| With the rapid development of animal husbandry,animal parasitic diseases have already become one of the important factors that hindering the development of domestic animal husbandry.Especially for grazing animals such as cattle and sheep,they are often disturbed by all kinds of nematodes,resulting in animal emaciation,low feed utilization rate,and great economic losses to cattle and sheep husbandry.However,most antibiotics on the market have developed resistance,so it is particularly important to develop a new prescription with a simple,convenient and efficient dosage form.In this experiment,ivermectin and levamisole were mixed into a dry suspension.The preparation and investigation of compound ivermectin dry suspension were completed by establishing in vitro assay method of ivermectin and levamisole,single factor and orthogonal test to screen the optimal prescription,stability test and pharmacokinetic study in rats.This study by high performance liquid chromatography(HPLC)method to establish an in vitro of ivermectin content determination method,the chromatographic conditions to choose mobile phase: acetonitrile-methanol-water(55:35:12,v/v/v),detection wavelength:254 nm,column temperature:30 ?,velocity:1 m L/min,the sample amount:20 ?L,with the concentration of ivermectin C as the abscissa,peak area A as the ordinate,10-150 ng/m L range of linear regression,the regression equation is A= 23569 + 1464.6 c,= 0.99783,design 80 ?g/m L(low),100 ?g/m L(middle),and 120 ?g/m L(high)respectively sample 3 times of test sample solution for ivermectin sample recovery rate determination,RSD value results were 1.26%,1.25%,1.84%,The control solutions of 10 ?g/m L,50 ?g/m L,and 100 ?g/m L were prepared,respectively.The precision of ivermectin was determined for 5 times in the same day and for 5 consecutive days,and the RSD value results were 1.61%,1.46%,0.89%.As can be seen from the above experiments,this method has the advantages of strong specificity,high accuracy and good repeatability,and can be used for the determination of ivermectin content in vitro and the stability experiment.The RSD values of sample recovery and precision were less than 2%,which met the methodological requirements.In this study,the non-aqueous solution potentiometric titration method was used to determine the content of levamisole hydrochloride.The equation was A=41.9c+11.2,R2=0.9999.The designed sample solution of 0.67 mg/m L(low),0.83 mg/m L(medium),and 1 mg/m L(high)was injected three times for the determination of the recovery rate of levamisole addition.The RSD value results were 1.63%,1.93%,1.82%.The reference solutions of 0.5 mg/m L,1.0 mg/m L and1.5 mg/m L were respectively injected five times on the same day and tested at the same time for 5consecutive days.The precision of levamisole was determined,and the RSD value results were0.04%,0.06%,0.07%.It can be used for the determination of levamisole content and stability test.The RSD value results of sample recovery and precision were less than 2%,which met the methodological requirements.By controlling the single variable to carry on the single factor experiment,from the xanthan gum,sodium carboxymethyl cellulose,methyl cellulose,three suspended aid nine common dose extract three subsidence volume ratio,and dispersion is optimal dosage,again through the orthogonal experiment set three factors(xanthan gum,sodium carboxymethyl cellulose,micro powder silica gel)and a blank group,sedimentation volume,and dispersion as indicators selected the optimal prescription for A1B3C3,sedimentation volume F=0.98.Stability test was carried out on the selected prescription.In high temperature(60 ?)experiments and the results of the 10 d as appearance shape by a kind of white powder into a white cake,ivermectin content plus or minus 1.62% decline from 98.87±1.62% to 84.83±2.45%,content of levamisole decline from 99.95±1.24% to 90.21±1.06%;In the high humidity(90% RH)experiment,the results on 0 d and 10 d showed that the appearance changed from white powder to white agglomeration,the ivermectin content decreased from 98.87±1.62% to 82.45±1.32%,and the levoimidazole content decreased from 99.95±1.24% to 79.50±2.47%.In the strong light(4500 Lx)experiment,there was no significant change in appearance and shape on 0d and 10 d.The content of ivermectin decreased from 98.87±1.62% to 86.35±1.52%,and the content of levamisole decreased from 99.95 ±1.24% to 91.60± 1.47%.A high performance liquid chromatography-fluorescence detector(HPLC-FLD)and a high performance liquid chromatography-ultraviolet detector(HPLC-UV)were established for the determination of ivermectin and levamisole in compound ivermectin dry suspension in rat plasma.In the fluorescence detector,plasma samples were treated with liquid-liquid extraction method,and ethylenitrile and n-hexane were extracted and purified before content determination.Determined by external standard method to chromatographic column: Waters C18(5 ?m,4.6 mm *200 mm),the velocity: 1.5 m L/min,column temperature: 35 ?,excitation wavelength of 365 nm,the emission wavelength of 475 nm,mobile phase: methanol,acetonitrile and water gradient elution.In the UV detector,liquid-liquid extraction,carbonate buffer and ethyl acetate were also used for extraction.After purification,the liquid was dried with a nitrogen blower,and then the mobile phase was added for dissolution for content determination.The chromatographic column C18(150 mm × 4.6 mm,size 5 ?m),the velocity: 1 m L/min,detection wavelength: 220 nm,sample quantity: 20 ?L,column temperature: 30 ?,the mobile phase: sodium dihydrogen phosphate diethylamine + ethanol(volume elution of 70+30,content determination).Six SD rats were intragastrically administered,and the blood concentration of the rats was determined by high-performance liquid chromatography with 0.5 m L of blood collected at ten different time points after administration.A method of HPLC was established for the determination of plasma concentration in rats.The results showed that ivermectin and levamisole were consistent with the two-compartment model,and the pharmacokinetic parameters t1/2z were 112.308±9.030 hand 5.222±2.793 h;AUC(0-t)were 10075.167±511.002 ?g/L*h and 8925.917±949.401 ?g/L*h;AUC(0-?)were 10238.904±497.097 ?g/L*h and 9618.456±1128.521 ?g/L*h,Tmax were 12 h and4 h;Cmax were 56 ?g/L and 951 ?g/L.Above experiments show that the compound ivermectin dry suspension agent the best preparation technology for ivermectin(principal)2.0 g,levamisole,40 g(principal),xanthan gum(suspended aid)A1,sodium carboxymethyl cellulose(suspended aid)B3,powder,silica gel(within hygroscopic agent,flow aid and dispersant)C3,Sucrose powder(taste masking agent,filling agent)to 100 g,good stability,and according to the in vivo understand compound drug ivermectin dry suspension agent when the curve and the pharmacokinetic parameters,analysis of the available ivermectin and levamisole absorbed completely,relatively high bioavailability,long half-life,The slow excretion provides a strong theoretical basis for the research and production of the following preparations. |
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