Pseudomonas aeruginosa filtrates

Ansel HC, Norred WP, Roth IL. Antimicrobial activity of dimethyl sulfoxide against Escherichia coli. Pseudomonas aeruginosa, and Bacillus megaterium. J Pharm Sci 1969 58(7) 836—839. Placencia AM, Oxborrow GS, Danielson JW. Sterility testing of fat emulsions using membrane filtration and dimethyl sulfoxide. ] Pharm Sci 1982 71(6) 704-705. 

Examples of preservatives are phenylmercuric nitrate or acetate (0.002% w/v), chlorhexidine acetate (0.01% w/v), thiomersal (0.01% w/v) and benzalkonium chloride (0.01% w/v). Chlorocresol is too toxic to the corneal epithelium, but 8-hydroxy-quinoline and thiomersal may be used in specific instances. The principal consideration in relation to antimicrobial properties is the activity of the bactericide against Pseudomonas aeruginosa, a major source of serious nosocomial eye infections. Although benzalkonium chloride is probably the most active of the recommended preservatives, it cannot always be used because of its incompatibility with many compounds commonly used to treat eye diseases, nor should it be used to preserve eye-drops containing anaesthetics. As benzalkonium chloride reacts with natural rubbers, silicone or butyl rubber teats should be substituted and products should not be stored for more than 3 months after manufacture because silicone rubber is permeable to water vapour. As with all rubber components, the rubber teat should be pre-equilibrated with the preservative before use. Thermostable eye-drops and lotions are sterilized at 121 °C for 15 minutes. For thermolabile drugs, filtration sterilization followed by aseptic filling into sterile containers is necessary. Eye-drops in plastic bottles are prepared aseptically. 

In the area of aflatoxin problems, cultures of Pseudomonas sp. have been observed to have efficacy to destroy the toxin in concentration up to 200 ppb similarly, culture filtrates of a strain of P. aeruginosa exhibited the ability to completely eliminate aflatoxin (10 pmg to nil ) through excretion of a low molecular weight protein acetylcholineesterase immobilized on polymeric membranes by gelatin entrapment [65]. 

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