Capillary Zone Electrophoretic Method Research Articles

Development of Capillary Zone Electrophoresis Method for the Simultaneous Separation and Quantification of Metformin and Pioglitazone in Dosage Forms; and Comparison with HPLC Method.

A capillary zone electrophoretic (CZE) method was developed, validated, and applied for the assay of metformin (MET) and pioglitazone (PIO) in pharmaceutical formulations. The optimum running buffer composition was found to be 75 mmol/L phosphate buffer containing 30% acetonitrile (ACN) at pH 4.0. The optimum instrumental conditions were found to be injection time, 10 s; applied voltage, 25 kV; hydrodynamic injection pressure, 0.5 psi for 10 s, capillary temperature, 25 °C; and the detection wavelength, 210 nm. The quantifications were calculated based on the ratio of the peak areas of analytes to atenolol as an internal standard. The CZE method was validated in terms of accuracy (98.21-104.81%), intra- and inter-day precision of migration time and peak area (relative standard deviation ≤ 5%), linearity (correlation coefficients ≥ 0.9985), limit of detection (≤0.277 μg/mL), and limit of quantitation (≤0.315 μg/mL). The proposed method was applied for the analysis of PIO and MET both individually and in a combined dosage tablet formulation. All electrophoretic parameters were calculated and evaluated. A previously reported high-performance liquid chromatographic (HPLC) method was also applied to the same samples. A comprehensive comparison was then carried out for the analytical features of both methods CZE and HPLC. Comparable results were obtained with the advantage of reagent consumption and separation efficiency of CZE over HPLC and shorter analysis time by HPLC compared with CZE.

In situ green analytical methods for the rapid and sensitive determination of a newly launched orphan anticancer drug; Tigecycline in infusion bags: comparative study

BackgroundTigecycline (TIG), an antimicrobial agent indicated for complex bacterial infections, is now approved by FDA as an orphan chemotherapeutic agent for the treatment of acute myeloid leukemia due to its inhibitory effects on pathways of activating, signaling and abnormal mitochondrial function in cancer cells. TIG is mainly administered as intravenous infusion through centralized unit of oncology centers. This necessitates the continuous analytical quality control of the prepared solution in order to identify and quantify TIG for safe intravenous administration to patients. Moreover, the clinical staff exposure risk to toxic drugs during daily handling must be considered. Such concerns require a fast, cost-effective and green analytical procedure for sensitive determination of TIG directly in infusion bags. In this work, we propose a simple, rapid and green capillary zone electrophoretic (CZE) method for the sensitive assay of TIG directly in infusion bags, in addition to three simple and green spectrophotometric methods.ResultsTIG solutions corresponding to clinical ranges were detected in 5%glucose. Validation of all the proposed methods was according to ICH guidelines. Greenness assessment was performed depending on Green Analytical Procedure Index (GAPI) and the Eco-scale approach which showed that the proposed methods are better eco-friendly methods than reported ones. It also revealed the superiority of our proposed methods in terms of simplicity and sensitivity for TIG determination in infusion bags. Quantification limits obtained were significantly lower than the administered range of TIG in infusion bags and lower than its maximum serum concentration (Cmax). This promotes the application of the proposed methods for the pharmacokinetics and bioavailability studies of TIG in various biological fluids.ConclusionsThis work reports, for the first time, CZE method for the direct and rapid determination of TIG and its separation from other components in intravenous infusion solution. The developed CZE method has several advantages over current chromatographic methods such as higher efficiency of separation within short analysis time, consumption of fewer quantities of chemicals and offering better resolution than HPLC. Moreover, three green spectrophotometric methods are also proposed for TIG determination that offer many advantages such as accuracy, precision, simplicity, specificity and facility of quantification and separation of the selected drug in infusion bags and pharmaceutical preparations without any techniques for extraction.

Simultaneous determination of Mometasone Furoate and salicylic acid in complex matrix using green analytical method

A green capillary zone electrophoretic method (CZE) has been developed and validated for the analysis of mometasone furoate (MF) and salicylic acid (SAL) simultaneously in synthetic mixtures and topical preparation (Elicasal® ointment) in a ratio of 1: 50 (MF: SAL). The proposed CZE method showed linear response for both MF and SAL in concentration ranges 0.2 – 40 μg/mL and 0.1 – 80 μg/mL, respectively. The detection and quantification limits for the assay of MF were 0.04 and 0.13 μg/mL, and of SAL were 0.03 μg/ mL and 0.1 μg/ mL, respectively. The suggested procedure is successfully used for the accurate and precise determination of the binary mixture in bulk powder and in Elicasal® ointment. The main advantages of the proposed method are being sensitive, selective, inexpensive and rapid with the use of fewer quantities of solvents and analytical reagents. The proposed method was validated according to ICH guidelines. Comparison between the proposed method and reported ones, using Green Analytical Procedure Index (GAPI) and the Eco-scale penalty points approach (PPs), shows that the developed method is a better eco-friendly method than the reported ones.

Analysis of bioactive flavonoid-O-glycosides in Saussurea mongolica Franch by capillary zone electrophoresis using ionic liquids as the additive

In this study, a capillary zone electrophoretic method, in which 1-alkyl-3-methylimidazolium-based ionic liquids (IL) was used as the additive, was established to separate and identify six bioactive flavonoid-O-glycosides in Saussurea mongolica Franch. In order to investigate the traits of IL in capillary electrophoresis (CE), the influences of the alkyl group, the anionic part and the concentration of IL were investigated and discussed. Optimum separation was achieved with 20 mM borate buffer at pH 9.00 containing 5 mg/mL 1-ethal-3-methylimidazolium tetrafluoroborate. The applied voltage was 15 kV and the capillary temperature was kept constant at 25°C. The relative standard deviations (RSD) of the migration time and the peak area of each peak for six replicate injections were 0.75%-1.45% and 3.18%-3.91%, respectively. Moreover, it was worth noticing that the mechanism of interaction between IL and analytes was investigated preliminarily.

Green stability-indicating capillary electrophoretic method for simultaneous determination of Lesinurad and Allopurinol in tablet dosage form: Degradation kinetics investigation

A binary mixture of Lesinurad (LES) and Allopurinol (ALP) is a newly marketed anti-gout combination where no stability indicating methods have been reported for its analysis. In this work, a simple, green stability indicating capillary zone electrophoretic method coupled with a diode array detector (CZE-DAD) has developed and validated for analyzing this mixture in their combined dosage form. Separation was achieved using fused silica capillary (55 cm × 50 μm id) using 50 mM borate buffer adjusted to pH 10 with 0.5 M NaOH. The linearity concentration ranges were 5–50 and 10–100 μg/mL for LES and ALP, respectively. The stability indicating ability of the proposed method was investigated by analyzing the two drugs after being subjected to several stress conditions as per ICH guidelines. The developed method was able to separate the two intact drugs from their degradation products formed under different stress conditions (acidic, basic, oxidation). In addition, the developed method has been applied to investigate the degradation kinetics of LES and ALP under acidic, basic and oxidative conditions. The degradation of the two drugs was found to follow pseudo-first order kinetics and degradation half-lives were also calculated for both drugs under different stress conditions. The developed CZE method is the first in the literature for determination of both LES and ALP in the presence of their related degradation products with high separation efficiency, minimum solvent consumption, enhanced method greenness and low operation cost. Thus, the proposed method is an efficient simple eco- friendly analytical tool for the routine analysis of LES and ALP in their combined dosage form in presence of their degradation products in quality control laboratories.

Validated capillary zone electrophoretic method for simultaneous analysis of benazepril in combination with amlodipine besylate and hydrochlorothiazide

In this work, a novel, simple, and quick capillary zone electrophoresis (CZE) method was proposed for simultaneous analysis of benazepril (BEN) with other co-administrated antihypertensive drugs, amlodipine besylate (AML) and hydrochlorothiazide (HCT), using a diode array detector (DAD). A fused silica capillary (78.5 cm total length, 70 cm effective length, and 75 μm id) was used in separation using a 40 mM phosphate buffer pH 7.5 as a running background electrolyte (BGE) under a positive potential of 30 KV, at a stable temperature of 25 °C for capillary during separation. Hydrodynamic injections were performed for 12 s at 50 mbar, and detection was performed at 210 nm for AML and BEN, at 225 nm for HCT, and at 232 nm for xipamide (XIP) added as an internal standard (IS). Separation of the three analyzed drugs and the IS was performed in less than 8 min. Migration times were 4.06, 5.23, 6.69, and 7.3 min for AML, HCT, BEN, and XIP, respectively. The findings proved that the proposed method was linear in the range of 10–80 μg/mL for all drugs with correlation coefficients >0.9994. The limit of detection (LOD) values of AML, HCT, and BEN were 1.004, 1.224, and 0.896 μg/mL, respectively, whereas the limit of quantification (LOQ) values were 3.124, 3.727, and 2.749 μg/mL for the cited drugs, respectively. Peak identity and purity were confirmed by DAD. The developed CZE method was applied for the analysis of the three antihypertensive drugs successfully in their combined pharmaceutical tablets, and it can be used for the quality control of single-pill combination (SPC) samples of these drugs in short time.

Simple and rapid liquid chromatographic and electrophoretic methods for phenol quantification and its stability in tuberculin purified protein derivative preparations

Phenol is commonly used as an antimicrobial agent with an initial concentration of 0.35% (w/v) in injectable diluted tuberculin purified protein derivative (TPPD) solution. The anti-microbial action of phenol in TPPD is directly concentration dependent. Furthermore, high phenol content (>0.5%) may have a negative effect on the stability and clinical effectiveness of TPPD solution. Therefore, simple, rapid and reliable reversed phase liquid chromatographic (RPLC) and capillary zone electrophoretic (CZE) methods were firstly developed and validated for phenol quantification in Connaught tuberculin (CT68) PPD diluted preparations at 5 TU per test dose of 0.1 mL. In RPLC, the elution was carried out by 80% (v/v) ACN mixed with 20% (v/v) phosphate buffer containing 0.05% (v/v) triflouroacetic acid (pH 3.2) at 0.2 mL min−1 flow rate and 20.0 °C column temperature. In addition, phenol was separated from tuberculin (CT68) protein with a resolution of (R = 2.81) and was quantified within 3 min.In CZE, the migration of phenol was performed by 50 mmol L−1 borate buffer (pH 9.8) at −20 kV applied voltage and 25.0 °C capillary temperature. Furthermore, excellent linearity was achieved within 0.17–0.53% (w/v) for the phenol content with coefficients of determination (r2) higher than 0.9995. Moreover, the detection and quantification limits were found to be 0.046 & 0.153% and 0.051 & 0.171% (w/v) with RPLC and CZE respectively. Additionally, the intraday precision (RSD%, n = 9) was ranged between 0.18 and 0.39 and 0.33–54 with RPLC and CZE respectively. Moreover, the interday precision (RSD%, n = 27) was varied between 2.06 and 2.99 and 2.25–3.40 by RPLC and CZE, respectively. Furthermore, the obtained mean recoveries were ranged between 91.32 and 107.51% with RPLC and 90.71–108.92% with CZE. In addition, the effect of different storage temperatures at 4, 25 and 37 °C over storage periods of 2, 7, 14, 21 and 30 days was also studied on the TPPD product. The obtained results have revealed that the phenol content was effectively decreased about 37% of its original content after 30 days at storage temperatures of 25 and 37 °C. However, the phenol content did not change and was stable up to 21 days at storage temperature of 4 °C. Therefore, the simple and rapid proposed analytical methods could be used for a rapid expiry investigation of TPPD products based on phenol quantification, as a marker.

Application of capillary electrophoresis to the separation of rhenium complex of 1,2,3-trihydroxybenzene

A capillary zone electrophoretic method has been developed for a separation of a reaction mixture of a rhenium complex. The rhenium complex was synthesized in a reaction of a rhenium precursor and 1,2,3-trihydroxybenzene in acetonitrile with triethylamine addition. The capillary electrophoretic method has been used for the separation in borate and phosphate buffer (pH 6.30–11.80). All components in the reaction mixture (unreacted precursor, ligand, and final rhenium complex) have been determined by capillary zone electrophoresis with UV–Vis detection in an aqueous running electrolyte within 10 min. Dependencies of effective electrophoretic ion mobility on the pH value have been determined for the ligand, unreacted precursor, and final complex in both electrolytes.

A Validated Capillary Electrophoretic Method for the Determination of Olopatadine and Its Application to a Pharmaceutical Preparation of Eye Drops.

A validated rapid and sensitive capillary zone electrophoretic method for the determination of olopatadine hydrochloride (OLO) is described. Optimum conditions were found: 20 mmol/L sodium tetraborate buffer, acetonitrile 15% (v/v), 10 mmol/L NaCl at pH 9.5, with 25 kV of applied potential, injection time of 10 s at 5 × 103 N/m2, at a wavelength of 205 nm, and fixed temperature of 30°C. The calibration curve was linear in the range of 1.13 × 10-5 mol/L (4.22 μg/mL) to 5.65 × 10-5 mol/L (21.12 μg/mL), with R = 0.9995 for interday precision. LOD and LOQ values were 1.58 × 10-6 (0.58 μg/mL) and 4.78 × 10-6 mol/L (1.75 μg/mL), respectively. Precision values were 1.10-1.97% for intraday and 1.41% for interday RSDs. Accuracy was tested by preparing a synthetic mixture whose composition was similar to the pharmaceutical preparation for Patanol. The RSDs of the recovery values (98.2%) were between 0.42 and 0.65% and the amount of OLO found was 1.09 mg/mL. The result was within the requirements of USP 31-NF 26. Therefore, this validated method is suggested for routine analysis for the determination of OLO in laboratories.

Development and validation of a capillary zone electrophoretic method for rapid and sensitive determination of galanthamine: Application in plant and pharmaceuticals

Galanthamine is a second-generation cholinesterase inhibitor that has begun to be used in the treatment of Alzheimer's disease. In the presented research, a simple, accurate, precise and cost-effective capillary zone electrophoretic (CZE) method was used for the qualitative and quantitative estimation of Galanthamine from bulbs, leaves and fringes of Leucojum aestivum L. (summer snowflake) grown in Turkish habitats (Black Sea Region) and pharmaceutical dosage forms by capillary zone electrophoresis with direct UV detection form. Ultrasonic assisted extraction (UAE) and response surface methodology (RSM) were used to estimate optimum experimental conditions on the content extraction of Leucojum aestivum L. Metoprolol was used as a suitable internal standard. A linear relationship between the ratio and concentrations of Galanthamine in the range of 0.25μgmL−1–15.00μgmL−1was determined with a regression coefficient of 0.9996, for which the limit of detection (LOD) and limit of quantitation (LOQ) were 0.027 and 0.081μgmL−1, respectively. The high percentage recovery results showed that the matrix effect did not influence the developed method for analysis of pharmaceutical preparations. Validation parameters were carried out according to the guidelines of the International Conference for Harmonization (ICH). This method also allows for a number of cost- and time-saving benefits and can be readily employed for the analysis of plants and pharmaceutical formulations. The method can be used in industries for the determination of Galanthamine to analyze the quality of extraction and formulation without interference.

Simultaneous Determination of Quercetin, Rutin, Naringin, and Naringenin in Different Fruits by Capillary Zone Electrophoresis

A fast and reliable capillary zone electrophoretic (CZE) method has been developed for the simultaneous determination of four fruit flavonoids using photodiode array (PDA) detector. The effects of CE parameters including concentration and pH of the running buffer, voltage, and injection time were optimized. Under the optimized conditions, all flavonoids were well determined in a 10 mM borate buffer of pH 8.5 within 10 min at an applied voltage of 25 kV. Naringin, naringenin, and quercetin were found to have linear response in the range of 3.12–200 μg/mL whereas rutin’s response was linear from 6.25 to 200 μg/mL. LOD was found to be 0.406, 0.314, 0.582, and 0.333 μg/mL and LOQ 1.355, 1.046, 1.941, and 1.11, respectively. Relative standard deviations (RSD) were found to be less than 3 % for both migration time and peak height which shows long-term stability and good reproducibility of the developed method. The method was successfully applied for the simultaneous determination of flavonoids from various fruit juice samples.

Validation of Capillary Zone Electrophoretic Method for Evaluating Monoclonal Antibodies and Antibody-Drug Conjugates

Validation of Capillary Zone Electrophoretic Method for Evaluating Monoclonal Antibodies and Antibody-Drug Conjugates

A capillary electrophoretic–mass spectrometric method for the assessment of octreotide stability under stress conditions

A capillary zone electrophoretic-electrospray ion trap mass spectrometric method has been developed to assess the stability and pathways of degradation of the cancer therapeutic octapeptide, octreotide. As a somatostatin analogue, octreotide contains a single disulphide bond linking Cys2–Cys7 with the structure of ▪. Resolution of octreotide from its degradation products was achieved using a capillary zone electrophoretic method with bare fused silica capillaries, a 10mM ammonium formate buffer, pH 3.20, at 25°C and an applied voltage of 25kV. An ion trap low energy collision induced dissociation procedure was applied for the characterization of the chemical structures of the degradation products derived from an acidic, alkaline, neutral and thermal solution treatment of octreotide. The results so obtained indicated that linear octreotide degradation products were formed under acidic and alkaline conditions, due to the hydrolysis of a ring amide bond and a hitherto unknown desulfurization of the Cys–Cys disulfide bond, respectively. Degradation under neutral conditions occurred via cleavage of the exocyclic N-((2R,3R)-1,3-dihydroxybutan-2-yl) amide bond which also preceded the ring amide hydrolysis under acidic conditions. The developed method was further successfully applied to assess the kinetics of these octreotide degradations. Overall, this method is suitable for the rapid and precise assessment of the stability and quality control of octreotide as a synthetic peptide-based pharmaceutical product, and has led to the discovery of a new Cys–Cys disulfide degradation pathway.

Sensitive Residue Analysis of Quinolones and Sulfonamides in Aquatic Product by Capillary Zone Electrophoresis Using Large-Volume Sample Stacking with Polarity Switching Combined with Accelerated Solvent Extraction

A simple and sensitive capillary zone electrophoretic method for the residue determination of lomefloxacin, enoxacin, sarafloxacin, enrofloxacin, sulfadiazine, sulfamethoxydiazine, and sulfadimethoxypyrimidine was developed. Accelerated solvent extraction with acetonitrile as solvent at 80 °C and 10.3 MPa was used for sample preparation. On-column preconcentration using large-volume sample stacking with polarity switching was applied for sensitivity enhancement. The standard curves for the determination of the seven residues have good linearity (r > 0.999). The method limits of quantification (LOQs) were 13.2–20 μg kg−1 for the quinolones and 8.0 μg kg−1 for the sulfonamides. Intraday and inter-day precisions (RSDs) at 100 μg kg−1 level were 1.4–4.1 and 2.3–4.7 %, respectively. The residue determination of the quinolones and sulfonamides in aquatic products was achieved. Their average recoveries for three spiked levels (50, 100, and 500 μg kg−1) were 85.4–95.7 % with the RSD of 1.1–4.7 % for shrimp sample and 84.3–94.8 % with the RSD of 1.4–4.5 % for sardine sample. The proposed method provides a rapid and simple extraction procedure, satisfactory repeatability, and reproducibility, as well as high accuracy, and can permit the routine detection of the studied drug residues in aquatic product at the content below or above the MRL.

Cyclodextrine screening for the chiral separation of carvedilol by capillary electrophoresis.

Carvedilol is administered as a racemic mixture of the R(+)- and S(-)-enantiomers, although it was demonstrated that the two enantiomers exhibit different pharmacological effects and stereoselective pharmacokinetics. The aim of this study was the evaluation of several native and derivatized cyclodextrines as chiral selectors for the separation of carvedilol enantiomers. Stereoselective interactions were observed with four cyclodextrines (β-CD, hydroxypropyl-β-CD, randomly methylated β-CD and sulfobuthyl ether- β-CD). The effects of CD concentration, pH value and composition of the background electrolyte, capillary temperature, running voltage and injection parameters have been investigated. The method was validated for precision of peak-area response, linearity range and limits of detection and quantification. An efficient stereoselective capillary zone electrophoretic method was developed for the determination of carvedilol enantiomers using a simple 25 mM phosphate buffer at a pH = 2.5 and 10 mM β-CD as chiral selector, resulting in baseline separation of the two enantiomers with sharp peaks and relatively short analysis time. Highly satisfactory results were obtained from the analysis of carvedilol from tablets, indicating that the method is suitable for routine analysis of carvedilol in pharmaceutical products.

Fast and Simultaneous Analysis of Combined Anti-Diabetic Drugs by Capillary Zone Electrophoresis.

A fast capillary zone electrophoretic method with photodiode array detection (CZE-PAD) was established and validated for assays of commonly prescribed anti-diabetic drugs [metformin (MET), glibenclamide (GBM) and gliclazide (GCZ)] in 13 samples including raw material, single and combined tablets. CZE optimization revealed baseline separation of the analytes (Rs > 5.39) in 8 min, in 50 mM borate buffer (pH 9.0), using a capillary with an effective length of 56.0 cm and an inner diameter of 50 µm, a voltage of 20 kV, a temperature of 25°C and a detection wavelength at 210 nm. The method provides excellent linearity, precision (%RSDs < 1.90%), recovery (99.8-101.0%) and low detection and quantitation limits (<4 and 12 µg/mL, respectively). The procedure was fast (seven samples per hour) and cost effective, since no organic solvent, sample pre-treatments or clean-up procedures were required. Importantly, the method was accurate, sensitive and reliable for routine quality control of MET, GBM and GCZ in pharmaceutical products both in single and combined formulations.

A Simple Stability Indicating CZE Method for the Analysis of Octreotide Acetate

A simple stability indicating capillary zone electrophoretic method was developed and validated for the analysis of octreotide acetate (OCT-Ac). The best separation was achieved by bare fused silica capillaries (50 μm i.d.; 65.5 cm total and 57.0 cm effective length), phosphate buffer (pH = 3.25; 50 mM), at 32.5 °C. The samples were injected using 50 mbar for 5 s and subjected to the applied voltage of 27.5 kV for separation. The detection was carried out using a PAD at a wavelength of 195 nm. For improving the repeatability of the method, l-histidine was applied as an internal standard. According to the validation results, the method was linear in the concentration range of 3.30–400 μg mL−1 (correlation coefficient of 0.9996) with a limit of detection of 1.08 μg mL−1 and a limit of quantification of 3.30 μg mL−1; accuracy of the method was between 100.4 ± 0.2 and 101.1 ± 0.2 %; intra-assay precision was 0.5–2.6 % and intermediate precision was 1.3–3.2 %. The proposed method was successfully applied for the quantification of OCT-Ac in both a pharmaceutical formulation and force-degraded samples and for the detection and separation of degradation products; besides, the obtained results were used for the evaluation of the degradation kinetics of OCT-Ac under different stress conditions. So, it is concluded that the developed method could be employed as a simple, accurate and precise stability-indicating method in quality control laboratories to assess the quantity and stability of OCT-Ac pharmaceutical products.

Determination of cetirizine and its impurities in bulk and tablet formulation using a validated capillary zone electrophoretic method

A stability indicating capillary electrophoretic method for separation and determination of cetirizine dihydrochloride and its major impurities in bulk and a tablet dosage form was developed. The electrophoretic separation was performed in an uncoated fused-silica capillary (75 cm × 50 μm i.d.) using 75 mM sodium phosphate (pH 2.8) as background electrolyte, with an applied voltage of +25 kV at 25°C and UV detection at 230 nm. Fexofenadine was used as internal standard. The proposed method was found selective for determination of the main drug and its major impurities. The regression data obtained from the calibration plots indicated linear relationship (r2 = 0.998) over the concentration range of 40–240 μg/mL of cetirizine. Repeatability and reproducibility of the method, assessed as intra-day and inter-day variation and expressed as RSD (%), were 1.3 and 2.6, respectively. Stress tests on cetirizine under acidic, basic, oxidative and heat incubating at 80°C conditions revealed that no major compound was formed under the applied conditions and the proposed CE method is applicable for stability studies on cetirizine. Then, the method was successfully applied to the determination of cetirizine in bulk and a tablet dosage form.

Simultaneous determination of aliskiren hemifumarate, amlodipine besylate, and hydrochlorothiazide in their triple mixture dosage form by capillary zone electrophoresis

A novel, specific, reliable, and accurate capillary zone electrophoretic method was developed and validated for the simultaneous determination of aliskiren hemifumarate, amlodipine besylate, and hydrochlorothiazide in their triple mixture dosage form. Separation was carried out in a fused-silica capillary (57.0 cm total length and 50.0 cm effective length, 75.6 μm internal diameter) by applying a potential of 17 kV and a running buffer consisting of 40 mM phosphate buffer at pH 6.0 with UV detection at 245 nm. The method was suitably validated with respect to specificity, linearity, LOD, and LOQ, accuracy, precision, and robustness. The method showed good linearity in the ranges 1-10, 2.5-25, and 30-300 μg/mL with LODs of 0.11, 0.33, and 5.83 μg/mL for amlodipine besylate, hydrochlorothiazide, and aliskiren hemifumarate, respectively. The proposed method was successfully applied for the analysis of the studied drugs in their coformulated tablets. The results of the proposed method were statistically compared with those obtained by the RP-HPLC reference method revealing no significant differences in the performance of the methods regarding accuracy and precision.

Simultaneous analysis of gemifloxacin mesylate and its main synthetic impurity by an optimized capillary zone electrophoretic method

A simple and rapid stability indicating capillary zone electrophoretic (CZE) method was validated for the simultaneous determination of gemifloxacin mesylate (GFM) and its main synthetic impurity. The method was performed with a fused-silica capillary (50 μm i.d.) maintained at 30 °C. The background electrolyte consisted of 25 mM borate buffer (pH 10) and the separation was achieved applying 30 kV. The samples were injected hydrodynamically (6 s at 50 mbar) and detection was done at 220 nm. The procedure was validated by specificity, limit of detection (LOD), limit of quantification (LOQ), linearity, accuracy, precision and robustness. Degradations were performed in 0.1 M HCl, 0.01 M NaOH, 30% H2O2, moist heat at 60 °C and exposure to UV-A radiation to show the specificity and stability-indicating capability. Otherwise the excipients did not interfere with the quantitation of GFM. The method was linear for GFM (20.0–80.0 μg mL−1) and its synthetic impurity (3.0–20.0 μg mL−1). LOD and LOQ were 1.0 and 3.0 μg mL−1, respectively, for synthetic impurity. The results of precision and accuracy showed values that agreed with the literature and the Plackett–Burman experimental design applied confirmed the robustness. The proposed method was used for the quantitative analysis of GFM and its synthetic impurity.