Stability-indicating capillary electrophoresis method for the simultaneous determination of metformin hydrochloride,saxagliptin hydrochloride,and dapagliflozin in pharmaceutical tablets

A capillary electrophoretic method coupled to a diode array detector (CE-DAD) was developed and validated for the simultaneous determination of metformin hydrochloride (MET), the dipeptidyl peptidase-4 (DPP-4) inhibitor saxagliptin hydrochloride (SAX), and the sodium glucose co-transporter (SGLT 2) inhibitor dapagliflozin (DAP). The proposed method was used for the determination of these drugs in binary antidiabetic combinations namely, SAX/MET, combination I, DAP/MET, combination II, and SAX/DAP, combination III. CE separation was performed on a fused silica capillary with background electrolyte consisting of 30?mM phosphate buffer (pH 6.0) with a high voltage of 30?kV, a pressure of 20 mbar, and an injection time of 40?s. The compounds were detected at 203?nm for SAX/DAP and 250?nm for MET. The method was linear in the concentration range of 10–200?µ?g/mL (SAX), 1.25–50?µ?g/mL (DAP), and 7.5–1000?µ?g/mL (MET). Full validation of the proposed method was performed as per the ICH guidelines. The obtained errors and deviation values did not exceed 2% assessing good accuracy and precision, respectively. The stability-indicating potential of the proposed method was proved under different stress-degradation conditions. The proposed method was successfully applied to the analysis of the three binary combinations in their tablets.     

A green capillary zone electrophoresis method for the simultaneous determination of piperacillin,tazobactam and cefepime in pharmaceutical formulations and human plasma

A green, novel, rapid, accurate and reliable capillary zone electrophoresis method was developed and validated for the simultaneous determination of piperacillin, tazobactam and cefepime in pharmaceutical preparations. Separation was carried out using fused silica capillary (50 µm i.d. × 48.6 cm and 40.2 cm detection length) and applied potential of 20 kV (positive polarity) and a running buffer containing 15 m m sodium borate buffer adjusted to pH 9.3 with UV detection at 215 nm. Amoxicillin was used as an internal standard. The method was suitably validated according to International Conference on Harmonization guidelines. The method showed good linearity in the ranges of 10–100, 20–400 and 10–400 µg/mL with limits of quantitation of 1.87, 3.17 and 6.97 µg/mL and limits of detection of 0.56, 0.95 and 2.09 µg/mL for tazobactam, piperacillin and cefepime, respectively. The proposed method was successfully applied for the analysis of these drugs in their synthetic mixtures and co‐formulated injection vials. The method was extended to the in vitro determination of the two drugs in spiked human plasma. It is considered a ‘green’ method as it consumes no organic solvents. Copyright © 2015 John Wiley & Sons, Ltd.     

Quantitative separation of oxytocin,norfloxacin and diclofenac sodium in milk samples using capillary electrophoresis

A simple, sensitive and rapid method has been developed for simultaneous separation and quantification of three different drugs: oxytocin (OT), norfloxacin (NOR) and diclofenac (DIC) sodium in milk samples using capillary electrophoresis (CE) with UV detection at 220 nm. Factors affecting the separation were pH, concentration of buffer and applied voltage. Separation was obtained in less than 9 min with sodium tetraborate buffer of pH 10.0 and applied voltage 30 kV. The separation was carried out from uncoated fused silica capillary with effective length of 50 cm with 75 µm i.d. The carrier electrolyte gave reproducible separation with calibration plots linear over 0.15–4.0 µg/mL for OT, 5–1000 µg/mL for NOR and 3–125 µg/mL for DIC. The lower limits of detection (LOD) were found to be 50 ng/mL for OT, and 1 µg/mL for NOR and DIC. The method was validated for the analysis of drugs in milk samples and pharmaceutical preparations with recovery of drugs within the range 96–100% with RSD 0.9–2.8%. Copyright © 2009 John Wiley & Sons, Ltd.     

Electrochemical Determination of Carbofuran in Tomatoes by a Concanavalin A (Con A) Polydopamine (PDA)-Reduced Graphene Oxide (RGO)-Gold Nanoparticle (GNP) Glassy Carbon Electrode (GCE) with Immobilized Acetylcholinesterase (AChE)

A new biosensor method was developed to determine residual carbofuran in tomatoes in a rapid and convenient fashion based on immobilizing acetylcholinesterase (AChE) on an electrode modified by concanavalin A (Con A)/polydopamine (PDA)-reduced graphene oxide (RGO)-gold nanoparticle (GNP) nanocomposites. The specific binding between Con A and AChE was investigated by the Ellman method and cyclic voltammetry (CV). The synthesis of nanocomposites was monitored by ultraviolet-visible absorption spectroscopy, scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The results showed that, due to the specific binding and good electrical conductivity, the biosensor had 2.2 times higher bioactivity, leading to high sensitivity with a low Michaelis constant of 0.10?mM. Parameters that affect the response of the biosensor, such as the pH, enzyme loading, ionic concentration, and inhibition time, were optimized. When used for the detection of carbofuran, this biosensor showed a wide range of applicability from 5?µg/kg to 40?µg/kg with a detection limit of 0.012?µg/kg. In addition, the biosensor demonstrated good recovery values of 101% and 90% for 10?µg/kg and 100?µg/kg of the analyte, good stability, high repeatability, and a rapid detection time of 20?min for carbofuran in tomatoes, which provides significant advantages for future analysis.     

高效毛细管电泳大体积样品堆积在线富集法测定蒲公英中阿魏酸、绿原酸和咖啡酸

采用大体积样品堆积(LVSS)在线富集模式,建立了高效毛细管电泳(HPCE)测定蒲公英中阿魏酸、绿原酸和咖啡酸含量的方法。主要考察了在毛细管区带电泳(CZE)分离模式下,缓冲液的pH和浓度对分离效果的影响,以及在LVSS在线富集模式下,进样时间对富集效果的影响。在最优条件下阿魏酸、绿原酸和咖啡酸可在12 min内得到分离,3个成分在0.5~25.0μg/mL浓度范围内均有较好的线性关系(r2=0.999),平均加样回收率分别为104.9%,98.0%和100.1%,RSD(n=6)分别为3.6%,2.6%和1.0%。定量限(S/N=10)分别为0.10,0.10和0.03μg/mL,检出限(S/N=3)分别为0.03,0.03和0.01μg/mL。相对于常规CZE模式,本方法的富集效果倍数为17~19倍。建立的方法可用于蒲公英的日常检测与质量控制。     

Direct Determination of Glyphosate in Environmental Waters Using Capillary Electrophoresis with Electrospray Condensation Nucleation Light Scattering Detection

An electrospray condensation nucleation light scattering detector (ESI-CNLSD) was coupled with capillary electrophoresis (CE) for analysis of glyphosate, a chemical of agricultural interest, which is otherwise difficult to detect owing to its lack of chromophores or fluorophores. To reduce the absorption of glyphosate on the CE capillary and to reduce the separation time, an N-cetyltrimethylammonium bromide (CTAB) pre-rinsing CE method was developed here. The protocol consisted of 15 min pre-rinsing of the capillary before analysis with CTAB solution and 5 min with ammonium acetate buffer at pH 2.8. The capillary inner wall coating established by this treatment lasted up to 10 h without bleeding to interfere with CNLSD signal. Calibration data were linear over two orders of magnitude, the instrument detection limit was 0.06 µg/mL and the method detection limit was 0.2 µg/mL. The method was applied to the analysis of local (rural area) lake water and commercial herbicide samples.     

Improved determination of 5-fluorouracil and its prodrug tegafur in pharmaceuticals by large-volume sample stacking in CE

On-line determination of the anti-tumor drug 5-fluorouracil (5-FU) and its prodrug, tegafur (TF) was achieved for the first time by capillary electrophoresis with large-volume sample stacking (CE-LVSS). The optimal electrophoretic buffer consisted of 30 mM phosphate buffer at pH 8.0. Without the LVSS procedure, the limits of detection (LOD) were 600.5 ng/mL and 771.4 ng/mL for 5-FU and TF, respectively. With the LVSS procedure, the sensitivity was significantly improved by about two orders of magnitude (the LODs of 5-FU and TF were decreased to 7.9 ng/mL and 6.5 ng/mL, respectively). The %RSD was less than 5%. This method compared favorably with other reported techniques and was applied successfully to the quantitative analysis of anti-tumor drugs in commercial injection preparations. The results show that the method is simple, fast (less than 3 min), highly selective, and sensitive.     

Separation and determination of six catechins in tea by pressurized capillary electrochromatography

An efficient pressurized capillary electrochromatography (pCEC) method has been successfully developed for the determination of six catechins in tea. The separation was performed on a reversed-phase EP-100-20/45-3-C18 capillary column (total length of 45?cm, effective length of 20?cm, diameter of 100?μm, ODS packing inside for 3?μm). The mobile phase ratio of organic phase, the concentration of phosphate buffer and sodium heptanesulfonate, separation voltage, and other experimental conditions were investigated and optimized. The mobile phase was 15?mM NaH₂PO₄ and 12?mM sodium heptanesulfonate (pH 3.0)/methanol (64:36) at a flow rate of 0.04?mL/min. Under optimal conditions including applied voltage of ?4?kV and a UV detection wavelength of 230?nm, the six catechins in the tea were well separated. The calibration curves for the analytes had good linearity in the range of 8.02?μg/mL–202.13?μg/mL with a correlation coefficient of 0.9928–0.9997. The limits of detection (LOD) for the six catechins were 4.62?μg/mL–11.63?μg/mL (S/N?=?3). The recoveries of the six catechins were 96.2%–108.4% with a relative standard deviation (RSD) between 0.78% and 4.51%. The method has been used for the determination of six catechins in tea samples with good results.     

Capillary electrophoresis with LED-induced native fluorescence detection for determination of isoquinoline alkaloids and their cytotoxicity in extracts of Chelidonium majus L

In this study, we introduced a simple and sensitive method of capillary electrophoresis with ultraviolet light-emitting diode-induced native fluorescence (UV-LEDIF) detection for the determination of isoquinoline alkaloids in extracts of Chelidonium majus L. Samples were extracted with acidic methanol and the extracts were directly analysed by CE. Simultaneous determination of protopine, chelidonine, coptisine, sanguinarine, allocryptopine, chelerythrine and stylopine was performed in 20mM phosphate buffer (pH 3.1). The baseline separation of these alkaloids was finished within 20 min. As these alkaloids have native fluorescence, they were directly detected using the commercially available UV light emitting diode without troublesome fluorescent derivatisation. Satisfactory LOD values were obtained for the studied compounds considering their appearance in natural extracts. Lower limits of detection were 0.05 μg/mL for protopine, 0.06 μg/mL for stylopine and allocryptopine, 0.07 μg/mL for chelidonine, 0.22 μg/mL for sanguinarine, 1.7 μg/mL for chelerythrine and 5.5 μg/mL for coptisine. The developed method was successfully applied to determine the contents of seven alkaloids in the aerial parts of Chelidonium majus L, which varied from 0.025 to 0.763% (w/w). Also, to demonstrate the potential of the proposed CE method, an estimation of the cytotoxic properties of selected Celandine alkaloids in a natural extract was carried out.     

Analysis of carbamazepine and its five metabolites in serum by large-volume sample stacking–sweeping capillary electrophoresis

This study establishes a method, using different buffer conductivities and large-volume sample stacking (LVSS)–sweeping capillary electrophoresis, for analysis of carbamazepine (CBZ) and its five metabolites in serum. The capillary (50/60 cm) was filled with a high concentration of background electrolyte (150 mM phosphate, pH?3.5, containing 15 % methanol), followed by a large volume of samples (10 psi, 20 s) with low-concentration buffers (5 mM phosphate, pH?3.5, with 5 % methanol). When high voltage was applied (?20 kV), the sodium dodecyl sulfate (SDS) started to sweep the analytes to an outlet. Meanwhile, the analytes decelerated at the boundary between low- and high-conductivity buffers. Finally, a narrow sample zone was formed. The procedure of sweeping and separation was simultaneously carried out by a sweeping buffer (150 mM phosphate, pH?3.5) with 15 % methanol and 50 mM SDS added, and the detection was performed by UV at 214 nm. The method was validated for linearity (r?≧?0.997), precision, and accuracy. The calibration curves were established for CBZ and its five metabolites between 0.03–25 and 0.03–3 μg/mL. The limits of detection (S/N?=?3) were 0.01 μg/mL for each analyte. Compared with simple MEKC (0.5 psi, 5 s), this system can improve the sensitivity about 300-fold. Finally, this method was successfully applied to five patients, who had taken 200 mg CBZ daily, and CBZ levels were found to be from 3.72 to 5.82 μg/mL.

Simultaneous separation and analysis of camptothecin alkaloids in real samples by large‐volume sample stacking in capillary electrophoresis

Large‐volume sample stacking (LVSS) is commonly used as an effective online preconcentration method in capillary zone electrophoresis (CZE). In this paper, the method LVSS combined with CZE has been proposed to analyze camptothecin alkaloids. Optimum separation can be achieved in the following conditions: pH 9.0; 25mm borate buffer containing 20 mm sulfobutylether‐β‐cyclodextrin and 20 mm ionic liquid 1‐ethyl‐3‐methyllimidazole l ‐lactate; applied voltage 20 kV; and capillary temperature 25 °C. The LVSS was optimized as hydrodynamic injection 4 s at 5.0 psi and the polarity switching time was 0.17 min. Under the above conditions, the analytes could be separated completely in <20 min and the detector response was increased compared with conventional hydrodynamic injection. The limits of detection were between 0.20 and 0.78 μg/L. A good linearity was obtained with correlation coefficients from 0.9991 to 0.9997. The recoveries ranged from 97.72 to 103.2% and the results demonstrated excellent accuracy. In terms of the migration time and peak area, the experiment was reproducible. The experimental results indicated that baseline separation can be obtained and this method is suitable for the quantitative determination of camptothecin alkaloids in real samples.     

Applying green analytical chemistry for development and validation of RP-HPLC stability indicating assay method for estimation of fenoverine in bulk and dosage form using quality by design approach

A green and robust reverse-phase liquid chromatographic method has been developed for the determination of fenoverine (FEN), by applying combined principles of green analytical chemistry and quality by design approaches on a Spherisorb C18 column (150?×?4.6?mm, 3?µm) with UV detection at 262?nm. A two level fractional factorial design (2^^7-3) Res IV was used for screening of influential chromatographic factors. The critical method parameters actively affecting critical quality attributes (CQAs) were identified and further optimized using Box–Behnken design. The predicted optimum assay conditions comprised of methanol and ammonium acetate buffer 20?mM, in an extent of 81:19% v/v individually having a flow rate of 1.0?mL/min with a column oven temperature of 33°C. The drug was stressed in hydrolytic, oxidative, reductive, thermal, and photolytic conditions. The developed method was validated successfully. The detector response was linear in the concentration of 0.5–160?µg/mL with a limit of detection (LOD) and limit of quantitation (LOQ) as 0.1 and 0.3?µg/mL, respectively. The % recovery was found to be 99.7%. The analytical method volume intensity value for developed method was 45?mL and the environment assessment tool (EAT) score was 41.07. The method is simple, environmentally benign, rapid, and robust for the determination of FEN in bulk and in its dosage form.     

Effects of the Interaction of Rifamycin SV with Serum Albumins on the Resonance Rayleigh Scattering Spectra and Their Analytical Application

In pH 4.5–4.8 Britton‐Robinson buffer solution, rifamycin SV (i.e. rifamycin sodium) can react with serum albumin such as human serum albumin (HSA) and bovine serum albumin (BSA) to form macromolecular complexes by electrostatic attraction and hydrophobic force. As a result, the resonance Rayleigh scattering (RRS) of the drug was enhanced remarkably and the RRS peaks were at 374 and 552 nm. The enhancement of RRS (ΔI) is directly proportional to the concentration of HSA or BSA. The linear ranges and the detection limits are 0.03–6.0 µg/mL and 9.0 ng/mL for HSA, and 0.01–8.0 µg/mL and 2.0 ng/mL for BSA, respectively. In this work, a sensitive, selective, simple and fast method for the determination of trace amounts of serum albumin by RRS technique has been developed, which was applied to the determination of serum albumin in the synthesized samples and human urine samples with satisfactory results.     

Enhanced Specificity and Sensitivity for the Determination of Nickel(II) by Square-wave Adsorptive Cathodic Stripping Voltammetry at Disposable Graphene-modified Pencil Graphite Electrodes

Chemical sensors relying on graphene-based materials have been widely used for electrochemical determination of metal ions and have demonstrated excellent signal amplification. This study reports an electrochemically reduced graphene oxide (ERGO)/mercury film (HgF) nanocomposite-modified pencil graphite electrode (PGE) prepared through successive electrochemical reduction of graphene oxide (GO) sheets and an in situ plated HgF. The ERGO-PG-HgFE, in combination with dimethylglyoxime (DMG) and square-wave adsorptive cathodic stripping voltammetry (SW-AdCSV), was evaluated for the determination of Ni²⁺ in tap and natural river water samples. A single-step electrode pre-concentration approach was employed for the in situ Hg-film electroplating, metal-chelate complex formation, and non-electrolytic adsorption at –0.7 V. The current response due to nickel-dimethylglyoxime [Ni(II)-DMG₂] complex reduction was studied as a function of experimental paratmeters including the accumulation potential, accumulation time, rotation speed, frequency and amplitude, and carefully optimized for the determination of Ni²⁺ at low concentration levels (μg?L^?1) in pH 9.4 of 0.1 M NH₃–NH₄Cl buffer. The reduction peak currents were linear with the Ni²⁺ concentration between 2 and 16?μg?L^?1. The limits of detection and quantitation were 0.120?±?0.002?µg?L^?1 and 0.401?±?0.007?µg?L^?1 respectively, for the determination of Ni²⁺ at an accumulation time of 120?s. The ERGO-PG-HgFE further demonstrated a highly selective stripping response toward Ni²⁺ determination compared to Co²⁺. The electrode was found to be sufficiently sensitive to determine metal ions in water samples at 0.1?µg?L^?1, well below the World Health Organization standards.     

Chemometrically assisted optimization and validation of a new HPLC method for the determination of paliperidone in pharmaceuticals

Paliperidone is an antipsychotic drug, which is used for the acute and maintenance treatment of schizophrenia. In this study, a new method was developed for the determination of Paliperidone in its extended-release tablets. Face-centered central composite design was applied for optimization of the method. Factors were decided as acetonitrile content, pH of the mobile phase and buffer concentration through preliminary studies. Optimal flow rate (1?mL/min), column temperature (35°C) and internal standard (Bupropion) were also determined during preliminary studies. Retention factors and tailing factors of Paliperidone and Bupropion were selected as responses. Derringer’s desirability function was applied for simultaneously optimization of these four responses. Optimal conditions were predicted as phosphate buffer (pH:3, 23?mM): acetonitrile (76:24, v:v). Developed method was validated in terms of linearity, detection and quantification limits, accuracy, precision, specificity and robustness. Method was found linear in the concentration range of 0.125-100?µg/mL. Mean equation of the calibration curve was y?=?0.0807 x - 0.0102 (R²?=?0.9999). Accuracy and precision of the method was evaluated with recovery values (98-102%) and relative standard deviation values (<2%), respectively. All other parameters were found acceptable. The method was successfully applied for the determination of Paliperidone in its extended-release tablets.     

Simultaneous determination of active ingredients in ethnomedicine Gaultheria leucocarpa var. yunnanensis and its medicinal preparation by capillary electrophoresis with electrochemical detection

A simple and rapid capillary electrophoresis (CE) with electrcochemical detection (ED) method has been established for the simultaneous determination of seven active ingredients in the stems and roots of Gaultheria leucocarpa var. yunnanensis and its medicinal preparation, including (+)-catechin, rutin, gentisic acid, vallinic acid, salicylic acid, quercetin, and protocatechuic acid. The effects of working potential, pH, and concentration of running buffer, separation voltage, and injection time on CE-ED are systematically investigated. Under the optimum conditions, the seven analytes could be completely separated within 23 min in a borax running buffer (pH 8.7). A good linear relationship is obtained over three orders of magnitude with detection limits (signal-to-noise ratio=3) ranging from 5x10(-8) g/mL to 3x10(-7) g/mL for the analytes. The proposed method is successfully used in the analysis of real samples after a relatively simple extraction procedure, and the assay results are satisfactory.     

Simultaneous determination of ofloxacin and ornidazole in pharmaceutical preparations by capillary zone electrophoresis

A simple, rapid and validated capillary electrophoretic method has been developed for the separation and determination of ofloxacin and ornidazole in pharmaceutical formulations with detection at 230 nm. Optimal conditions for the quantitative separations were investigated. Analysis times shorter than 4 min were obtained using a background electrolyte solution consisting of 25 mmol/L phosphoric acid adjusted with 1 m Tris buffer to pH 8.5, with hydrodynamic injection of 5 s and 20 kV separation voltage. The validation criteria for accuracy, precision, linearity and limits of detection and quantitation were examined and discussed. An excellent linearity was obtained in concentration range 25–250 µg/mL. The detection limits for ofloxacin and ornidazole were 1.03 ± 0.11 and 1.80 ± 0.06 µg/mL, respectively. The proposed method has been applied for the analysis of ofloxacin and ornidazole both individually and in a combined dosage tablet formulation. The proposed validated method showed recoveries between 96.16 and 105.23% of the nominal contents. Copyright © 2009 John Wiley & Sons, Ltd.     

Eco‐friendly ionic liquid assisted capillary electrophoresis and α‐acid glycoprotein‐assisted liquid chromatography for simultaneous determination of anticancer drugs in human fluids

In the current work, two eco‐friendly analytical methods based on capillary electrophoresis (CE) and reversed phase liquid chromatography (RPLC) were developed for simultaneous determination of the most commonly used anticancer drugs for Hodgkin's disease: methotrexate (MTX), vinblastine, chlorambucil and dacarbazine. A background electrolyte (BGE) of 12.5 mmol/L phosphate buffer at pH 7.4 and 0.1 µmol/L 1‐butyl‐3‐methyl imidazolium bromide (BMImBr) ionic liquid (IL) was used for CE measurements at 250 nm detection wavelength, 20 kV applied voltage and 25 °C. The rinsing protocol was significantly improved to reduce the adsorption of IL on the interior surface of capillary. Moreover, RPLC method was developed on α‐1‐acid glycoprotein (AGP) column. Mobile phase was 10 mmol/L phosphate buffer at pH 6.0 (100% v/v) and flow rate at 0.1 mL/min. As AGP is a chiral column, it was successfully separated l ‐MTX from its enantiomer impurity d ‐MTX. Good linearity of quantitative analysis was achieved with coefficients of determinations (r²) >0.995. The stability of drugs measurements was investigated with adequate recoveries up to 24 h storage time under ambient temperature. The limits of detection were <50 and 90 ng/mL by CE and RPLC, respectively. The using of short‐chain IL as an additive in BGE achieved 600‐fold sensitivity enhancement compared with conventional Capillary Zone Electrophoresis (CZE). Therefore, for the first time, the proposed methods were successfully applied to determine simultaneously the analytes in human plasma and urine samples at clinically relevant concentrations with fast and simple pretreatments. Developed IL‐assisted CE and RPLC methods were also applied to measure MTX levels in patients’ samples over time. Copyright © 2014 John Wiley & Sons, Ltd.     

Determination of Manganese(II) with Preconcentration on Almond Skin and Determination by Flame Atomic Absorption Spectrometry

Almond skin was used as a biosorbent by solid-phase extraction for the preconcentration of manganese(II) before the determination by flame atomic absorption spectrometry. Characterization of almond skin was performed by infrared spectroscopy. The functional groups of the almond skin surface were shown to be beneficial for the adsorption of manganese(II). At pH 6.0, the manganese(II) ions were retained on the almond skin and afterward quantitatively eluted using 1.5?mol?L^?1 nitric acid. The pH, flow rate and volume of sample, concentration, and flow rate of eluent and interfering ions were characterized. Using a sample size of 30?mL, a linear dynamic range of 1–120?µg?L^?1 was obtained. A detection limit of 0.24?µg?L^?1 manganese(II) and a relative standard deviation of 1.6% at 30?µg?L^?1 were achieved. The accuracy of the present procedure was evaluated by the determination of manganese(II) in a certified reference material (GSB07-1189-2000). The protocol was also used for the determination of manganese(II) in wastewater. The fortified recoveries were from 99.0 to 99.4%.     

Multivariate optimization of a capillary zone electrophoresis assay method for simultaneous quantification of metformin and vildagliptin from a formulation

A rapid, accurate, precise, and optimized capillary zone electrophoresis assay was established and validated for the simultaneous quantification of metformin and vildagliptin in tablets. The electrophoretic separation was achieved on an untreated bonded silica capillary with a background electrolyte comprising 25 mM of borate buffer at pH 7.5 at 207 nm. The concentration of the buffer and the pH of BGE were optimized using the multivariate optimization method for determining the retention time and peak area. Furthermore, the sample injection time, capillary oven temperature, and applied voltage were optimized. The capillary zone electrophoresis technique was validated for all required parameters as per the International Conference on Harmonization recommendations. The linearity ranged in the concentrations of 5–500 µg/mL and 5–100 µg/mL with the limit of detections of 0.22 µg/mL and 0.40 µg/mL for metformin and vildagliptin, respectively. In addition, the percent relative standard error for repeatability and inter-day precision was within the acceptable range. The mean recoveries determined by the capillary zone electrophoresis method were 99.2% and 100.4% for metformin and vildagliptin, respectively. Finally, the capillary zone electrophoresis process was effectively used for the assays of metformin and vildagliptin in their solid dosage form, and statistical outcomes were in agreement with the outcomes of the previously validated RP-HPLC method.