HPLC Method For Simultaneous Determination Research Articles

Development and validation of an HPLC method for simultaneous determination of imatinib mesylate and rifampicin

Development and validation of an HPLC method for simultaneous determination of imatinib mesylate and rifampicin

Quality by design approach for green HPLC method development for simultaneous analysis of two thalassemia drugs in biological fluid with pharmacokinetic study.

This work implements a combined experimental approach of analytical quality-by-design (AQbD) and green analytical chemistry (GAC) to develop an HPLC method for simultaneous determination of the two thalassemia drugs, deferasirox (DFX) and deferiprone (DFP), in biological fluid for the first time. This integration was designed to maximize efficiency and minimize environmental impacts, as well as energy and solvent consumption. To accomplish this goal, an analytical quality-by-design approach was performed, beginning with quality risk assessment and scouting analysis, followed by Placket–Burman design screening for five chromatographic parameters. Critical method parameters were thoroughly recognized and then optimized by using a two levels-three factors custom experimental design to evaluate the optimum conditions that achieved the highest resolution with acceptable peak symmetry within the shortest run time. The desirability function was used to define the optimal chromatographic conditions, and the optimal separation was achieved using an XBridge® HPLC RP-C18 (4.6 × 250 mm, 5 μm) column with ethanol : acidic water at pH 3.0 adjusted by phosphoric acid in the ratio of (70 : 30, v/v) as the mobile phase at a flow rate of 1 mL min−1 with UV detection at 225 nm at a temperature of 25 °C. Linearity was obtained over the concentration range of 0.30–20.00 μg mL−1 and 0.20–20.00 μg mL−1 for DFX and DFP, respectively, using 20.00 μg mL−1 ibuprofen (IBF) as an internal standard. The established method's greenness profile was evaluated and measured using various assessment tools, and the developed method was green. For the validation of the developed method, FDA recommendations were followed, and all the results obtained met the acceptance criteria. The suggested method was successfully used to study the pharmacokinetic parameters of DFX and DFP in rat plasma. Due to the substantial increase in bioavailability of the two iron chelating drugs, the results from this study strongly recommend their co-administration.

Determination of Five Carotenoids in Eggs and Chicken by HPLC

A HPLC method for simultaneous determination of astaxanthin, lutein, cantharidin, zeaxanthin and β-carotene in eggs and chicken was developed. The results showed a good linear relationship in the range of 0.5~100 μg/mL for five carotenes, and the coefficients of determination were all above 0.996. The limits of detection of the method were between 0.10 and 0.20 mg/kg, with the limits of quantitation were between 0.33 and 0.66 mg/kg. At the spiked levels of 1, 10 and 20 mg/kg, the recoveries of eggs and chicken samples were 71.6%~112.9% and 88.6%~119.7%, respectively, with RSD≤7.2%. The method is rapid, simple, accurate and reproducible. It is suitable for the detection of five kinds of carotenoids in complex matrix samples such as eggs and chicken. It is of great significance for the market supervision of eggs and chicken.

Robust optimization of gradient RP HPLC method for simultaneous determination of ivabradine and its eleven related substances by AQbD approach

Abstract This paper is aimed at developing a gradient elution reversed-phase high-performance liquid chromatography (RP-HPLC) method for the separation of a complex mixture composed of ivabradine and its eleven impurities, in a reasonable timeframe. In order to obtain a robust and reliable HPLC method for separation of this mixture, Analytical Quality by Design (AQbD) was applied. This approach demonstrated to be useful in development of a long lasting life cycle methods. Four chromatographic variables were defined as key method parameters (KMPs) and optimized towards the analytical target profile (ATP). Designated KMPs were initial and final amount of acetonitrile in the mobile phase, pH value of the aqueous phase and gradient time, while resolutions of critical peak pairs were denoted as critical method attributes (CMAs). Relationships between KMPs and CMAs were obtained with the aid of Design of Experiments (DoEs) methodology among which Box-Behnken design (BBD) was employed to gain valid mathematical models. Obtained mathematical equations were used to construct the Design Space (DS) and select reliable optimal separation conditions. They included 11% (v/v) and 34% (v/v) of initial and final amount of acetonitrile, respectively, as well as 45 min of gradient elution time and 20 mM ammonium acetate as aqueous mobile phase with pH set to 7.35. The possibility to separate the diastereoisomers of impurity X was also evaluated. It was demonstrated that this separation could not be achieved in gradient elution mode within the defined variable domains and in a reasonable time span. The developed method was validated according to ICH Q2 (R1) guideline and met all the required criteria.

One step assay of the four plant ingredients in Yangxue Anshen syrup by HPLC method

Objective To establish a HPLC method for simultaneous determination of quercitrin, luteoloside, rutin and 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside in Yangxue Anshen syrup. Methods Waters symmetry C18 column (250 mm×4.6 mm, 5 μm) was used with 0.1% acetic acid (A) and methanol (B) as the mobile phase. Gradient elution was performed at a flow rate of 1.0 ml/min, 0-15 min, 95%-90%A; 15-35 min, 90%-70%A; 35-55 min, 70%-60%A; 55-85 min, 60%-50%A; 85-95 min, 10%A. The detection wavelengths were 256 nm and 320 nm. Column temperature was 30 ℃ and the injection volume was 10 μl. Results Quercitrin, luteoloside, rutin and 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside showed good linear relationship within the range of 10-300, 5.0-150.0, 5.0-150.0, 20.0-600.0 µg/ml(r≥0.9989), respectively. The average recovery was (96.75±1.41)%, (99.61±1.01)%, (97.18±1.96)% and(99.12±0.97)% (n=6), respectively. Conclusion The established method is simple, accurate and stable, which can be used for the simultaneous determination of 4 components in Yangxue Anshen syrup.

A Fast and Validated HPLC Method for Simultaneous Determination of Dopamine, Dobutamine, Phentolamine, Furosemide, and Aminophylline in Infusion Samples and Injection Formulations.

A simple, fast, and validated HPLC method was developed for the simultaneous quantization of five cardiovascular agents: dopamine (DPM), dobutamine (DBM), phentolamine (PTM), furosemide (FSM), and aminophylline (APL) either in infusion samples or in an injection dosage form. The proposed method was achieved with a 150 mm × 4.6 mm, 5.0 μm C18 column, by using a simple linear gradient. Mobile phase A was buffer (50 mM KH2PO4) and mobile Phase B was acetonitrile at a flow rate of 1.0 mL/min. The column temperature was kept at 30°C, and the injection volume was 20 μL. All analytes were separated simultaneously at a retention time (tr) of 3.93, 5.84, 7.06, 8.76, and 9.67 min for DPM, DBM, PTM, FSM, and APL, respectively, with a total run time of less than 15.0 min. The proposed method was validated according to ICH guidelines with respect to accuracy, precision, linearity, limit of detection, limit of quantitation, and robustness. Linearity was obtained over a concentration range of 12.0–240.0, 12.0–240.0, 20.0–200.0, 6.0–240.0, and 10.0–200.0 μg/mL DPM, DBM, PTM, FSM, and APL, respectively. Interday and intraday accuracy and precision data were recorded in the acceptable limits. The new method has successfully been applied for quantification of all five drugs in their injection dosage form, infusion samples, and for evaluation of the stability of investigated drugs in mixtures for endovenous use. The results of the stability study showed that mixtures of DPM, DBM, PTM, FSM, and APL in 5% glucose or 0.9% sodium chloride injection were stable for 48 hours when stored in polypropylene syringes at 25°C.

Development and validation of a fast and simple HPLC method for the simultaneous determination of bisoprolol and enalapril in dosage form

Aim. We aimed to develop and validate fast, simple, accurate, robust and rugged chromatographic method for simultaneous determination of bisoprolol fumarate and enalaril maleate in solid pharmaceutical dosage form, with using chaotropic strong chaotropic perchlorate anions in composition of mobile phase. Materials and methods. Fast simple HPLC method for simultaneous determination of bisoprolol and enalapril in solid pharmaceutical dosage forms was developed, with perfect peak symmetries eluting at 4.7 and 5.2 miutes, with mobile phase composed of methanol and diluted perchloric acid pumped with 1ml/min on Zorbax Rx C8 250x4.6mm, 5um column thermostated at 42 °C, and monitored UV signal at 214nm. Mobile phase was composed of 55%methanol and 45% perchloric acid (0.07%v/v). Results. Usage of presence of perchloric anions showed very useful role in peak shape and chromatogram view, due to distinguished chaotropic characteristics of perchlorate anions on molecules containing nitrogen atoms in molecular structures of analytes, in acidic pH environment. Linearity was examined and proven at different concentration levels in the range of working concentration of bisoprolol (20–200 ug/ml) and enalapril (20–200 ug/ml). The methods achieved very good validation parameters, with determined LOQ about 0.032 mg/ml and LOD about 0.003 mg/ml for bisoprolol, and LOQ about 0.045 mg/ml and LOD 0.005 mg/ml for enalapril. The high value of recoveries obtained for bisoprolol and enalapril indicates that the proposed method was found to be accurate. Conclusion. A new fast and simple, but selective, accurate, precise and robust HPLC method for simultaneous determination of bisoprolol and enalapril in tablets was developed and many possible variations of the same were suggested. The developed method for the simultaneous quantification of bisoprolol and enalapril from solid dosage formulations offers simplicity essential for quality control of a large number of samples in short time intervals, which is necessary for routine analysis.

Simultaneous HPLC-DAD determination of seven intense sweeteners in foodstuffs and pharmaceuticals using a core-shell particle column

As diabetes and obesity have become an epidemic across the world, sweetener compounds are commonly used due to medical need and aesthetic worries. Because of legal limitations and synergistic effects, sweeteners are used together; as a result, their simultaneous determination has become a current topic. A novel HPLC method for simultaneous determination of acesulfame-K, saccharin, aspartame, alitame, neohesperidin dihydrochalcone, rebaudioside-A and neotame in various matrices was described. The proposed method was applied using a core-shell (superficially porous) silica particle column as a stationary phase, and a mobile phase consisting of acetonitrile, phosphate buffer and water. The method provided limits of detection in the range of 0.03–1.12 mg L−1, with recoveries between 95.69–103.99 % and precision better than 1.90 %. The developed method was successfully applied to 65 different commercial foodstuffs and pharmaceutical products by using easy to perform sample preparation applications, including steps such as simple dissolution, dilution and filtration. It was found that none of the analyzed food samples was above the legally imposed limits and contained no alitame, that was not allowed to be used. It was also observed that the results were in accordance with the product label information and did not exceed the limit values for foods.

Synthesis and analysis of 4-(3-fluoropropyl)-glutamic acid stereoisomers to determine the stereochemical purity of (4S)-4-(3-[18F]fluoropropyl)-L-glutamic acid ([18F]FSPG) for clinical use.

(4S)-4-(3-[18F]Fluoropropyl)-L-glutamic acid ([18F]FSPG) is a positron emission tomography (PET) imaging agent for measuring the system xC- transporter activity. It has been used for the detection of various cancers and metastasis in clinical trials. [18F]FSPG is also a promising diagnostic tool for evaluation of multiple sclerosis, drug resistance in chemotherapy, inflammatory brain diseases, and infectious lesions. Due to the very short half-life (110 min) of 18F nuclide, [18F]FSPG needs to be produced on a daily basis; therefore, fast and efficient synthesis and analytical methods for quality control must be established to assure the quality and safety of [18F]FSPG for clinical use. To manufacture cGMP-compliant [18F]FSPG, all four nonradioactive stereoisomers of FSPG were prepared as reference standards for analysis. (2S,4S)-1 and (2R,4R)-1 were synthesized starting from protected L- and D-glutamate derivatives in three steps, whereas (2S,4R)-1 and (2R,4S)-1 were prepared in three steps from protected (S)- and (R)-pyroglutamates. A chiral HPLC method for simultaneous determination of four FSPG stereoisomers was developed by using a 3-cm Chirex 3126 column and a MeCN/CuSO4(aq) mobile phase. In this method, (2R,4S)-1, (2S,4S)-1, (2R,4R)-1, and (2S,4R)-1 were eluted in sequence with sufficient resolution in less than 25 min without derivatization. Scale-up synthesis of intermediates for the production of [18F]FSPG in high optical purity was achieved via stereo-selective synthesis or resolution by recrystallization. The enantiomeric excess of intermediates was determined by HPLC using a Chiralcel OD column and monitored at 220 nm. The nonradioactive precursor with >98% ee can be readily distributed to other facilities for the production of [18F]FSPG. Based on the above accomplishments, cGMP-compliant [18F]FSPG met the acceptance criteria in specifications and was successfully manufactured for human use. It has been routinely prepared and used in several pancreatic ductal adenocarcinoma metastasis-related clinical trials.

Direct Injection Microemulsion HPLC Method for Simultaneous Determination of Morphine, Tramadol and Lornoxicam in Biological Fluids Using Monolithic Column

<P>Objective: A rapid and environmental friendly microemulsion liquid chromatographic method was developed for simultaneous quantification of morphine (MOR), tramadol (TRA) and lornoxicam (LOR) in biological fluids. </P><P> Methods: Microemulsion used in this study was an aqueous solution containing sodium dodecyl sulfate (0.12 M), n-propanol (10%), ethyl acetate (0.75%), tri-ethyl amine (0.3%), orthophosphoric acid (0.15 %) and the pH was adjusted to 3.0 with orthophosphoric acid. Chromatographic separation was carried out on a monolithic C18 column and a mobile phase flow rate of 1.0 mL min−1 was applied throughout the analysis. The data was monitored using UV-detection mode at a wavelength of 220 nm. </P><P> Results: Under the optimized conditions, all the studied drugs were well resolved and completely eluted within 6 min. The proposed method was linear over the concentration ranges of 0.5−100, 0.75−125 and 0.25−50 μg mL−1; limits of detection of 0.074, 0.086 and 0.056 μgmL−1 and limits of quantification of 0.21, 0.28 and 0.12 were recorded for TRA, LOR, and MOR, respectively. The developed method was fully validated according to the ICH guidelines. The method was successfully utilized to estimate the tested analytes in plasma and urine samples, which were directly injected into the chromatographic system after suitable dilution with the microemulsion. </P><P> Conclusion: The developed method is considered to be very efficient to analyze the cited drugs in different biological fluids with low running costs and short analysis time.</P>

A Novel HPLC Method for Simultaneous Determination of Methyl, Ethyl, n-propyl, Isopropyl, n-butyl, Isobutyl and Benzyl Paraben in Pharmaceuticals and Cosmetics.

The alkyl esters of p-hydroxybenzoic acid at the C-4 position, "the parabens," including methyl, ethyl, propyl, and butyl, are widely used as antimicrobial preservatives in foods, cosmetics, and pharmaceuticals. Official regulations on the use of these compounds make their analysis essential for the estimation of their exposure. On this basis, the presented study was realized to develop a simple, selective and cheap high-performance liquid chromatographic method for the quantitative determination of methylparaben, ethylparaben (EP), n-propyl paraben (NPP), isopropyl paraben (IPP), n-butyl paraben (NBP), isobutyl paraben (IBP) and benzyl paraben (BP) in pharmaceuticals and cosmetic products. The chromatographic separation of the analytes was achieved under flow rate gradient elution conditions using a C18-bonded core-shell silica particle column (2.6 μm particle size, 150 × 3.0 mm from Phenomenex Co.). The samples were injected into the system as aliquots of 1.0 μL, and the compounds were detected by using a photodiode array detector set at 254 nm wavelength. With this technique, seven paraben derivatives can be determined in the concentration range of 250-2000 ng/mL. The recovery of the method is in the range of 99.95-13.84%, and the RSD is at a maximum value of 3.95%. The proposed method was fully validated and successfully applied to different pharmaceutical and cosmetic samples (n=16), including syrups, suspensions, oral sprays, gels, etc. At least one paraben derivative was detected in six samples and was determined quantitatively. The maximum amount of a paraben derivative found in the analyzed samples was 321.7 ng/mL, which was MP. To the best of our knowledge, this is the first LC method, which is applicable both on pharmaceutical and cosmetic samples.

Box-Behnken Design-Desirability Function Approach in Optimization of HPLC Method for Simultaneous Determination of Ibuprofen Along with Additives in Syrup Formulation.

The advantages of simultaneous analyses are a decrease in analysis time and a more economical use of solvents and reagents. It is desirable that HPLC analyses possess both short term and good resolution. The aim of the current study is to develop an HPLC method for the simultaneous determination of ibuprofen, sodium benzoate, methyl paraben and propyl paraben as preservatives, and sunset yellow as a colorant, in syrup formulation. To optimize chromatographic separation conditions, multi-response optimization using the Derringer's desirability function was employed for the development of a rapid and efficient HPLC method. The ranges of independent variables used for the optimization process were 50-60% (v/v) for acetonitrile, 5.0-7.0 for pH, and 1.0-2.0 mL/min for flow rate of the mobile phase. The effects of these variables on the output responses, such as critical resolution between sunset yellow and sodium benzoate and retention time of the last peak indicating analysis time of the method, were evaluated by statistical experimental design. Optimum conditions fixed for the simultaneous analyses were acetonitrile:phosphate buffer (60:40, v/v), pH 5.0, and a flow rate of 1.8 mL/min. The eluate was monitored using a photo diode detector set at 220 nm. Total chromatographic analysis time was approximately 3 min. The developed method validated as per International Conference on Harmonization guidelines was successfully applied for the determination of five compounds in their pharmaceutical formulation. This efficient method has isocratic elution system and can be used for routine analyses of these compounds in similar pharmaceutical products.

Innovative Quality by Design Approach for Development of Green Micellar HPLC Method for Simultaneous Determination of Atorvastatin and Amlodipine

The combined implementation of quality by design principles and green analytical chemistry leads to development of green micellar HPLC method for analysis of atorvastatin calcium and amlodipine besylate in binary mixtures and in their tablet dosage forms within 8 min. A two-level fractional factorial design was implemented for screening of different method parameters affecting chromatographic responses. Box–Behnken design was then used to study and optimize the most critical parameters. The optimum chromatographic conditions obtained from Box–Behnken design involved the use of a mixture of 0.17 M sodium dodecyl sulfate solution adjusted to pH 2.9 and 10%v/v n-butanol as mobile phase at a flow rate of 1.5 mL min−1 and column temperature kept at 45 oC. The stationary phase was X-Bridge™ (150 mm × 4.6 mm, 5 μm) column. The fluorescence detection was programmed at 276/378 nm (excitation/ emission) for the first 5 mins for atorvastatin then switched to 366/442 nm (excitation/emission) for amlodipine. A linear response was obtained over the ranges of 0.2–25 μg mL−1 for both drugs. The proposed method was validated and successfully implemented for the simultaneous determination of cited drugs in their different tablet dosage forms. The method was additionally applied to content uniformity testing according to the official guidelines. The application of quality by design principles and green analytical chemistry results in development of robust green method with less trial and error experiments.

Studies on the component analysis and quality control in tonic wine preparation of King-Mon-Long-Fong-Jyo

An HPLC method for simultaneous determination of seven marker substances was established for the quality control in tonic wine preparation of "King-Mon-Long-Fong-Jyo". These marker substances were gomisin A and schizandrin from Schizandrae Fructus, loganin from Corni Fructus, cinnamic acid and cinnamaldehyde from Cinnamomi Cortex, scopoletin and ferulic acid from Angelicae Radix. Different rice wine extraction volume and extraction temperature conditions were performed to evaluate quality of King-Mon-Long-Fong-Jyo. Extracted samples were run through the HPLC column (Inertsil 5 ODS-2, 4.6 I.D. × 250 mm.) at 30°C and the column was developed with a mixture of 20% acetonitrile and 70% acetonitrile (adjusted to pH 3.0 with phosphoric acid) aqueous solution and then employed linear gradient elution method at a flow-rate of 1.0 mL/min. An UV 250 nm was used for the detection of the marker substances. Relative standard deviations of intra- and inter-day analysis were less than 5%. This separation method could be successfully applied for the simultaneous determination of seven marker substances in "King-Mon-Long-Fong-Jyo".

Analysis of insecticide clothianidin and its metabolites in rice by liquid chromatography with a UV detector

An HPLC method for simultaneous determination of insecticide clothianidin and its metabolites (TZNG, TMG, TZMU, and MNG) in rice was developed and is described in this paper. We extracted the parent clothianidin compound and its metabolites from samples with methanol and an aliquot of the extract was evaporated in a rotary evaporator to remove methanol. The residue was dissolved in 1 mL of 0.005 M 1-sodium octansulfonate (pH 8.3) and transferred to the ENVI-CARB cartridge coupled with an HLB cartridge for solid phase extraction (SPE). Clothianidin and its 4 metabolites were eluted from the cartridges with 3.5 mL of 70% acetonitrile in 0.005 M 1-sodium octansulfonate (pH 7). Determination and separation of clothianidin and its four metabolites were performed in an Agilent Aq column using gradient mobile phase and different UV wavelengths. The average recoveries of clothianidin, TZNG, TMG, TZMU, and MNG were 110%, 87%, 113%, 108%, and 61%, respectively, spiked at 2 ppm into rice. The relative standard deviation (RSD) was determined to be less than 10% in a triple-repeated confirmation test. The limits of quantification (LOQ) were 0.05 ppm for clothianidin, TZNG, TZMU and MNG, and 0.1 ppm for TMG in rice. The method was applied for the determination of clothianidin and its metabolites in 8 polished and 4 unpolished rice grain samples, each of which was collected from a different market in Taiwan. No residue of clothianidin or any of its metabolites was found at levels or at greater than the LOQ in these rice samples.

A Rapid and Sensitive HPLC Method for Simultaneous Determination of Irinotecan Hydrochloride and Curcumin in Co-delivered Polymeric Nanoparticles.

In recent years, a great deal of attention has been paid to the combined use of multiple antitumor drugs for better cancer treatment. The aims of the study are to construct a nanoparticle drug delivery system for the co-delivery of irinotecan hydrochloride and curcumin and to develop an analytical method for simultaneously quantifying these molecules, which is essential for further studies of the co-delivered nano system. The irinotecan hydrochloride and curcumin co-delivered nanoparticle (ICN) were prepared by combinatorially entrapping them into polyethylene glycol-poly lactic acid-co-glycolic acid (PEG-PLGA) polymeric nanoparticles. A simple, sensitive and rapid high-performance liquid chromatography method was developed and validated to simultaneously quantify the compounds in the co-delivered nanoparticle system. Acetonitrile and ultrapure water containing sodium dodecyl sulfate (0.08mol/L), disodium phosphate (Na2HPO4, 0.002mol/L) and acetic acid (4%, v/v) were used as the mobile phase and their ratio was set at 50:50. The flow rate was set to 1.0mL/min, and the temperature in the column oven was maintained at 40°C. The analysis was carried out at 256 and 424nm to assess irinotecan hydrochloride and curcumin, respectively. Detectors with only one channel can also visualize both analytes in one chromatogram at 379nm and still demonstrate acceptable sensitivity. The retention times for irinotecan hydrochloride and curium were 3.317 and 5.560min, respectively. The method developed was confirmed to be sensitive, accurate (recovery, 100±2%), precise (relative standard deviation, RSD≤1%), robust and linear (R2≥0.9996) in the range from 2.05 to 1050μg/mL. The presented method has been used to quantify irinotecan hydrochloride and curcumin in the co-delivered ICN nano system to assess the drug delivery quality of the nanoparticles and can also be used for routine analysis because of its simplicity and accuracy.

HPLC method for simultaneous determination of impurities and degradation products in Cardiazol

Aim. The aim of study was to develop a simple and accurate procedure that could be applied for the determination of impurities and degradation products in cardiazol. Materials and methods. Separation in samples was carried out with Acquity H-class UPLC system (Waters, Milford, USA) equipped with Acquity UPLC BEH C18 column (2.1 × 50 mm, 1.7 μm) (Waters, Milford, USA). Xevo TQD triple quadrupole mass spectrometer detector (Waters Millford, USA) was used to obtain MS/MS data. Mobile phase A: 0.1% solution of trifluoroacetic acid R in water R; Mobile phase B: acetonitrile R. Samples were chromatographed in gradient mode (Table 1). Flow rate of the mobile phase: 1 ml / min. Column temperature: 30 °С. Detection: at 240 nm wavelength. Injection volume: 10 μl. Results. The retention time of the main substance is about 18.5 minutes. The order of the peak, the retention times and relative retention times: impurity B (12.04, 0.65); impurity А (18.5; 0.98); Cardiazol (18.87; 1.00). The LOD and LOQ values obtained were in the range of 30 ng/mL to 100 ng/mL and 80 ng/mL to 310 ng/mL respectively (with respect to sample concentration of 2 mg/ml). Linearity was established in the range of LOQ level to 0.2% having regression coefficients in the range of 0.9996 to 0.9999. The change in the temperature of the column affects the degree of separation of cardiazol and the impurity A, and thus, with a decrease of 5 ° C, the degree of separation is (1.06), while with increasing this index (3.43). When changing the flow rate of the mobile phase, the degree of separation changes in the following order, with a decrease to 0.9 ml / min separation (1.90), with an increase in speed to 1.1 ml / min (2.45). When the number of mobile phase B decreases by 5%, the degree of separation varies by (2.65), with an increase of 5% (1.82). In comparison with the chromatogram of the tested solution, the substance is not resistant to the action of peroxide, alkaline and acid decomposition. Conclusion. 1) HPLC method was developed and validated for the simultaneous detection and quantitation of impurities formed during the synthesis of cardiazol. 2) The method proved to be sensitive, selective, precise, linear, accurate and stability-indicating.

Isocratic HPLC Method for Simultaneous Determination of Amlodipine and Xipamide in Human Plasma

An HPLC method had been developed and validated for rapid simultaneous separation and determination of the two antihypertensive drugs, amlodipine and xipamide in human plasma within 5 minutes.

Development and application of a rapid HPLC method for simultaneous determination of hyperoside, isoquercitrin and eleutheroside E in Apocynum venetum L. and Eleutherococcus senticosus

Apocynum venetum L. and Eleutherococcus senticosus have been used for hundreds of years to treat hypertension in China. In previous research, there was not a suitable quality control of method for the formulas of Apocynum venetum L. and Eleutherococcus senticosus. It is urgent and essential to develop modern analytical methods for Apocynum venetum L. and Eleutherococcus senticosus to ensure the quality of the formulas. A rapid approach for simultaneous determination of hyperoside, isoquercitrin and eleutheroside E in Apocynum venetum L. and Eleutherococcus senticosus by high-performance liquid chromatography with a diode array detector was described and validated. The full method validation, including the linearity, limits of detection and quantification, precision, repeatability, stability and recovery, was examined. All target components, including isomers of hyperoside and isoquercitrin, were baseline separated in 35 min. The developed method was sensitive, reliable and feasible. With this method, the optimal decoction conditions of Apocynum venetum L. and Eleutherococcus senticosus were selected, and their quality analysis was carried out. Furthermore, an herbal compatibility study of Apocynum venetum L. and Eleutherococcus senticosus based on detecting variations in the content of their active ingredients was performed by the developed HPLC method. It could be an alternative for the quantitative analysis of herbs that contain hyperoside, isoquercitrin or (and) eleutheroside E in the future.

Simplified HPLC method for simultaneous determination of erythromycin and tretinoin in topical gel form

AbstractA simple, rapid and validated high‐performance liquid chromatographic method has been developed for the simultaneous determination of tretinoin and erythromycin in bulk and topical gel form. The analysis was achieved under isocratic mode with a specific reversed stationary phase and, using an eluent composed of acetonitrile/2‐methyl‐2‐propanol/hydrogen phosphate buffer of pH 7.0, delivered at a flow‐rate of 1.0 mL min−1, with UV detection at 215 nm. The procedure was validated for specificity, linearity, precision, accuracy and robustness. The calibration plots were linear over the concentration ranges of: 0.002–4.8 and 0.025–30 μg mL−1, with lower detection limits of 0.007 and 0.0008 μg mL−1 for erythromycin and tretinoin, respectively. The developed method was applied for the simultaneous quantitative determination of both drugs in their marketed alcoholic gel formulation. Results of the mean percentage recoveries were in the range of 99.5‐100.8%.