| In recent years, the extensive use of chemical insecticide presents several serious problems including drug residue, drug-resistance and enviroment damage. These problems have lead to research efforts to develop safer and efficient alternatives. Botanical acaricides have been considered as a potential alternative source to existing insecticide, because some botanical acaricides are not easily to produce drug-resistance, and have low drug residue, few harmful effects on environment. The eugenol microcapsules were prepared by monophase coagulation. The optimal method in preparation of eugenol microcapsules was established by orthogonal design after the influence factors were analyzed and the detecting method of the content of eugenol in the microcapsules by high performance liquid chromatography(HPLC) was established as well as its stability and clinical pharmacodynamics were studied. The results were as follows:1. The optimal parameters were of eugenol microcapsule were the concentration of alginate sodium was 2.5%, the weight ratio of alginate sodium to eugenol was 1:1, that the quantity of tween-80 was 0.3%, and the concentration of CaCl2 was 2%. The microcapsules are mostly spherical shape with smooth surface, uniform size, and its average diameter is 54μm, encapsulation rate is 87.6%. The voltile rate of eugenol was 42.4%, but the volatile rate of eugenol microcapsule was 13.4%(P<0.01)after heating 10h at 100℃.2.The established method of detecting eugenol in the eugenol microcapsules: the effective ingredient of eugenol microcapsule was detected by external reference method of HPLC. The high performance liquid chromatographic conditions were as followed: waters symmetry with a C18 column (250mm×4.6mm, 5μm) as stationary phase and methanol-water (65:35) as mobile phase; the detection wavelength at 280nm; flowing rate in 0.8ml/min; The calibration curves was a good linearity in the range of 0.00493～0.096mg/mL for eugenol at 280.0nm, the average recovery rate was 98.02% with RSD 0.42%. The content of eugenol in the preparated eugenol microcapsule was 878.7mg/g (n=3).3. Stability experiment: The eugenol microcapsule appearance was no obvious changes and the content of eugenol decreased by 3.11 percent and 3.50 percent under the conditions of high temperature(60℃) or high humidity (relative humidity of 90% ) for 10d. The eugenol microcapsule became reddish-brown and the content of eugenol decreased by 6.57% as it was exposured to strong light (4500 lx±500lx) for 10d. The results showed that the microcapsules were steady under the conditions of the high temperature and high humidity and sensitive to the light. Under the conditions of temperature of 40℃and relative humidity of 75% for 3 months, the microcapsule appearance was no obvious changes, and the eugenol content of three batches decreased by 2.68%, 2.79%, 2.71%, respectively, which were in line with requirements of agents. The classical constant temperature test indicated that the change of eugenol content in the microcapsules was accorded with Arrhenius index law, and the predicting term of validity was two years as keeping in dark place at room temperature(25℃).4. Pharmacodynamics experiment: Acaricidal effects of the eugenol microcapsules to parasites in intestine of rabbits were investigated. The results indicated that the higher dosage group of eugenol microcapsules(18.26mg/kg), the lower dosage group of eugenol microcapsules(9.13mg/kg), the control group of eugenol(7.5mg/kg) and robenidine(50mg/kg)had a same helminthic effects. If the eugenol microcapsules were applied to treat the disease of the intestinal parasites of rabbits, the higher dosage(18.26mg/kg) will be needed within 24h, and then the lower dosage(9.13mg/kg)will be merely given after 24h, of which the effects were the same as eugenol and robenidine.
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