Simultaneous determination of pioglitazone and candesartan in human plasma by LC-MS/MS and its application to a human pharmacokinetic study A simple and rapid liquid chromatography-tandem mass spectrometric(LC-MS/MS) assay method has been developed and fully validated for simultaneous quantification of pioglitazone and candesartan in human plasma.Irbesartan was used as an internal standard.The analytes were extracted from human plasma samples by solid-phase extraction technique using a Strata-X 33 mm polymeric sorbent.The reconstituted samples were chromatographed on a C18 column by using a 80:20(v/v) mixture of acetonitrile and 0.1% formic aci... Capture of cervical exfoliative cells on a glass slide coated by 3-glycidyloxypropyl trimethoxysilane and poly-L-lysine A new modification method for glass slides was developed and applied to make ThinPrep Pap smears,in order to increase the adhesion ability of cervical exfoliative cells.3-glycidyloxypropyl trimethoxysilane(GOPS) was coated on the glass slides firstly on the slides,then poly-L-lysine(PLL) was covalently modified onto the above epoxy-terminated slides to form GOPS-PLL double decorated slides.The modified slides were characterized using X-ray photoelectron spectroscopy(XPS) and atomic force microscopy(AFM).The... Quantification of desloratadine in human plasma by LC-ESI-MS/MS and application to a pharmacokinetic study A simple, sensitive, and specific liquid chromatography tandem mass spectrometry (LC-MS/ MS) method was developed for the quantification of desloratadine (DL) in human plasma using desloratadine-d5 (DLD5) as an internal standard (IS). Chromatographic separation was performed using an Xbridge C18 column (50 mm 4.6 mm, 5 mm) with an isocratic mobile phase composed of 10 mM ammonium formate: methanol (20:80, v/v), at a flow rate of 0.7 mL/min. DL and DLD5 were detected with proton adducts at m/z 311.2-259.2 an... Preparation of gastro-resistant pellets containing chitosan microspheres for improvement of oral didanosine bioavailability The purpose of this work was to introduce a new concept of coated pellets containing chitosan microspheres loaded with didadosine for oral administration,aiming at reducing the frequency of administration and improving the bioavailability by a suitable release profile.Chitosan microspheres were produced under fiuidized bed,followed by extrusion and spheronization to obtain pellets with a mean diameter of about 1 mm.The pellets were then coated with Kollidon VA64 and Kollicoat MAE100P in water dispersion t... Adsorptive stripping voltammetric methods for determination of aripiprazole Anodic behavior of aripiprazole(ARP) was studied using electrochemical methods.Charge transfer,diffusion and surface coverage coefcients of adsorbed molecules and the number of electrons transferred in electrode mechanisms were calculated for quasi-reversible and adsorp-tion-controlled electrochemical oxidation of ARP at 1.15 V versus Ag/AgCl at pH 4.0 in Britton-Robinson buffer(BR) on glassy carbon electrode.Voltammetric methods for direct determination of ARP in pharmaceutical dosage forms and biological ... Validated spectrofluorimetric method for the determination of atorvastatin in pharmaceutical preparations A rapid,sensitive and simple spectrofluorimetric method was developed for the estimation of atorvastatin.In this method,the native fluorescence characteristics of atorvastatin have been studied in both acidic and basic media.High sensitivity was obtained with 5% acetic acid at 389 nm using 276 nm for excitation.Regression analysis showed a good correlation coefficient(r=0.9995) between fluorescence intensity and concentration over the range of 1.5-4 mg/mL with detection limit of 0.012 mg/mL.The proposed met... High performance liquid chromatography mass spectrometric method for the simultaneous quantification of pravastatin and aspirin in human plasma:Pharmacokinetic application A rapid and sensitive liquid chromatography-tandem mass spectrometric(LC-MS/MS) assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma.Furosemide was used as an internal standard.Analytes and the internal standard were extracted from human plasma by liquid-liquid extraction technique using methyl tertiary butyl ether.The reconstituted samples were chromatographed on a Zorbax SB-C_18 column by using a mixture of 5 mM ammonium acetate... Simple and sensitive determination of sparfloxacin in pharmaceuticals and biological samples by immunoassay Plasma quinolone concentrations are not routinely measured in clinical practice.However,in order to optimize quinolone treatment,monitoring of plasma concentrations could sometimes be useful particularly in critically ill patients.In this study,anti-sparfloxacin antibody was obtained by immunizing rabbits with sparfloxacin conjugated with bovine serum albumin using isobutyl chloroformate method.After the assay procedure was optimized,the standard curve of sparfloxacin was established.The practical measuring... Analysis of species-dependent hydrolysis and protein binding of esmolol enantiomers The stereoselective hydrolysis of esmolol in whole blood and in its separated components from rat,rabbit and human was investigated.Blood esterase activities were variable in different species in the order of rat>rabbit>human.Rat plasma showed the high esterase activity and had no stereoselectivity to enantiomers.Rabbit red blood cell(RBC) membrane,RBC cytosol and plasma all hydrolyzed esmolol but with different esterase activity,whereas the hydrolysis in RBC membrane and cytosol showed significant stereose... Validated gradient stability indicating HPLC method for determining Diltiazem Hydrochloride and related substances in bulk drug and novel tablet formulation A stability-indicating liquid chromatographic method has been developed and validated for the determination of Diltiazem Hydrochloride(DTZ) together with its six related substances(Diltiazem sulphoxide,Imp-A,Imp-B,Imp-D,Imp-E,and Imp-F) in a laboratory mixture as well as in a novel tablet formulation developed in-house.Efficient chromatographic separation was achieved on a Hypersil BDS C_18(150 mm*4.6 mm,5.0 μm) with mobile phase containing 0.2% Triethylamine(TEA) in gradient combination with acetonitrile(A... Simultaneous determination of oleanolic acid and ursolic acid by RP-HPLC in the leaves of Eriobotrya japonica Lindl Oleanolic acid(OA) and ursolic acid(UA) are isomeric triterpenic acids and only one methyl‘s position is different between them.OA and UA always exist in the same plant,so it is difficult to separate them when determining contents by RP-HPLC.In this study,a very simple mobile phase for HPLC was developed to simultaneously determine UA and OA,and the factors affecting separation were also discussed.The mobile phase is methanol:water(95:5) with flow rate 0.4 mL/min.The retention time for OA and UA was 20.58 a... Application of analytical instruments in pharmaceutical analysis GCMS-QP2010 The GCMS-QP2010 Ultra is our most advanced gas chromatograph mass spectrometer.Descended from the GCMS-QP2010 Plus,it features best-in-class scan speed and sensitivity.