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An o-phthalaldehyde disinfectant (CidexOPA) is a high-level disinfectant for clinical disinfection, which is mainly used for soaking disinfection of medical devices, especially for endoscopic disinfection. Compared with other disinfectants currently used, it has the characteristics of wide sterilization spectrum, low concentration, short sterilization time, low irritation and low corrosion, and is gradually widely used in clinical practice. In this study, the effects of the drug on acute oral toxicity and micronucleus formation of bone marrow polychromatic erythrocytes in mice were detected, and compared with the commonly used endoscopic disinfectant glutaraldehyde to evaluate the safety of its clinical application. 1 Materials and Methods 1.1 Materials CidexOPA High-level Disinfectant (Johnson & Johnson Company) is a light blue transparent liquid whose main component is phthalaldehyde (ortho-phthalaldehyde,OPA), with a positive phthalaldehyde content of 5500mg/L and a pH of 7.45. ICR mice [license number SCXK(J)2007- 0003] were purchased from the experimental animal center of Bethune medical college of Jilin university. the animals were kept in an ordinary animal room with a temperature of 22 ~ c and a relative humidity of 50%. 1.2 Method 1.2.1 Acute oral toxicity test in mice 5O mice of 18~22g were selected and randomly divided into 5 groups, half male and half female in each group. Before the test, they were fasted for 8 hours and could not help drinking water. The dose of CidexOPA stock solution was 4.5, 5.0, 5.5, 6.0 and 6.5 g/kg (body weight), respectively, and 0.2mL/lOg was given by one-time intragastric administration. After the administration of normal feeding, continuous observation for 14 days, observe and compare the poisoning performance and death of mice in each group. 1.2.2 Mouse bone marrow polychromatic erythrocyte micronucleus test 60 mice of 25 - 30g were selected and randomly divided into 6 groups, each group was half male and half female, fasting for 4 hours before the experiment, and water was not stopped. The CidexOPA experimental group was given 500, 2000 and 5000 mg/kg (body weight), the positive control group was given cyclophosphamide 40 mg/kg (body weight), and the negative control group was given the same amount of distilled water. The glutaraldehyde group was given 20 L glutaraldehyde 5000 mg/kg (body weight). The method of oral gavage for 30h was adopted, I .e. the animal was killed by cervical vertebra decondition 24h after the first exposure, 6h after the second administration, calf serum was used to flush the femoral bone marrow cavity, bone marrow flushing fluid smear was taken, and the number of micronucleated cells contained in 1000 bone marrow polychromatic erythrocytes (PCE) was counted under a microscope after formaldehyde fixation and Giemsa staining. The number of normal red blood cells (NCE) was observed, and the ratio of PCE/NCE was calculated. During the experiment, the feeding, activity times and mental state of mice in each group were observed and compared. 2 Results 2.1 mice acute oral toxicity test results CidexOPA according to the dose of the administration of mice gavage, each dose group of mice had no adverse performance, observation of 14 days, the process of each group of mice by hair luster, diet, normal activities, good mental state, weight loss, the whole process did not see the death of mice. The median lethal dose of mice was> 6500 mg/kg body weight. The micronucleus rate of polychromatic erythrocytes in bone marrow of 2.2 mice is shown in Table 1. The micronucleus rate of polychromatic erythrocytes in bone marrow of mice (‰) is transformed by square root and analyzed by variance. It is CidexOPA that there is no significant difference between the micronucleus rate of polychromatic erythrocytes in each dose group and the negative control group (P>0.05), and there is no significant difference between the CidexOPA group and the glutaraldehyde group (P>0.05), the difference between the positive control group and the negative control group was significant (P<0.01), and the results showed that the three dose CidexOPA did not cause an increase in the incidence of micronuclei in bone marrow polychromatic erythrocytes in mice. The PCE/NCE ratio was greater than 0.1, which proved that the experimental dose of each group had no obvious inhibitory effect on bone marrow, and the experimental dose of CidexOPA had no damaging effect on the chromosome of mouse bone marrow polychromatic erythrocytes. During the experiment, the mice in each group were CidexOPA with luster, normal diet and activities, and good spirits. The mice in the glutaraldehyde group had shiny hair, normal diet, reduced activity frequency, and acceptable spirit. In the cyclophosphamide group, the hair was dull, the diet was fair, the frequency and range of activities were significantly reduced, and the spirit was poor.

3 Discussion CidexOPA was first applied to endoscope disinfection in Canada in 1994 and passed FDA certification as a new type of high-efficiency chemical disinfectant in 1999. It achieved disinfection and sterilization through cross-linking, human membrane and other mechanisms]. According to the 2002 edition of the Ministry of Health "Disinfection Technical Specification" chemical substance acute toxicity grading standard evaluation regulations, LD.> 5000 mg/kg (body weight) is the actual non-toxic, this experiment proves that ci- dexOPA is the actual non-toxic level. In this experiment, each dose group had no damage effect on the chromosome of mouse bone marrow polychromatic erythrocytes, which confirmed that the CidexOPA did not have mutagenic effect under the experimental conditions. Although there was no difference between PCE and glutaraldehyde in the CidexOPA group, glutaraldehyde itself has inherent toxicity and has potential health hazards to medical staff and patients. In the actual endoscopic decontamination, glutaraldehyde in order to achieve the standard of disinfection, it takes a long time to soak. For example, 2100mg,/L of OPA acts on the pollution of 10. The average killing time of cfu/ml M. bovis was 6min, while 1.5% glutaraldehyde required 30min J. CidexOPA as a new disinfectant with high efficiency, economy and safety], has high clinical application value. References [1] Chen Jing, Xu Nengfeng. Disinfection effect of o-phthalaldehyde and its mechanism [J]. Foreign Medicine (Epidemiology and Infectious Diseases Branch),2004,31(2):121-124. (23 Li 0.6 billion. A new chemical sterilization agent-o-phthalaldehyde [J]. Chinese Journal of Hospital Infection, 2003,13(4):397-398. [3] Li Yang, Liu Feng, Tian Huawen. Comparison and economic evaluation of the durability of ortho-phthalaldehyde and glutaraldehyde under machine washing and disinfection conditions [J]. Chinese Journal of Digestive Endoscopy, 2010,27 (2):77-79.