Quantification of pilsicainide in serum by capillary electrophoresis

A new method for determining pilsicainide concentration in serum by rapid and selective capillary electrophoresis has been developed and validated. For pretreatment, serum was made alkaline and then extracted with diethyl ether. Procainamide was used as an internal standard. Sodium dihydrogenphosphate buffer (pH 2.29; 0.1 M) was used as a running buffer. A fused-silica capillary tube was loaded with a voltage of 25 kV and detection was performed at UV 200 nm. Good linearity (0-2.5 microg/ml) was obtained with the minimum limit of detection being 0.04 microg/ml serum (signal-to-noise ratio, 3:1). The R.S.D. of within-run reproducibility was 0.798-2.32%, that of between-run reproducibility was 4.74-5.12% and the recovery rate was 61-63%. Disopyramide, another anti-arrhythmic drug, was close to pilsicainide in terms of migration time. This method was applied to determination of pilsicainide in serum samples.     

A novel chemiluminescence method for determination of terbutaline sulfate based on potassium ferricyanide oxidation sensitized by rhodamine 6G

This work reports a novel flow injection-chemiluminescence (FI-CL) system for determination of terbutaline sulfate, a drug for treatment of asthma and chronic obstructive pulmonary disease (COPD). It is based on the reaction of potassium ferricyanide with terbutaline sulfate in sodium hydroxide medium sensitized by the fluorescent dye rhodamine 6G. With the peak height as a quantitative parameter applying optimum working conditions, terbutaline sulfate is determined over the range of 0.01-1.2 microg ml(-1) with a detection limit of 6.7 x 10(-3) microg ml(-1). The relative standard deviation (R.S.D.) is 3.7% for 0.1 microg ml(-1) terbutaline sulfate (n = 11). The proposed method is sensitive, simple, rapid, and was applied to determination of terbutaline sulfate in pharmaceutical preparations. The possible chemiluminescence (CL) reaction mechanism was also discussed briefly.     

Method development and validation for the simultaneous determination of cetirizine dihydrochloride, paracetamol, and phenylpropanolamine hydrochloride in tablets by capillary zone electrophoresis

A simple, selective, and cost effective capillary zone electrophoresis (CZE) method has been developed for the simultaneous separation and determination of cetirizine dihydrochloride (CTZ), paracetamol (PARA), and phenylpropanolamine hydrochloride (PPA) in tablets. A 10 mM sodium tetraborate background electrolyte (BGE) solution (pH 9.0) was found to be suitable for separation of all the analytes. An uncoated fused-silica capillary of a total length of 76 cm (effective length 64.5 cm) was used for separation. All the analytes were completely separated within 10 min at the applied voltage of 20 kV (current produced approximately 21 microA), and detection was performed at 195 nm with an UV detector. Ibuprofen was used as internal standard (I.S.) for the quantification of the drugs. Validation of the method was performed in terms of linearity, accuracy, precision, limit of detection (LOD), and quantification (LOQ). The linearity of the calibration curves for CTZ, PARA, and PPA (tested range) were 2-50 microg ml(-1) (r(2)=0.9982), 10-1000 microg ml(-1) (r(2)=0.9978), and 10-100 microg ml(-1) (r(2)=0.9986), respectively. The proposed method has been applied for the determination of active ingredients in tablets, and the recovery was found to be > or =98.60% with the relative standard deviation (R.S.D.) < or =1.56%. The LOQ of the CTZ, PARA, and PPA was found to be 2.0, 2.0, and 4.0 microg ml(-1), respectively. There were no interfering peaks due to the excipients present in the pharmaceutical tablets. Thus, the proposed method is simple and suitable for the simultaneous analysis of active ingredients in tablet dosage forms.     

Determination of the antimalaria drug artemether in pharmaceutical preparations by differential pulse polarography

A differential pulse polarographic method has been developed for the determination of artemether in its pharmaceutical formulations. The polarographic behaviour of artemether was examined in various buffer systems over the pH range 3.0-10.0. In phosphate buffer pH 5.5/methanol solution (7:3, v/v) the differential pulse polarograms displayed reproducible peaks at Ep-0.01 V versus Ag/AgCl. Under these conditions strict linearity between artemether concentration and peak height was observed in 3.4x10(-7)-3.0x10(-5)mol/L concentration range (R=0.9998). The detection limit was calculated to be 32 ng/mL. The polarographic method was applied to the determination of the content of artemether in tablets and capsules by using the standard addition method. The analysis of tablets containing 20mg artemether showed a mean value of 19.73 mg with a relative standard deviation (R.S.D.) of +/-1.01%. A content of 39.74 mg artemether was found in 40 mg capsules with a relative standard deviation of +/-0.53%. The polarographic method is characterised to be cheap, precise and not time-consuming and can therefore be used for routine analysis of artemether in its pharmaceutical preparations.     

HPLC method for the determination of ecdysterone in extractive solution from Pfaffia glomerata

A RP-LC method was developed and validated to quantify ecdysterone in extractive solution from subterraneous parts of Pfaffia glomerata. The analysis was performed using a RP-18 column with acetonitrile:water isocratic elution and the detection was carried out by UV at 242 nm. The standard curve for ecdysterone was linear over the range of 5.2-41.6 microg/ml (R2=0.9995). The extractive solution showed linear response in the range of 25.05-175.35 microg/ml (R2=0.9977). This method showed excellent repeatability (relative standard deviation, R.S.D.<2.0%), intermediary precision (R.S.D.=2.13%) and accuracy (101.04; R.S.D.=1.51%). The limit of detection (LOD) was 0.036 microg/ml and the limit of quantification (LOQ) was 0.110 microg/ml, demonstrating the sensitivity of the method. This assay can be readily utilized as quality controlled method for P. glomerata preparations.     

Capillary gas chromatographic determination of phenylpropanolamine in pharmaceutical preparation

Analytical procedure has been developed for the gas chromatographic determination of phenylpropanolamine (PPA) using trifluoroacetylacetone (FAA) as derivatizing reagent. Elution is carried out from the column HP-5 (30 mx0.32 mm i.d.) with film thickness 0.25 microm at initial column temperature 70 degrees C for 5 min, followed by heating rate 10 degrees C/min up to 120 degrees C. Injection port temperature was maintained at 270 degrees C. Nitrogen flow rate was 2 ml/min and detection was by FID. The linear calibration curve was obtained with 30-150 microg/ml PPA with detection limit of 6.0 microg/ml. The method was used for the determination of PPA from Sinutab and Tavegyl-D tablets. The relative standard deviation (R.S.D.) for the analysis of pharmaceutical preparation was obtained within 0.4-0.9%.     

Evaluation of the iCE280 Analyzer as a potential high-throughput tool for formulation development

The iCE280 Analyzer (iCE280) was evaluated for its potential application as a high-throughput tool to determine pI and separate charge related species using glycosylated, non-glycosylated and pegylated protein therapeutics as models. Resolution was achieved for glycosylated and non-glycosylated molecules, but remained a challenge for pegylated proteins. The sources of charge variants were determined to be the presence of C-terminal lysine residues, sialic acid content, and deamidation. Limited assay performance evaluation demonstrated that the method was linear in the concentration range of 2-333 microg/ml of IgG with linear regression coefficients of 0.984, 0.998, and 0.990 for acidic, main and basic species, respectively. Limit of detection and limit of quantitation were determined to be 3 and 11 microg/ml. The R.S.D. for intra- and inter-day precision as well as reproducibility was determined to be 0.2% or less for all pI values and 1.4% or less for acidic and main peak area distribution; the R.S.D. for basic peak area distribution was 5.7% or less. Robustness testing was performed by deliberately deviating +/-50% of pharmalyte concentration away from the desired condition. This deviation revealed a pI shift of only 0.06 units and resulted in no significant impact on area percent distribution. Utilization of iCE280 Analyzer eliminated the mobilization step associated with traditional capillary isoelectric focusing analysis and increased analytical throughput at least 2-fold.     

Pharmacokinetic study of trimebutine maleate in rabbit blood using in vivo microdialysis coupled to capillary electrophoresis

In vivo microdialysis was used together with capillary electrophoresis (CE) to monitor the concentration of trimebutine maleate (TM) in rabbit blood. Dialysis probe was perfused at 3 microl/min resulting in relative recovery of 26.6+/-3.1% (n=3). After a one step sample preparation the samples were injected directly into the capillary. TM was detected on-column using UV detector at 214 nm. Separation of TM from other components in the dialysate was achieved within 15 min. Evaluation was based on the relative collected peak height (TM/IS). The response for TM in the blood dialysate was linear over the range of 0.5-100 microg/ml. The detection limit of TM in the blood dialysate was 0.1 microg/ml (S/N=3). This method has been successfully applied to the pharmacokinetic study of trimebutine maleate in rabbit blood following oral administration of 200 mg/kg. It provides a fast and simple technique for the pharmacokinetic study of TM in vivo.     

Chiral separation and quantitation of pentazocine enantiomers in pharmaceuticals by capillary zone electrophoresis using maltodextrins

The chiral separation of pentazocine was achieved by capillary electrophoresis using oligosaccharides. Enantiomers were separated on 100 mM Tris/H3PO4 buffer (pH 2.5) with 5% maltodextrin as a chiral selector, and migration behavior was monitored at 200 nm. Under these conditions, (-)- and (+)-pentazocine and dextromethorphan (internal standard) migrated within 9 min, and the resolution of pentazocine enantiomers was 2.54. Linear calibration curves were obtained in the range 5-50 microg/ml(-1) for each enantiomer. The detection limit of pentazocine enantiomers was 29 pg, and the recoveries of(-)- and (+)-pentazocine were 98.9 (R.S.D., 3.4%) and 101.4% (R.S.D., 4.3%) with 10 microg/ml(-1), respectively.     

Chiral analysis of selected dopamine receptor antagonists in serum using capillary electrophoresis with cyclodextrin additives

Dopamine D-2 receptor antagonists' eticlopride and sulpiride were determined in serum using capillary electrophoresis with cyclodextrin additives. Chiral resolution of S(-) and R(+) sulpiride and eticlopride were achieved using 2% sulfated-beta-cyclodextrin (S-beta-CD) in 20 mM citrate run buffer (pH 2.90). A 72-cm fused silica capillary operated in the reversed polarity mode voltage of 20 kV was used for the analysis. The analytes of interest were isolated from serum using a solid phase extraction procedure with recoveries in excess of 85% for all four enantiomers. The D-2 receptor antagonist (-) butaclamol was used as internal standard. The limits of detection were 0.3 and 0.1 microg/ml for S(-) and R(+) eticlopride and for S(-) and R(+) sulpiride, respectively, in 1 ml of serum. The limits of quantitation were 2 and 1 microg/ml for S(-) and R(+) eticlopride, and for S(-) and R(+) sulpiride, respectively. Calibration curves were linear over the 2-20 micro/ml range for eticlopride and 1-20 microg/ml range for sulpiride. The coefficients of determination were greater than 0.99 (n = 12 for eticlopride and n = 15 for sulpiride). Precision and accuracy of the method were 0.27-6.38 and 0.20-3.60% for S(-) eticlopride, 2.33-4.28 and 0.80-5.73%, for R(+) eticlopride, 3.46-6.84 and 0.80-4.26%, for S(-) sulpiride; and 4.71 -6.47 and 2.00-6.67%, for R(+)-sulpiride, respectively.     

Method development and validation for the GC-FID assay of tributyl phosphate in a phospholipid emulsion

This paper describes the development and validation of an isothermal GC-FID method for the assay of tributyl phosphate in a phospholipid emulsion. The emulsion is used as a topical ointment to deliver Triton X-100, a spermicide. The tributyl phosphate is added to the emulsion as a plasticizer or softening agent. The chromatographic conditions of the method employ a J&W DB-Wax capillary column (30 m x 0.53 mm, film thickness 1 microm), isothermal elution with He at a column flow of 2.0 ml/min, injector, detector, and oven temperatures at 210 degrees C, a split ratio of 18.0/2.0, and a 3-microl injection volume. Sample calibration was performed with tributyl phosphate purchased from Aldrich (USP Reference Standard is not available). The linearity of the tributyl phosphate peak area responses was demonstrated from approximately 50 to 150% of the analytical concentration of 100 microg/ml. System precision was determined from five replicate injections of a standard and sample solution. Reproducibility of the tributyl phosphate peak area responses showed R.S.D. of 1.2 and 0.4%, respectively. Method precision was performed by assaying five samples by two different analysts on different days. The mean %LC was 95.5% (R.S.D.=1.0%) for the first analyst, and 95.6% (R.S.D.=1.0%) for the second analyst. The mean %LC value for all ten sample preparations was 95.5% (R.S.D.=0.9%). The limits of detection and quantitation were determined to be 0.2 and 0.7 microg/ml, respectively.     

Simultaneous determination of HIV-protease inhibitors lamivudine and zidovudine in pharmaceutical formulations by micellar electrokinetic chromatography

A micellar electrokinetic chromatographic (MEKC) method for the simultaneous separation and determination of lamivudine (LMV) and zidovudine (ZDV) in pharmaceutical formulation has been developed. Factors that affect the separation, such as buffer pH, surfactant concentration (sodium dodecyl sulfate, SDS), organic solvents and applied voltage were optimized. Buffer consisting of 12.5 mM sodium tetraborate decahydrate and 15 mM boric acid adjusted at pH 10.8, containing 90 mM SDS and 5% (v/v) acetonitrile (ACN) was found to be suitable for the separation of the drugs. p-Aminobenzoic acid (PABA) was used as internal standard (I.S.). Detection of analytes and I.S. was performed at a wavelength of 210 nm. It was observed that both the drugs and I.S. were migrated within 20 min at the applied voltage of +10 kV. Validation of the method was performed in terms of linearity, accuracy, precision, limit of detection (LOD) and quantification (LOQ). An excellent linearity was obtained in the concentration range 10-80 microg/ml for LMV and 10-100 microg/ml for ZDV. The detection limits for LMV and ZDV were found to be 2.5 and 2.0 microg/ml, respectively. The optimized method was applied to the simultaneous determination of LMV and ZDV in pharmaceutical formulation and human plasma (spiked) samples. Recovery of both the drugs in tablet dosage form and spiked drugs in plasma were > or =99.72% (relative standard deviation (R.S.D.)< or =1.84%) and > or =80.4% (R.S.D.< or =5.4%), respectively. In the electropherogram no interfering peaks were observed in the region of analytes and I.S. due to inactive ingredients in the tablets and matrices in plasma.     

Spectrophotometric determination of piroxicam and tenoxicam in pharmaceutical formulations using alizarin

New spectrophotometric procedures have been established for the quantitation of piroxicam and tenoxicam. The procedures are based on the reaction between the examined drug and alizarin (I), alizarin red S (II), alizarin yellow G (III) or quinalizarin (IV) producing ion-pair complexes which can be measured at the optimum wavelength. The optimization of the reaction conditions is investigated. Beer's law is obeyed in the concentration ranges 0.05-2.40 microg ml(-1), whereas optimum concentration as adopted from Ringbom plots was 0.12-2.25 microg ml(-1). The molar absorptivity, Sandell sensitivity, detection and quantification limits are also calculated. The correlation coefficient was >/=0.9990 (n=10) with a relative standard deviation (R.S.D.) of 相似文献   

Separation and simultaneous determination of rutin, puerarin, daidzein, esculin and esculetin in medicinal preparations by non-aqueous capillary

A simple method for the simultaneous determination of five bioactive components (rutin, puerarin, daidzein esculin and esculetin) in traditional medicinal preparations by non-aqueous capillary electrophoresis with UV detection has been developed for the first time. A running buffer composed of 15% acetonitrile, 2.5% acetic acid and 90 mM sodium cholate in methanol was found to be the most suitable for this separation. The limits of detection for five analytes were over the range of 0.050-1.216 microg ml(-1). The relative standard deviations (R.S.Ds.) of the migration times and the peak areas of the analytes were in the range of 1.3-2.9% and 2.2-2.7% (intraday), 1.7-1.9% and 2.8-3.6% (interday), respectively. In the tested concentration range, linear relationships (correlation coefficients: 0.9974 for rutin, 0.9976 for puerarin, 0.9981 for daidzein, 0.9972 for esculin and 0.9929 for esculetin) between peak areas and concentrations of the analytes were obtained. This method has been successfully applied to simultaneous determination of the five bioactive components with recoveries over the range of 89.4-107.4%.     

Method development and validation for the simultaneous determination of cinnarizine and co-formulated drugs in pharmaceutical preparations by capillary electrophoresis

Rapid and simple capillary electrophoresis (CE) methods were developed for the simultaneous determinations of cinnarizine and domperidone (CN/DOM) and cinnarizine and nicergoline (CN/NIC) in their co-formulated tablets. The optimized CE conditions were as follows: running buffer, methanol-acetate buffer (pH 3.0, 10 mM) (80:20 and 85:15 (v/v) for CN/DOM and CN/NIC, respectively); applied voltage, 20 kV; UV detection wavelengths, 215 and 227 nm for CN/DOM and CN/NIC, respectively; hydrodynamic injection was performed at a height of 25 mm for 30 s. Quinine hydrochloride and nicardipine hydrochloride were used as internal standards for the determination of CN/DOM and CN/NIC, respectively. Calibration curves were linear over the ranges 0.25-20/0.375-15 microg/ml (CN/DOM) and 0.25-25/0.4-10 microg/ml (CN/NIC) in each optimized condition. Detection limits were 0.074/0.119 microg/ml and 0.072/0.116 microg/ml for CN/DOM and CN/NIC, respectively. The proposed methods were successfully applied for the simultaneous determination of both CN/DOM and CN/NIC in their co-formulated tablets without interfering peaks due to the excipients present in the pharmaceutical tablets. The estimated amounts of CN/DOM and CN/NIC were almost identical with the certified values, and their percentage relative standard deviation values (%R.S.D.) were found to be < or =2.34% (n=3).     

On-line chemiluminescence determination protocatechuic aldehyde and protocatechuic acid in pharmaceutical preparations by capillary electrophoresis

Capillary electrophoresis (CE) with on-line direct chemiluminescence (CL) detection was first used in detecting protocatechuic aldehyde (PAH) and protocatechuic acid (PA) in their pharmaceutical preparations. It was found that the weak CL produced from the reaction of luminol with ferricyanide in an alkaline solution was strongly increased by PAH and PA which was separated by CE. Parameters affecting separation process and CL detection have been examined in detail. Under the optimum conditions, the baseline separation of PAH and PA was obtained within 6 min. The relative standard deviation (R.S.D.) for the analysis of PAH and PA was less than 1.1% for the migration time and 1.6% for the peak height. The detection limits (S/N=3) of PAH and PA were 7.0 x 10(-8)M and 5.0 x10(-8)M, respectively. The proposed method has been satisfactorily applied to the determination of PAH and PA in Salivia miltorrhrza pharmaceutical preparations.     

Simultaneous analysis of metabisulfite and sulfate by CE with indirect UV detection. Application to and validation for a pharmaceutical formulation

Metabisulfite is used as an antioxidant agent in a number of pharmaceutical formulations. In order to quantify simultaneously both metabisulfite and its oxidation product (sulfate), a capillary zone electrophoretic (CZE) method with indirect UV detection was developed. Best results were achieved with a background electrolyte (BGE) constituted of 15 mM pyromellitic acid, 15 mM tris-(hydroxymethyl)-aminomethane and 0.2 mM tetradecyltrimethylammonium bromide at pH 8.3 and an applied electrical field of 123 V/cm in a 32.5 cm fused silica capillary. Indirect UV detection was performed at a wavelength of 225 nm. In order to validate this method, an internal standard (IS), namely ammonium formate, was used. Moreover, due to the high chloride concentration in the pharmaceutical formulation, conductivity was adjusted by adding sodium chloride into standard solutions to prevent matrix effect. Linearity and accuracy were successfully tested in a concentration range of 33.3–250 μg/ml for sodium metabisulfite and of 50–375 μg/ml for sodium sulfate. Method precision was determined on six samples each day. Thereby, relative standard deviations (R.S.D.) of 6% and 12–13% were obtained for intra-day and inter-day precision, respectively. Considering the instability of metabisulfite and its use as an antioxidant agent and not as an active principle, the method was accepted and used for routine analyses.     

Determination of trimetazidine HCl by adsorptive stripping square-wave voltammetry at a glassy carbon electrode.

The adsorptive and electrochemical behavior of trimetazidine hydrochloride on a glassy carbon electrode were investigated in acetate buffer solution by using cyclic and square-wave voltammetry. Cyclic voltammetric studies indicated the oxidation of trimetazidine hydrochloride at the electrode surface through a single two-electron irreversible step and fundamentally controlled by adsorption. The solution condition and instrumental parameters were optimized for the determination of the authentic drug using adsorptive square wave stripping voltammetry. Trimetazidine hydrochloride gave a sensitive adsorptive oxidative peak at 0.750 V (vs. Ag/AgCl). The oxidation peak was used to determine authentic trimetazidine hydrochloride concentration in the range 5.0 x 10(-8)-5.0 x 10(-6) M with a detection limit of 2.0 x 10(-8) M. The procedure was successfully applied for assay of trimetazidine hydrochloride in the tablet dosage form (Vastarel). A mean recovery of 94.7% with a relative standard deviation (R.S.D.) of 0.88% was obtained. Applicability to assay the drug in urine samples was illustrated. The peak current was linear with the drug concentration in the range 17-85 microg per ml urine. The detection limit was 1.7 microg ml(-1) urine.     

Determination of celecoxib,a COX-2 inhibitor,in pharmaceutical dosage forms by MEKC

A micellar electrokinetic chromatographic (MEKC) method was developed for the quantification of celecoxib, a COX-2 inhibitor in pharmaceutical dosage forms within the total analysis time of 7 min. The method has been validated and proven to be rugged. The quantification was carried out at 35 degrees C and 25 kV, using a 25 mM borate buffer (pH 9.3), 25 mM sodium dodecyl sulphate with an extended light path capillary (48.5 cm x 50 micro I.D., 40 cm to detector). Calibration curves were constructed for celecoxib (0.2-0.6 mg/ml) by the internal standard method with 2-nitro aniline as an internal standard (coefficient of correlation greater than 0.999). The intermediate precision (between day precision) of migration times and peak area ratios of celecoxib to internal standard were 1.44 and 1.58% R.S.D., demonstrates good reproducibility of the method. The method was applied to a commercial celecoxib formulation (Revibra, 100 mg) and the percentage recoveries were ranged from 93.0 to 98.4%.     

A capillary zone electrophoresis method for the assay and quality control of mesembrine in Sceletium tablets

The Sceletium plant has been reported to contain psychoactive alkaloids, specifically mesembrine, mesembrenone, mesembrenol and other related alkaloids. Sceletium is marketed through health shops and on the internet as dried plant powder and as pharmaceutical dosage forms. The objectives of this research was to develop and validate a capillary zone electrophoresis (CZE) method to identify five alkaloids and quantitatively determine the content of the important alkaloid, mesembrine in Sceletium tablets. Since reference standards of the relevant alkaloids are not commercially available for use in quality control of Sceletium products, it was necessary to isolate and characterize an appropriate analytical marker for use in the assay and additional markers for fingerprinting by CZE. The separation of the relevant alkaloids was carried out by CZE on a 50cm effective length, fused silica capillary tubing (50microm i.d.x360microm o.d.) using 50mM of sodium dihydrogen orthophosphate dihydrate at pH 1.5 as the background electrolyte and monitored at a UV wavelength of 228nm. All the marker alkaloids were found to be well resolved and were identified in the plant material and in commercially available Sceletium tablets based on the relative migration times (MTs) with respect to quinine hydrochloride that was used as an internal standard. The method was validated and used to assay the mesembrine content in Sceletium tablets. Calibration curves were found to be linear over the entire concentration range of 2.5-80microg/ml with correlation coefficients >0.995. The accuracy was found to be 92.5 and 104.5% (R.S.D.<3.5%) and the R.S.D.'s of the inter-day precision at low, medium and high tablet masses were better than 0.9, 2.2 and 2.7%, respectively. The recoveries were all within the range of 91.8 and 105.8% (R.S.D.<8.5%) and the limit of quantitation (LOQ) and limit of detection (LOD) values were found to be 2.5 and 1.5microg/ml, respectively.