp. 177-182
Author(s):  
Mykola Blazheyevskіy ◽  
Olena Koval’ska
Keyword(s):  
Correlation Coefficient ◽  
Linear Dependence ◽  
Peracetic Acid ◽  
Benzalkonium Chloride ◽  
Reaction Rate ◽  
Photometric Method ◽  
Eye Drops ◽  
Indicator Reaction ◽  
Chloride Determination

A novel sensitive kinetic photometric method for the Benzalkonium Chloride (BAC) determination has been developed. The method is based on the ability to inhibit the reaction of Acetylcholine hydrolysis by cholinesterase. The reaction rate is evaluated by the non-hydrolysed Acetylcholine residue, which is determined by the amount of Peracetic acid, produced during the interaction with the excess of H 2 O 2 . Indicator reaction is an interaction of p-phenetidine with Peracetic acid that leads to the formation of 4,4'-azoxyphenetole with λ max = 358 nm (lg ε = 4.2). The conditions affecting the reaction (reagents concentration, pH, order of addition of reagents, stability in time) have been optimized. The linear dependence has been obeyed in the range of (1.4-8.4)·10 -6 mol L -1 of BAC with correlation coefficient of 0.999. The assay LOQ (20 % of the inhibition degree) has been 1.9·10 -6 mol L -1 . The proposed method has been successfully applied to the analysis of the eye drops and has shown an accuracy and reliability of the results obtained.

scholarly journals HrcA and DnaK are important for static and continuous-flow biofilm formation and disinfectant resistance in Listeria monocytogenes

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3782-3790 ◽  
Author(s):  
Stijn van der Veen ◽  
Tjakko Abee
Keyword(s):  
Listeria Monocytogenes ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Peracetic Acid ◽  
Continuous Flow ◽  
Biofilm Formation ◽  
Benzalkonium Chloride ◽  
Wild Type ◽  
Shock Response ◽  
Disinfectant Resistance

The food-borne pathogen Listeria monocytogenes is able to form biofilms in food processing environments. Since biofilms are generally difficult to eradicate during clean-up procedures, they pose a major risk for the food industry. Stress resistance mechanisms involved in L. monocytogenes biofilm formation and disinfectant resistance have, to our knowledge, not been identified thus far. In this study, we investigated the role of hrcA, which encodes the transcriptional regulator of the class I heat-shock response, and dnaK, which encodes a class I heat-shock response chaperone protein, in static and continuous-flow biofilm formation and resistance against benzalkonium chloride and peracetic acid. Induction of both hrcA and dnaK during continuous-flow biofilm formation was observed using quantitative real-time PCR and promoter reporters. Furthermore, in-frame deletion and complementation mutants of hrcA and dnaK revealed that HrcA and DnaK are required to reach wild-type levels of both static and continuous-flow biofilms. Finally, disinfection treatments of planktonic-grown cells and suspended static and continuous-flow biofilm cells of wild-type and mutants showed that HrcA and DnaK are important for resistance against benzalkonium chloride and peracetic acid. In conclusion, our study revealed that HrcA and DnaK are important for L. monocytogenes biofilm formation and disinfectant resistance.

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.

scholarly journals MANAGERIAL EVALUATION OF THE LOGISTICS PERFORMANCE AND ITS DEPENDENCIES ON ECONOMIES IN SELECTED COUNTRIES

2020 ◽  
Vol 15 (1) ◽  
pp. 15-27
Author(s):  
Alexandra Filova ◽  
Veronika Hrda
Keyword(s):  
Correlation Coefficient ◽  
Linear Dependence ◽  
Slovak Republic ◽  
Strong Dependence ◽  
African Continent ◽  
Transport Efficiency ◽  
The World ◽  
Per Capita ◽  
Logistics Performance Index ◽  
The Individual

The objective of the paper is managerial evaluation of the level of logistics on individual continents and to find out dependence between the level of logistic systems and the level of GDP in the selected countries of the world. To evaluate logistics, we used the Logistics Performance Index and its six categories (customs clearance, infrastructure, international shipment, logistic competencies, monitoring shipment, and satisfaction). The index of gross domestic product was shown per capita and in constant U.S. dollars for 2010. The analyzed period was the years 2010, 2012, 2014, 2016, and 2018. Together, we analyzed 134 countries from five of the world’s continents. Results are provided separately for the European countries and the Slovak Republic. To find out mutual linear dependence, we used the correlation coefficient. From the results of the research, it is clear that there is a connection between the variables LPI and GDP and thus that there exists a direct linear dependence. Only in one case, that of the African continent in 2018, was the coefficient of correlation close to zero and we had to state that the variables were not linearly dependent. For most resulting values of the correlation coefficient, we found only slight linear dependence. The exception was the countries of Australia and Oceania, where a strong dependence was found for all the years in question. This kind of analysis has significance primarily on the macroeconomic level. The individual countries can investigate, evaluate, and consequently improve their respective logistic systems and services. Understanding and decomposing the components of trade and logistics performance can help countries improve freight transport efficiency and identify where international cooperation could help overcome barriers.

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.

scholarly journals Characteristics of Listeria Monocytogenes Strains Persisting in a Meat Processing Facility over a 4-Year Period

Pathogens ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 32 ◽  
Author(s):  
Andrea Stoller ◽  
Marc Stevens ◽  
Roger Stephan ◽  
Claudia Guldimann
Keyword(s):  
Listeria Monocytogenes ◽  
Genome Sequencing ◽  
Peracetic Acid ◽  
Benzalkonium Chloride ◽  
Food Production ◽  
Whole Genome ◽  
Meat Processing ◽  
Minimal Inhibitory Concentrations ◽  
Processing Facility ◽  
Young Old

Listeria monocytogenes can persist in food production facilities, resulting in serious threats to consumers due to the high mortality associated with listeriosis, especially in the very young, old and pregnant. We subtyped 124 strains of L. monocytogenes isolated from a meat processing facility in Switzerland by serotyping, multi locus sequence typing (MLST) typing and whole genome sequencing. We then analyzed their ability to form biofilms and their resistance to the disinfectants benzalkonium chloride (BC) and peracetic acid (PAA). The genotyping results of the strains showed that several clonal populations of L. monocytogenes belonging to CC9, CC204 and CC121 had persisted in this meat processing facility for at least four years. All of the strains showed biofilm forming capacity comparable to a known high biofilm forming strain. Known efflux pumps for BC were present in CC204, CC9 (brcABC) and CC121 (qacH) strains, while strains from other CC showed very low minimal inhibitory concentrations (MICs) for BC. For PAA, minimal bactericidal concentrations of 1.2–1.6% for 20 min and minimal inhibitory concentrations between 0.1 and 0.2% were observed. These values were close to or above the recommended concentration for use (0.5–1%), suggesting that PAA might be ineffective at controlling L. monocytogenes in this and potentially other meat processing facilities.

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