Study On The Manufacture And Disinfection Of Compound Ortho-phthalaldehyde

【Objective】To confect a kind of compound ortho-phthalaldehyde disinfectant byorthogonal tests for improvement of killing Bacillus subtilis var.niger byortho-phthalaldehyde, and evaluate the stability, pH influential factor ofcompound ortho-phthalaldehyde, and observe germicidal efficacies, toxicity anddisinfectant mechanism of compound ortho-phthalaldehyde.【Methods】1 Experimental methodCompound ortho-phthalaldehyde included ortho-phthalaldehyde(OPA) andbromogeramine ,confected according to the orthogonal testing table L9(34) andexamined the different germicidal efficacies against Bacillus subtilis var.niger,then the optimal prescription of compound ortho-phthalaldehyde was screenedout. The stability test of the chosen compound ortho-phthalaldehyde wasconducted by methods of accelerated aging. Neutralization tests, tests of pHinfluential factor, suspension quantitative germicidal tests and continuous usingstability tests were respectively conducted by compound ortho-phthalaldehydeagainst Bacillus subtilis var.niger, Staphylococcus aureus, Escherichia coli,Pseudomonas aeruginosa and Candida albicans. The toxicology tests ofcompound ortho-phthalaldehyde were examined by methods of acute oraltoxicity test of mice and micronucleus of mouse marrow polychromaticerythrocyte. The disinfectant mechanism of compound ortho-phthalaldehyde wasinvestigated by methods of observing the ultra structure changes of Bacillussubtilis var.niger killed by compound ortho-phthalaldehyde.2 Statistic methods The bacterial count alive of experiment groups and control groups wastransformed by logarithm, and the logarithm reduction was used to represent thegermicidal efficacy. The univariate ANOVA and repeated measure ANOVA wererespectively used to deal with results of the orthogonal tests and compare thegermicidal efficacy of compound ortho-phthalaldehyde by SPSS12.0 forWindows. The Poisson-test was used to compare the rate of polychromaticerythrocyte among experiment groups, positive groups and negative groups.【Results】1 The orthogonal tests of screening out prescriptions of compoundortho-phthalaldehyde The variance analysis for results of orthogonal tests suggested thatortho-phthalaldehyde could cooperate with bromogeramine against Bacillussubtilis var.niger. The combination of 8000mg/L ortho-phthalaldehyde and4000mg/L bromogeramine was screening out according to the optimal efficacy ofkilling Bacillus subtilis var.niger. The second was the combination of 5000mg/Lortho-phthalaldehyde and 4000mg/L bromogeramine. But considering thesolubility and price for ortho-phthalaldehyde, the combination of5000mg/L ortho-phthalaldehyde and 4000mg/L bromogeramine was finallychosen, and the efficacy of killing Bacillus subtilis var.niger would beenimproved by adjusting pH value of the disinfectant solution.2 The Stability of compound ortho-phthalaldehyde After being stored in 54℃incubator for 14 days, the available content rateof ortho-phthalaldehyde decreased by 2.03%.3 Study on the germicidal efficacy of compound ortho-phthalaldehyde3.1 Tests of pH influential factor When 5000mg/L OPA in the compound ortho-phthalaldehyde solutionagainst Bacillus subtilis var.niger had been for 60 minutes at different pH valuesof 5.3, 7.0, 8.3, the logarithm mean reduction was respectively 0.20,3.86,6.73.3.2 Tests of compound ortho-phthalaldehyde against bacteria and Candidaalbicans When 50mg/L,25mg/L,12.5mg/L OPA in the compoundortho-phthalaldehyde solution had been for 3 minutes, the logarithm meanreduction was respectively 6.34, 3.76, 0.79 against Staphylococcus aureus,respectively 5.56, 3.22, 0.44 against Pseudomonas aeruginosa, respectively 6.37,2.08, 1.73 against Escherichia coli, respectively 7.24, 4.28, 2.04 against Candidaalbicans.3.3 The stability tests of compound ortho-phthalaldehyde used continuously When the medical instruments had been soaked into the solution of5000mg/L OPA in the compound ortho-phthalaldehyde solution for 21 daysunder the room temperature(15±2℃), the disinfectant solution had still beeneffective against Bacillus subtilis var.niger in the simulated germicidal tests forthe medical instruments.4 The toxicology tests of compound ortho-phthalaldehyde The mouse oral LD50 of compound ortho-phthalaldehyde was>5000mg/(kg·bw) in the acute toxic tests. The rate of PCE with micronucleusinduced by three doses of compound ortho-phthalaldehyde showed no significantdifference from the negative control group (p>0.05, respectively).5 The observation of ultra structure changes of Bacillus subtilis var.nigerkilled by compound ortho-phthalaldehyde After Bacillus subtilis var.niger had been exposed for 30 minutes under5000mg/L OPA in the compound ortho-phthalaldehyde solution, the changes ofthe ultra structure showed that the shape was anamorphic, the electron densityand thickness of the coat was unequal, the transmission area of the cortex wasenlarged or blurred, and the core leaned to one side or appeared the transmissionarea.【conclusions】 Under 8.3 of pH value, the chosen compound ortho-phthalaldehydedisinfectant by the orthogonal tests has the quick and high germicidal activity,and effectively kills Staphylococcus aureus, Escherichia coli, Pseudomonasaeruginosa, Candida albicans and Bacillus subtilis var.niger. The compoundortho-phthalaldehyde disinfectant can continuously sterilize the medicalinstruments for 21 days and be stored airtight at the room temperature for 1 year.The compound ortho-phthalaldehyde is a disinfector with no toxicity and nochromosome impairment. The outer coat of Bacillus subtilis var.niger wasimpaired and the cytoplasm content was leaked under exposure of compoundortho-phthalaldehyde, suggested that the cell structure was destroyed.