Method development and validation for the simultaneous determination of imatinib mesylate and N-desmethyl imatinib using rapid resolution high performance liquid chromatography coupled with UV-detection

We developed a simple and sensitive method for the simultaneous detection of imatinib mesylate (IM) and its active metabolite, N-desmethyl imatinib (M1), in human serum samples. Separation was successfully achieved using an Agilent(?) ZORBAX Eclipse plus C(18) reversed phase column (50 mm × 2.1 mm, i.d.; 1.8 μm) under isocratic mobile phase conditions consisting of acetonitrile: 0.02 M potassium dihydrogen phosphate with 0.2% triethylamine at pH 3 (25:75, v/v) and ultra-violet detection was achieved at 235 nm. Extraction of the target compounds was completed using 100% cold acetonitrile. Good linearities (r(2)>0.99) for both IM and M1 were achieved for the concentration ranges of 50-1800 ng/mL and 50-360 ng/mL, respectively. The detection limits were 20 ng/mL and 10 ng/mL for M1 and IM, respectively. The intra- and inter-day precisions were less than 1% with percent recoveries of more than 90%. The method was successfully applied to calculate the pharmacokinetic parameters of chronic myeloid leukemia patients receiving imatinib. The method is suitable to be routinely applied for determination of IM and M1 in serum.     

Simultaneous estimation of levodopa and carbidopa by RP‐HPLC using a fluorescence detector: its application to a pharmaceutical dosage form

A reverse‐phase high‐performance liquid chromatographic (RP‐HPLC) method was developed and validated for the simultaneous estimation of levodopa and carbidopa in bulk and pharmaceutical formulations. Chromatographic separation was achieved by using a C₁₈ reverse‐phase column and a mixture of an aqueous phase (10 mM potassium dihydrogen phosphate buffer, pH 4.0) and methanol (90:10 v/v) as the mobile phase. Quantitative analysis of levodopa and carbidopa was performed using a fluorescence detector at an excitation wavelength of 280 nm and an emission wavelength of 310 nm. The method was linear between 5 and 500 ng/mL for both levodopa and carbidopa. The detection limits for levodopa and carbidopa were 0.30 and 0.60 ng/mL, respectively, whereas the quantitation limit was 0.80 ng/mL for levodopa and 1.2 ng/mL for carbidopa. The method demonstrated good and consistent recoveries (99.63–100.80% for levodopa and 98.97–100.94% for carbidopa) with low interday and intraday relative standard deviation. The validated method was successfully applied to quantify levodopa and carbidopa simultaneously in a pharmaceutical formulation. The method was found to be precise, sensitive and accurate for the simultaneous determination levodopa and carbidopa in bulk and pharmaceutical formulations. Copyright © 2014 John Wiley & Sons, Ltd.     

Validation of high-performance liquid chromatography assay for quantification of formoterol in urine samples after inhalation using UV detection technique

A novel high-performance liquid chromatography (HPLC) assay for the estimation of formoterol in urine samples was developed and validated. A solid phase extraction (SPE) using Oasis HLB was optimised to isolate formoterol from a urine matrix followed by HPLC with UV detection. This extraction procedure concentrated the final analyte forty times so that UV detection can be used to determine even a low concentration of formoterol in urine samples. The urinary assay was performed in accordance with FDA and ICH regulations for the validation of bioanalytical samples. The samples were injected onto a C18 Spherisorb (250 mm x 4.6 mm x 5 microm) analytical column maintained at 30 degrees C. The mobile phase consisted of 5 mM of potassium dihydrogen orthophosphate buffer (adjusted to pH 3 with ortho phosphoric acid):acetonitrile (ACN) (70:30, v/v), and the formoterol peak was detected at wavelength 214 nm. The extraction recovery of formoterol from the urine sample was >95%. The calibration curve was linear (r2=0.99) over formoterol concentrations ranging from 1.5 to 25 ng/mL (n=6). The method had an accuracy of >92% and intra and inter-day precision CV% of <3.9% and <2.2%, respectively, at three different concentrations low, medium and high (10, 15, 20 ng/mL). The limit of quantification (LOQ) for formoterol was found to be 1.50 ng/mL. The accuracy and precision at the LOQ level were 95% and %CV <3.7% (n=10), respectively. The method reported is simple, reliable, precise, and accurate and has the capacity to be used for determination of formoterol in urine samples.     

顺式藁苯内酯口服给药在大鼠血浆和脑内的药动学特性(英文)

建立大鼠血浆和脑中Z-槀苯内酯(LIG)浓度测定的高效液相色谱法。采用Agilent Hypersil ODS C18色谱柱(150mm×4.6mm,5μm),流动相为甲醇-5%异丙醇水溶液(60:40,v/v),流速为1.0mL/min,检测波长为280nm。血浆与脑中槀苯内酯浓度线性检测范围分别为93.75~3750ng/m(r=0.9999)和93.75~3750ng/g(r=0.9997),日内及日间精密度RSD10%。本法适用于大鼠口服LIG后血浆及脑中药物浓度的研究。     

Simple and simultaneous determination for 12 phenothiazines in human serum by reversed-phase high-performance liquid chromatography

A high-performance liquid chromatographic method has been developed for the simultaneous analysis of the 12 phenothiazines (chlorpromazine, fluphenazine, levomepromazine, perazine, perphenazine, prochlorperazine, profenamine, promethazine, propericiazine, thioproperazine, thioridazine and trifluoperazine) in human serum using HPLC/UV. The separation was achieved using a C(18) reversed-phase column (250 mm x 4.6 mm I.D., particle size 5 microm, Inersil ODS-SP). The mobile phase, consisting of acetonitrile-methanol-30 mM NaH(2)PO(4) (pH 5.6) (300:200:500, v/v/v), was delivered at a flow rate of 0.9 mL/min and UV detection was carried out at 250 nm. The recoveries of the 12 phenothiazines spiked into serum samples were 87.6-99.8%. Regression equations for the 12 phenothiazines showed excellent linearity, with detection limits of 3.2-5.5 ng/mL for serum. The inter-day and intra-day coefficients of variation for serum samples were commonly below 8.8%. The selectivity, accuracy and precision of this method are satisfactory for clinical and forensic purposes. This sensitive and selective method offers the opportunity for simultaneous screening and quantification of almost all phenothiazines available in Japan for the purposes of clinical and forensic applications.     

Determination of echinacoside in rat serum by reversed-phase high-performance liquid chromatography with ultraviolet detection and its application to pharmacokinetics and bioavailability

A rapid and simple high-performance liquid chromatographic (HPLC) method has been developed and validated for the determination of echinacoside (ECH) in rat serum. After protein precipitation of serum sample with trichloroacetic acid, the supernatant was directly injected and analyzed on a C(18) CapcellACR analytical column (150 mm x 4.6mm I.D. 5 microm) with a mobile phase consisting of acetonitrile-0.5% acetic acid (15.5:84.5, v/v). The UV detector was set at 330 nm. The lower limit of detection and quantification were 9 and 29.2 ng/mL, respectively, and the calibration curves were linear over the concentration range of 29.2-18250 ng/mL. The assay method was successfully applied to the study of the pharmacokinetics and bioavailability of ECH in rat.     

Sensitive determination of trimetazidine in spiked human plasma by HPLC with fluorescence detection after pre-column derivatization with 9-fluorenylmethyl chloroformate

A high-performance liquid chromatographic method for the determination of trimetazidine dihydrochloride (TMZ) in spiked human plasma is described. The method is based on the pre-column derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) using the fluorimetric detection technique. Fluoxetine HCl (FLX) was used as internal standard. Both, TMZ and FLX were completely derivatized after heating at 50 degrees C for 20 min in borate buffer pH 8.0. Samples were analyzed by high performance liquid chromatography (HPLC) using Zorbax-TMS column (250 mm x 4.6 mm, i.d., 5 microm) and mobile phase consist of acetonitrile, methanol and 20 mM sodium acetate pH 4.7 (44:6:50; v/v/v). Fluorescence detector (FLD) was adjusted at excitation and emission wavelengths; 265 and 311 nm, respectively. The linearity of the method was in the range of 4.5-200 ng/ml. Limits of detection (LOD) and quantification (LOQ) were 1.5 and 4.5 ng/ml, respectively. Trimetazidine recovery was 96.5+/-1.3% (n=6; RSD=2.1%).     

Determination of atomoxetine in human plasma by a high performance liquid chromatographic method with ultraviolet detection using liquid-liquid extraction

A HPLC method with UV detection (210 nm) was developed and validated for the quantification of atomoxetine, a new medication for the treatment of attention deficit/hyperactivity disorder, in human plasma. Following a two-step liquid-liquid extraction with diethyl ether, the analyte and internal standard (maprotiline) were separated using an isocratic mobile phase of acetonitrile/phosphate buffer (39/61, v/v, pH 6.6) on a reverse phase Inertsil C(18) column. Linearity was verified over the range of 3.12-200 ng/mL atomoxetine in plasma. The lowest limit of detection is 2.5 ng/mL (S/N=10). This HPLC method was validated with within- and between-batch precisions of 4.9-14.4% and 4.7-13.1%, respectively. The within- and between-batch biases were -1.9 to 1.4% and 0.1-13.8%, respectively. Commonly used psychotropic drugs and frequently coadministered drugs did not interfere with the drug and internal standard. This method is simple, economical and specific, and has been used successfully in a pharmacokinetic study of atomoxetine.     

High-performance liquid chromatography method for the quantification of pantoprazole in human plasma

A sensitive and selective HPLC method with UV detection (290 nm) was developed and validated for quantitation of pantoprazole, proton-pump inhibitor, in human plasma. Following a single-step liquid-liquid extraction with methyl tert-butyl ether/diethyl ether (70/30, v/v), the analyte and internal standard (zonisamide) were separated using an isocratic mobile phase of 10mM phosphate buffer (pH 6.0)/acetonitrile (61/39, v/v) on reverse phase Waters symmetry C18 column. The lower limit of quantitation was 20 ng/mL, with a relative standard deviation of less than 4%. A linear range of 20-5000 ng/mL was established. This HPLC method was validated with between-batch and within-batch precision of 1.3-3.2% and 0.7-3.3%, respectively. The between-batch and within-batch bias was -0.5 to 8.2 % and -2.5 to 12.1%, respectively. This validated method is sensitive and repeatable enough to be used in pharmacokinetic studies.     

High-performance liquid chromatographic determination of quercetin in human plasma and urine utilizing solid-phase extraction and ultraviolet detection

An HPLC method for determining quercetin in human plasma and urine is presented for application to the pharmacokinetic study of rutin. Isocratic reversed-phase HPLC was employed for the quantitative analysis by using kaempferol as an internal standard. Solid-phase extraction was performed on an Oasis HLB cartridge (>95% recovery). The HPLC assay was carried out using a Luna ODS-2 column (150 x 2.1 mm I.D., 5 microm particle size). The mobile phase was acetonitrile-10 mM ammonium acetate solution containing 0.3 mM EDTA-glacial acetic acid, 29:70:1 (v/v, pH 3.9) and 26:73:1 (v/v, pH 3.9) for the determination of plasma and urinary quercetin, respectively. The flow-rate was 0.3 ml/min and the detection wavelength was set at 370 nm. Calibration of the overall analytical procedure gave a linear signal (r>0.999) over a concentration range of 4-700 ng/ml of quercetin in plasma and 20-1000 ng/ml of quercetin in urine. The lower limit of quantification was approximately 7 ng/ml of quercetin in plasma and approximately 35 ng/ml in urine. The detection limit (defined at a signal-to-noise ratio of about 3) was approximately 0.35 ng/ml in plasma and urine. A preliminary experiment to investigate the plasma concentration and urinary excretion of quercetin after oral administration of 200 mg of rutin to a healthy volunteer demonstrated that the present method was suitable for determining quercetin in human plasma and urine.     

Development and validation of a liquid chromatographic method for in vitro mupirocin quantification in both skin layers and percutaneous penetration studies

A simple, rapid, and sensitive reversed-phase high-performance liquid chromatographic (HPLC) method for the measurement of mupirocin concentrations in both skin layers and percutaneous samples has been developed. Mupirocin was extracted from skin layers using PBS-acetonitrile (90:10, v/v). The method is sufficiently sensitive and repeatable to be used in percutaneous penetration studies. The samples were chromatographed on a 250 mm x 4 mm C(8) LiChrospher Select B (5 microm). The mobile phase composition was a mixture of acetonitrile-ammonium acetate 0.05 M (27.5:72.5, v/v) adjusted to pH 6.3 with acetic acid. The analyte was detected at 228 nm and the run time was 11 min. Linearity was confirmed in the concentration range 0.2-20 microg/ml and the limit of detection was 9.5 ng/ml.     

HPLC-UV method development for fentanyl determination in rat plasma and its application to elucidate pharmacokinetic behavior after i.p. administration to rats

A simple, rapid and validated high performance liquid chromatography method with UV detection for the quantification of an opioid agonist, fentanyl (FEN), in rat plasma was developed. The assay procedure involved chromatographic separation using a ZIC-HILIC SeQUANT column (250 mm × 4.6 mm, i.d., 5 μm) and a mobile phase of acetonitrile and acetate buffer (pH 3.4, 20mM) of ratio (=65:35, v/v) at a flow rate of 1.2 mL/min and detection wavelength of 201 nm. Plasma sample (100 μL) pretreatment was based on simple deprotienization by acetonitrile spiked with clonidine as an internal standard (I.S.) of 20 ng/mL followed by extraction with tert-butyl methyl ether and centrifugation. The organic layer was evaporated under N(2) gas and reconstituted with 100 μL of acetate buffer (pH 3.4, 20mM), and 50-μL portions of reconstituted sample were injected onto the column. Sample analysis including sample pretreatment was achieved within 35 min. Calibration curve was linear (r ≥ 0.998) from 5 to 100 ng/mL. Both intra- and inter-day assay precisions that are presented through RSD were lower than 12.6% for intra-day and lower than 12.0% for inter-day assessment. Limit of detection was 0.8 ng/mL at S/N of 3. This method was omitting the use of expensive solid phase extraction and time consuming liquid extraction procedures. Moreover, the present method was successfully applied to study pharmacokinetic parameters of FEN after intraperitoneal administration to male Wistar rat. Pharmacokinetic parameters estimated by using moment analysis were T(1/2) 198.3 ± 44.7 min, T(max) 28.3 ± 2.9 min and AUC(0-180) 15.6 ± 2.9(× 10(2))ngmin/mL.     

Determination and validation of a simple high-performance liquid chromatographic method for simultaneous assay of iprodione and vinclozolin in human urine

A method based on solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) was developed for the simultaneous determination of 3-(3,5-diclorophenyl)-5-ethenyl-5-methyl-2,4-oxazolidinedione (vinclozolin) and 3-(3,5-diclorophenyl)-N-(1-methylethyl)-2,4-dioxo-1-imidazolidinecarboxamide (iprodione) in human urine. Urine samples containing vinclozolin and iprodione were collected by solid phase extraction using C(18) cartridges. The chromatographic separation was achieved on a Spherisorb ODS2 (250 mm x 4.6 mm, 5 microm) column with an isocratic mobile phase of acetonitrile-water (60:40, v/v). Detection was UV absorbance at 220 nm. The calibration graphs were linear from 30 to 1000 ng/mL for the two fungicides. Intra- and inter-day R.S.D. did not exceed 2.9%. The quantitation limit was 50 ng/mL for vinclozolin and 30 ng/mL for iprodione, respectively.     

Quantification of the HIV-integrase inhibitor raltegravir (MK-0518) in human plasma by high-performance liquid chromatography with fluorescence detection

A simple and sensitive HLPC method with fluorescence detection was developed for the accurate determination of the first licensed HIV integrase inhibitor raltegravir in human plasma. A 500-microL plasma sample was spiked with delavirdine as internal standard and subjected to liquid-liquid extraction based on a previously described assay i.e. using hexane/methylene chloride (1:1, v/v%) at pH 4.0. HPLC was performed using a Symmetry Shield RP18 column (150 mm x 4.6 mm), a gradient elution of acetonitrile -0.01% (v/v) triethylamine in water adjusted to pH 3.0 at a flow rate of 1 mL/min and a fluorimetric detector set at 299 and 396 nm as excitation and emission wavelengths, respectively. The retention time was 5.0 min for internal standard and 6.4 min for raltegravir. Calibration curves were linear in the range 5-1000 ng/mL and the accuracy of quality control samples in the range 10-750 ng/mL varied from 98.3 to 99.1% and 98.3 to 101.0% of the nominal concentrations for intra-day and day-to-day analysis, respectively with a precision of 6.3% or less. Among the other antiretroviral drugs which can be given in association to HIV-infected patients, none was found to interfere with internal standard or raltegravir. The described assay was developed for the purpose of therapeutic drug of this HIV integrase inhibitor.     

Liquid chromatographic method for the determination of rizatriptan in human plasma

A high-performance liquid chromatographic (HPLC) method with fluorescence detection has been developed for the determination of rizatriptan in human plasma. Following a single-step liquid-liquid extraction with methyl tertiarybutyl ether, the analytes were separated using a mobile phase consisting of 0.05% (v/v) triethylamine in water (adjusting to pH 2.75 with 85% phosphoric acid) and acetonitrile (92:8, v/v). Fluorescence detection was performed at an excitation wavelength of 225nm and an emission wavelength of 360nm. The linearity for rizatriptan was within the concentration range of 0.5-50ng/ml. The intra- and inter-day precisions of the method were not more than 8.0%. The lower limit of quantification (LLOQ) was 0.5ng/ml for rizatriptan. The method was sensitive, simple and repeatable enough to be used in pharmacokinetic studies.     

High-performance liquid chromatography method for the quantification of entacapone in human plasma

A simple, sensitive and selective HPLC method with UV detection (315 nm) was developed and validated for quantitation of entacapone in human plasma, the newest addition to the group of antiparkinsonian agents. Following a single-step liquid-liquid extraction (LLE) with ethyl acetate/n-hexane (30/70, v/v), the analyte and internal standard (rofecoxib) were separated using an isocratic mobile phase of 30 mM phosphate buffer (pH 2.75)/acetonitrile (62/38, v/v) on a reverse phase C18 column. The lower limit of quantitation was 25 ng/mL, with a relative standard deviation of less than 8%. A linear range of 25-2500 ng/mL was established. This HPLC method was validated with between-batch and within-batch precision of 2.2-4.2% and 1.7-7.8%, respectively. The between-batch and within-batch accuracy was 98.7-107.5% and 97.5-106.0%, respectively. Frequently coadministered drugs did not interfere with the described methodology. Stability of entacapone in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days storage in a freezer. This validated method is sensitive, simple and repeatable enough to be used in pharmacokinetic studies.     

Simultaneous determination of metolazone and losartan potassium in their binary mixtures using high‐performance liquid chromatography with fluorimetric detection: application to combined tablets and spiked human plasma

A new, specific and sensitive reversed‐phase high‐performance liquid chromatography method was developed for the simultaneous determination of metolazone (MET) and losartan potassium (LOS). Good chromatographic separation was achieved within 6.0 min on a 150 × 4.6 mm i.d., 5 µm Waters, Ireland and ProDIGY 5 ODS 3 100 A column. A mobile phase containing a mixture of methanol and 0.02 M phosphate buffer (65:35, v/v) at pH 3.0 was used. The analysis was performed at a flow rate of 1 mL/min with fluorescence detection at 410 nm after excitation at 230 nm. Aspirin (ASP) was used as an internal standard. The proposed method was rectilinear over 2.0–40.0 (MET) and 40.0–800.0 ng/mL (LOS), with limits of detection of 0.22 and 4.52 ng/mL and limits of quantification of 0.68 and 13.70 ng/mL for MET and LOS, respectively. The method was successfully applied for the simultaneous analysis of the studied drugs in their laboratory‐prepared mixtures, single tablets and co‐formulated tablets. Moreover, the method was applied to an in vitro drug release (dissolution) test. The method was further extended to the determination of LOS in spiked human plasma. Statistical evaluation and comparison of data obtained using the proposed and comparison methods revealed no significant difference between the two methods in addition to good accuracy and precision for the proposed method. Copyright © 2013 John Wiley & Sons, Ltd.     

HPLC method for determination of verapamil in human plasma after solid-phase extraction

A simple, rapid and precise HPLC method has been developed for the assay of verapamil in human plasma. The clean up of the plasma samples was tested using several adsorbents for solid-phase extraction and best recovery was obtained using mixed-mode cartridges (HLB - hydrophilic-lipophilic balance) ranging between 94.70 and 103.71%. HPLC separation was performed with isocratic elution on Lichrospher 60 RP-select B column (250 mm × 4 mm I.D., 5 μm particle size). The mobile phase was 40% acetonitrile and 0.025 mol/L KH₂PO₄ with pH 2.5 at flow rate of 1 mL/min. Diltiazem was used as internal standard and the detection wavelength was 200 nm. The calibration curves were linear in the range of 10–500 ng/mL. The developed method is convenient for routine analysis of verapamil in human plasma.     

Application of liquid chromatographic method with fluorescence detection for the determination of triclabendazole in tablets and biological fluids

A simple and rapid liquid chromatographic method was developed and validated for the determination of triclabendazole with high accuracy and precision within 6 min. Good chromatographic separation was achieved using a CLC Shim‐pack C₈ (250 × 4.6 mm, 5 µm particle size) using the mobile phase containing a mixture of 0.02 m phosphate buffer and methanol with a ratio of (20 : 80 v/v) at pH 4.0 was pumped at a flow rate of 1.2 mL/min with fluorescence detection for the first time at 338 nm after excitation at 298 nm. Losartan potassium was used as an internal standard. The method showed good linearity in the ranges of 0.05–2.0 µg/mL with limits of detection and quantification of 14.1 and 42.6 ng/mL, respectively. The suggested method was successfully applied for the analysis of triclabendazole in tablets. The high sensitivity of the method enabled the determination of the studied drug in spiked human plasma with mean percentage of recoveries of 99.79 ± 5.09. Statistical evaluation of the data was performed according to ICH Guidelines. Copyright © 2013 John Wiley & Sons, Ltd.     

Determination of aesculin in rat plasma by high performance liquid chromatography method and its application to pharmacokinetics studies

A sensitive and reproducible high performance liquid chromatography method with UV detection was described for the determination of aesculin in rat plasma. After deproteinization by methanol using metronidazole as internal standard (I.S.), solutes were evaporated to dryness at 40 degrees C under a gentle stream of nitrogen. The residue was reconstituted in 100 microl of mobile phase and a volume of 20 microl was injected into the HPLC for analysis. Solutes were separated on a Diamonsil C18 column (250 mm x 4.6 mm i.d., 5 microm particle size, Dikma) protected by a ODS guard column (10 mm x 4.0 mm i.d., 5 microm particle size), using acetonitrile-0.1% triethylamine solution (adjusted to pH 3.0 using phosphoric acid) (10:90, v/v) as mobile phase (flow-rate 1.0 ml/min), and wavelength of the UV detector was set at 338 nm. No interference from any endogenous substances was observed during the elution of aesculin and internal standard (I.S., metronidazole). The retention times for I.S and aesculin were 10.4 and 12.4 min, respectively. The limit of quantification was evaluated to be 57.4 ng/ml and the limit of detection was 24.0 ng/ml. The method was used in the study of pharmacokinetics of aesculin after intraperitoneal injection (i.p.) administration in rats.