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OBJECTIVE： To establish a method for the concentration determination of levofloxacin in rat plasma and compare the pharmacokinetic difference between Levofloxacin tablets and gastric floating sustained-release pellets in rats. METHODS： SD rats were randomly divided into Levofloxacin tablets group and Levofloxacin gastric floating sustained-release pellets group， with 6 rats in each group. They were given relevant medicine intragastrically 40 mg/kg （taking normal saline as solvent）， and the blood samples 0.3 mL were collected before medication and 0.25， 0.5， 1， 2， 4， 8， 12， 24 h after medication. The plasma concentration of levofloxacin in rats was determined by UPLC. The determination was performed on Waters Acquity UPLC BEH C18 column with mobile phase consisted of 0.1％ formic acid-acetonitrile （78 ∶ 22，V/V） at the flow rate of 0.3 mL/min. The detection wavelength was set at 294 nm， and column temperature was 40 ℃. The sample size was 2 μL. The pharmacokinetic parameters of rats were calculated by using DAS 3.0 software， and the difference between them were detected by F-test. RESULTS： The linear range of levofloxacin was 0.20-20.12 μg/mL， and limit of quantitation was 0.20 μg/mL. The limit of detection was 0.04 μg/mL. The intra-day and inter-day RSDs were less than 10％. The recoveries were all in line with the related requirements of quantitation analysis of the biological samples stated in 2015 edition of Chinese Pharmacopeia. Average drug concentration-time curves of single dose of Levofloxacin tablets group and Levofloxacin gastric floating sustained-release pellets group were all in line with two-compartment model after intragastric administration. The pharmacokinetic parameters cmax were （12.13±1.67） and （8.76±1.13） μg/mL； tmax were（0.86±0.15） and （2.48±0.45）h； t1/2β were（4.67±0.95） and （6.67±1.01）h； AUC0-t were （42.95±4.21） and （126.48±9.44） μg·h/mL； AUC0-∞ were （50.66±6.72） and （132.61±10.63） μg·h/mL， respectively. Compared with Levofloxacin tablets， cmax of Levofloxacin gastric floating sustained-release pellets were decreased significantly， and tmax， t1/2β， AUC and mean retention time were prolonged or increased significantly （P＜0.05）， and relative bioavailability was 294％. CONCLUSIONS： Established UPLC method is simple， specific， sensitive and precise， and can be used for the determination of levofloxacin concentration in rat plasma and its pharmacokinetic study. After levofloxacin is made into gastric floating sustained-release pellets， pharmacokinetic parameters are changed significantly， retention time is prolonged significantly and bioavailability is improved significantly.
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OBJECTIVE:To study the absorption features of Silymarin enteric coated-polyllactic-co-glycolic acid (PLGA) nanoparticles in rat in situ intestine perfusion model and colonic adenoma Caco-2 cell model. METHODS:HPLC method was used to determine the content of silymarin. The absorption rate constant(Ka)and apparent absorption coefficient(Kapp)of Silymarin sus-pension,Silymarin PLGA nanoparticles and Silymarin enteric coated-PLGA nanoparticles were investigated in duodenum,jejunum, ileum and colon of rat in situ intestine perfusion model;the apparent permeability coefficient (Papp) of those drugs containing low-concentration,medium-concentration and high-concentration(20,40,60 μg/mL)of silymarin in Caco-2 cell model were also investigated. RESULTS:Compared with Silymarin suspension,Ka and Kapp of Silymarin PLGA nanoparticles and Silymarin enteric coated-PLGA nanoparticles were all increased in duodenum,jejunum,ileum and colon(P0.05). CONCLUSIONS:Silymarin enteric coated-PLGA nanoparticles can effectively increase the intestinal ab-sorption,cellular uptake and transmembrane transport rate of silymarin.
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The writing of vocational college thesis is the maln way to test whether the students are able to analyze and solve practical problems with the professional knowledge and skills they've learnt, as well as improve the capability of production and practice. This paper analyzes the present situation of the thesis written by higher vocational college students majoring in pharmaceutical sci-ences, and figures out the four kinds of evaluation standards about graduation thesis for students in various pharmaceutical fields with different problems. The four kinds of evaluation standards includes key point analysis on Standard Operation Procedure (SOP), planning strategy for pharmaceutical mar-keting, investigation of rational use of drugs in hospitals and subject research. The author puts forward the solving method for the problem, and formulate the evaluation requirements.
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Objective To propose a method for the determination of droxidopa concentration in human plasma by HPLC method for the study of the pharmacokinetics of droxidopa.Methods After a single oral dose of 200 mg droxidopa capsule was administered to 12 healthy Chinese male volunteers,we used perchloric acid to precipitate proteinum and then determined the droxidopa concentration in plasma by HPLC.The pharmacokinetic parameters of droxidopa were calculated by 3P87 software.Results The linear range was 0.025-2 ?g/ml.Pharmacokinetic parameters were: T1/2(108.50?30.78)min,AUC(185.74?26.41) ?g?ml-1?min-1,CL(1.08?0.08)ml/min,Tmax(99.90?10.05)min,Cmax(0.74?0.08)?g/ml.At 10 h after administration,droxidopa was eliminated from the blood almost completely.Conclusion The method we proposed is sensitive,reproducible,and easy to operate.Pharmacokinetics of droxidopa in vivo is fitted to two-compartment model.