| BackgroundPeriodontitis is a kind of familiar and multiple infectious destructive disease which is one of the primary cause of the loss of adult teeth. It has been proved that the bacterium and it's productions in the dental plaque are the imperative initiation factor to initiation periodontal disease,and others local factors and the defense reaction of host have important influences,too.The treatment of periodontal disease should be combined therapy,the antibacterials are effective assistant ways to it. Systemic antibacterials can inhibit latent pathogenic bacteria invading periodontal tissues or other parts in buccal cavity(such as amygdale , dorsum linguae). While, even if given systemic flushing dose antibacterials, drugs still concentrated in blood serum. Patients were requested to administer repeatedly, which will cause dysbacteria, increasing adverse reaction, weak compliance and so on. Local antibacterials therapy can improve local effective drug concentration, and can achieve 10～100 times than systemic antibacterials. Meanwhile it can decrease adverse reaction and chemical sproof. Local slow-release praeparatum overcome the shortcomings of systemic or local administration. It can reduce the dosage of medicine, prolong the drug action, avoid the phenomenon of the peak valley of concentration in blood and decrease the frequency of administration.ObjectiveIn the study, first of all, to establish experimental periodontitis animal model similar to periodontitis of mankind in SD rats. To seek a kind of method which can be used to establish experimental periodontitis animal model more reasonable. Then to determine the dynamic release characteristic of ornidazole and pefloxacin from the sustained-release periodontal suppository of ornidazole and pefloxacin by high-performance liquid chromatography(HPLC) in vitro, this work is to offer experimental theory for determining the dynamic release characteristic in vivo. To determine the dynamic release characteristic of ornidazole and pefloxacin from the sustained-release periodontal suppository of ornidazole and pefloxacin by high-performance liquid chromatography (HPLC) in animal model. All of those works are to offer experimental theory for the clinic application.Materials and Methods1. Choosing 36 SD rats (12 months of age) by half female and half male, body masses of these rats are about 220±20 g.These SD rats were randomly divided into 3 groups ,and there were 12 rats in every group which were breeded separ. First group is normal group (N): the rats in which is anesthetized by intraperitoneal injection of 3% embutal and provided with rout bait vessel and drink. In the second group(P1): the rats after anesthetized in the same method as the first group the gingiva of animals was undermined and the animals were given steel-wire ligatures around the right first maxillary molars and provided with high glucose food and drink. In the third group(P2): the rats after were ligated for 1 week, P2 was inoculated with P.gingivalis in periodontal pocket every other day, and above-mentioned method were performed by five times in all. To assess the best method of the establishment of experimental animal model of periodontitis in SD rats.2. Detecting the dynamic release characteristic of ornidazole and pefloxacin from the sustained-release periodontal suppository of ornidazole and pefloxacin in vitro: in the environment of constant temperature at 37℃and degassing depurated water served as dissolved mediator, 5 pieces of suppository which are choosed randomly was put in beaker in which containing 5ml degassing depurated water, and the solution was stired every other 10 minutes, sampled at 0.5,1,2,3,4,5,6,7,8,9,10,11,13,15,18,24 h respectively. 200μl sample was taked out of and at the same time 200μl dissolved mediator was made up for. After the score of peak area of ornidazole and pefloxacin was detected and recorded by HPLC and calculated cumulative release percentage of both ingredients. To assess the characteristic of releasing of sustained-release periodontal suppository of ornidazole and pefloxacin in Vitro.3. Detecting the dynamic release characteristic of ornidazole and pefloxacin from the sustained-release periodontal suppository of ornidazole and pefloxacin in vivo:36 SD rats which had been accomplished establishment of experimental animal model of periodontitis were randomly divided into 12 groups ,and there are 3 rats in every group; 36 pieces of periodontal suppository which having been precisely weight, weight of each which was about 9 mg ,was set into periodontal pocket of SD rats above-mentioned in the way of one piece into one rat. Every group of rats was put to death by 0.5,1,2,3,5,7,10,14,18,24,36,48 hours by turns. Periodontal tissue of each rat was cut and put into Bp tube in which internal standard and Colonial spirit was added, and the volume of the content of Bp tube was defined to 3 ml. The content was broken into pieces by hypersound equipment and was centrifuged,then the clear supernatant liquid which would be served as introduction was extracted. To assess the characteristic of releasing of sustained-release periodontal suppository of ornidazole and pefloxacin in the periodontal pocket of SD rats.Results1. At week 8, food and drinks of the rats in group N are more better, their body weight to increase gradually and not to find symptoms of periodontitis. At week 4, histological examination showed symptoms of periodontitis in two experimetal groups ,but more significant individual difference in group P1 than group P2. At week 8,histological examination showed deep periodontal pockets and alveolar bone loss in two experimental groups. Estabilshing experimental expiodontitis animal model of two experimental groups was more succeeded and there was no significant individual difference in two experimental groups by the analysis of statistics.2. Detecting the dynamic release characteristic of ornidazole and pefloxacin from the sustained-release periodontal suppository of ornidazole and pefloxacin in vitro: cumulative release percent of ornidazole was 9.08% in half an hour, 59.50% in 5 hours and 98.30% in 13 hours; cumulative release percent of pefloxacin was 15.26% in half an hour, 45.00% in 5 hours and 96.01% in 13 hours.3. Detecting the dynamic release characteristic of ornidazole and pefloxacin from the sustained-release periodontal suppository of ornidazole and pefloxacin in vivo: ornidazole and pefloxacin from the sustained-release periodontal suppository of ornidazole and pefloxacin was released sustainedly in the periodontal pocket of rats, cumulative release percent of ornidazole was 71.7% in 24 hours and 87.2% in 48 hours; cumulative release percent of pefloxacin was 62.5% in 24 hours and 88.1% in 48 hours.Conclusions1. The rats in two experimental groups can display the development of periodontitis of mankind better in 8 weeks.2. The experiment in vitro showed the sustained-release periodontal suppository can release drug in 12 hours gradually, and it corresponed the regular of"Pharmacopeia"to local sustained-release preparation.3. The experiment in vivo showed the sustained-release periodontal suppository was released sustainedly in the periodontal pocket of rats, it still to remain bacteriostatic concentration after 48 hours.
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