Determination Of Valsartan Research Articles

Synthesis of molecularly imprinted polymer as a nanosorbent for dispersive magnetic micro solid-phase extraction and determination of valsartan in biological samples by UV–Vis Spectrophotometry: Isotherm, kinetics, and thermodynamic studies

A magnetic molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization utilizing Fe3O4@SiO2-MPS as a magnetic core, itaconic acid as a functional monomer, azobisisobutyronitrile as an initiator, and ethylene glycol dimethacrylate as a cross linker. It was then applied as a nanosorbent for dispersive magnetic micro solid phase extraction (DM-µ-SPE) and determination of valsartan in biological fluids. The morphology and structure of magnetic MIP were characterized by Fourier-transform infrared spectroscopy, Field Emission Scanning electron microscopy, Vibrating sample magnetometer, Energy dispersive x-ray analysis, and Thermogravimetric analysis. The influence of operation conditions on sorption, such as pH (4–10), contact time (10–25 min), initial concentration (1–30 mg L−1), and temperature (25–40 °C) was investigated. After the extraction step, the valsartan concentration was determined by UV–Vis spectrophotometer at 253 nm. The isotherm and kinetic of valsartan sorption were best fitted by the Langmuir model (R2 = 0.987) and the Pseudo second-order kinetic model (R2 = 0.971), respectively. The maximum monolayer sorption capacity for magnetic MIP was obtained to be 4.56 mg g−1. The analytical approach demonstrated favorable figures of merit, with a linear dynamic range of 10–100 µg L−1, a low detection limit of 0.56 µg L−1, and an acceptable preconcentration factor of 5 acquired in optimum conditions. The recoveries of the suggested technique at three spiked levels of analysis were in the range of 101 %–102 %. Valsartan was extracted from various real samples (urine and human blood plasma samples) utilizing the proposed magnetic nanosorbent, and the results exhibited that magnetic MIP was favorable for extraction and measurement of trace amounts of valsartan in biological samples.

Determination of valsartan in its pharmaceutical preparations using high-performance liquid chromatography technique

High-performance liquid chromatography technique was used to estimate valsartan in its pure form and in some pharmaceutical preparations. It was found through the results obtained that the proposed method is sensitive and accurate, and the estimation was done in a short time. In this work, a No L1, 150mm separation column was used to separate the components as they were type The UV spectrometer was used as a wavelength of 239 nm, the column temperature was 40°C, and the mobile phase consisted of 50:50 (acetonitrile: methanol: drops of triethylamine, pH = 2.4) at a flow rate of 1 ml/min. Through what was reached, we find that the method is sensitive, accurate and compatible, as the percentage recovery reached (100.63-103.35), and the linearity was (40-120 mcg/ml) for valsartan. The method was applied to a number of pharmaceutical preparations available in the local market, and the method was successful in the quantitative estimation of valsartan.

Green preparation of dual-template chitosan-based magnetic water-compatible molecularly imprinted biopolymer

In the current study, a green method was used for the fabrication of dual-template chitosan-based magnetic water-compatible molecularly imprinted biopolymer in water without using organic and toxic reagents and then, its application as a sorbent for the simultaneous pre-concentration and determination of valsartan (VAL) and losartan (LOS) from urine samples followed by HPLC-UV.Chitosan was used as a multi-functional monomer due to its unique properties in terms of non-toxic, cost-effectiveness, readily available, biocompatible, biodegradable and easy to polymerize in mild condition. The proposed sorbent represents the exceptional properties in terms of green synthesis, high magnetic strength, bio-compatibility, high selectivity, fast equilibrium adsorption as well as high adsorption capacity. In the optimized conditions, the developed MMIP-DMSPE-HPLC/UV method showed a wide linear range of 5.0 − 1500.0 μg L−1 for VAL and 8.0 − 1500 μg L−1 for LOS and low LODs of 1.4 and 2.3 μg L−1 for VAL and LOS, respectively with RSD% values less than 5.0, (n = 5). The obtained recoveries were 95.6–100.2 % for VAL and 92.0–98.1 % for LOS which showed the applicability of green, water-compatible and bio-compatibility of the proposed method for neat and selective extraction of VAL and LOS from complicated urine samples.

Magnetic iron oxide nanoparticles for HPLC determination of valsartan in aqueous environmental samples, biological samples and tablet dosage forms

ABSTRACT Magnetic iron oxide nanoparticles (MIONPs) were newly synthesised and then modified by cetyltrimethylammonium bromide (CTAB) for solid phase extraction, preconcentration and determination of valsartan (VAL) followed by high performance liquid chromatographic analysis. The synthesised magnetic Fe3O4 nanoparticles were used as adsorbent and methanol was used as desorbing solvent. The separation was performed using a RP-C18 BDS hypersil chromatographic column and an isocratic mobile phase consisting of phosphate buffer (0.03 M):acetonitrile:methanol (40:40:20%). A diode array detector at wave length 210 nm was used. Chromatographic analysis time was less than 5 minutes per sample with complete resolution of VAL from the different studied matrices components (tR of VAL = 4.20 minutes). Important parameters such as adsorbent and CTAB volume, extraction time and desorption solvent type and time were optimised. A good linear response was obtained in the concentration range of 10–150 ng/mL with determination coefficient (r 2) of 0.9998. Limits of detection and quantification were found to be 2.02 and 6.72 ng/mL. The proposed method was applied successfully for determination of VAL in raw material, aqueous environmental samples, biological samples, tablet dosage forms with good recovery values indicating high accuracy of the method.

Voltammetric study of valsartan–Ni complex: application to valsartan analysis in pharmaceuticals and in vivo human urine profiling

Valsartan (VAL) can be analyzed at the mercury electrode in the presence of nickel (II) yielding a sensitive cathodic peak at − 0.7 V which may be attributed to the reduction of the complex formed between nickel and VAL. Low LOD and LOQ were achieved (7.6 and 23 nM, respectively) permitting the analysis of VAL not only in its pharmaceutical formula, but also in human urine. The influence of adding transition metal, Ni(II), to the electrolyte containing VAL, on the voltammetric response was studied. Differential-pulse voltammetry, using working electrode: hanging mercury drop electrode (HMDE), was applied to elucidate and confirm the possible complexation reaction that could occur between VAL and nickel which aids in the determination of VAL in tablets and human urine. A simple cleanup procedure was applied for urine samples that involves the use of solid-phase extraction with the elution of VAL with methanol. The polarographic peak, which corresponds to the reduction of Ni(II) in the formed complex with VAL, was a function of the concentration of VAL, pH of the medium and Ni(II) concentration at the electrode surface. At Britton–Robinson buffer pH 6 and using 800 µM Ni(II), the reduction peak current linearly varied with the VAL concentration over the ranges of 25–150 and 25–200 nM in tablets as well as urinalysis, respectively.

Simultaneous determination of valsartan, amlodipine besylate and hydrochlorothiazide in tablets by near infrared

Interval partial least-squares calibration (iPLS) and synergical partial least-squares calibration (siPLS) methods in combination with near infrared spectroscopy coupled with integrating sphere (NIRA) have been developed for simultaneous determination of amlodipine (AML), valsartan (VAL) and hydrochlorothiazide (HCT) in raw material powder mixtures used for production commercial pharmaceutical product (tablets). Variable selection methods (iPLS and siPLS) were applied to select a spectral range that provided the lowest prediction error in comparison to the full-spectrum model. Spectral data were recorded between 10000 and 4000 cm-1 by NIRA and subdivided into 32 intervals. A relative standard error of prediction (RSEP) of 1.27% for VAL, 1.92% for HCT and 5.19% for AML was obtained after selection of better intervals by siPLS. Results shown that multivariate regression model associated to NIRA is a relatively simple, free-solvent and non-destructive procedure that could be applied to the simultaneous determination of AML, VAL and HCT in routine quality control of pharmaceuticals.

Development of an analytical method for the determination of valsartan in commercial drug and sewage sludge samples by HPLC and evaluation of its stability under simulated gastric conditions

ABSTRACTAn analytical method was developed for determination of valsartan in commercial drug and sewage sludge samples by HPLC–UV using a single wavelength (250 nm). The effect of different environmental storage conditions on the stability of valsartan was examined for a period of 85 days, after which no degradation was observed. The post oral administration stability of the valsartan was also investigated by testing valsartan under simulated gastric conditions. Results obtained showed that the structure of valsartan was conserved over 3.5-h period. The calibration plot of the study was linear over a wide concentration range with a correlation coefficient of 0.9999. The limit of detection and limit of quantitation were found to be 0.014 and 0.046 µ g mL−1, respectively. The percentage recovery of valsartan from sewage sludge was found to be 99.8%.

Densitometry, video-scanning and capillary electrophoresis for determination of valsartan and amlodipine in a combined dosage form: A comparative study

Summary Comparison of classical densitometry, video-scanning, and capillary electrophoresis was performed for determination of angiotensin II receptor antagonist, valsartan, and calcium channels blocker, amlodipine, in a combined dosage form. Thin layer chromatography was performed on RP8F254 TLC plates with a mobile phase consisting of acetonitrile-phosphate buffer at pH 9.0 (5:5, v/v) and temperature 20 °C. Densitometry was done in the reflectance mode at 217 nm for valsartan and in the absorbance mode at 370 nm for amlodipine. Video-scanning was elaborated at 254 and 366 nm for valsartan and amlodipine, respectively. For chromatographic analysis, calibration plots were constructed in the range of 0.4–2.8 μg per spot for valsartan and 0.02–0.14 μg per spot for amlodipine. Capillary electrophoresis (CE) was performed using a 75 μm × 94 cm fused silica capillary (72 cm effective length), 0.01 mol L−1 borate buffer at pH 8.0, 20 kV voltage, 30 °C temperature, hydrodynamic injection (10 mbar, 6 s) and UV de...

UPLC Method for Simultaneous Determination of Valsartan & Hydrochlorothiazide in Drug Products

A new, simple, precise and stability-indicating UPLC (Ultra Performance Liquid Chromatography) method was developed and validated for the simultaneous determination of anti-hypertensive drug Valsartan (VAL) and Hydrochlorothiazide (HCTZ) in combined dosage forms. The method was developed using Kromasil eternity C-18 column (50 mm×2.1 mm, 3.5 μm) with isocratic elution. Triethylamine buffer (0.1% v/v) and methanol (75:25 v/v) were used as mobile phase with 0.6 mL min-1 flow rate at room temperature. The detection wavelength was fixed at 225 nm; the run time was within 2 min. The method was validated in terms of linearity, accuracy and reproducibility. Calibration plots were linear over the range of 7-13 μg/ml for HCTZ and 56-104 μg/ml for VAL. Recovery was in the range of 98-102% with the relative standard deviation of less than 2% for both drugs. The limit of detection and the limit of quantification for the valsartan were found to be 0.8 and 2.4 μg/ml respectively and for hydrochlorothiazide 0.12 and 0.36 μg/ml respectively. The proposed method was also suitable for determination of VAL & HCTZ in bulk and pharmaceutical dosage forms.

STRESS TESTING OF VALSARTAN. DEVELOPMENT AND VALIDATION OF A HIGH PERFORMANCE LIQUID CHROMATOGRAPHY STABILITY-INDICATING ASSAY

Stress testing studies were carried out on Valsartan (VAL) under hydrolytic (acidic, basic, and neutral), photolytic, oxidative, and thermal (in the solid state) conditions. Relevant degradation was observed when the drug was exposed to photolytic conditions, where two degradants (DP-1 and DP-2) were produced and when submitted to acid hydrolysis, which yielded one degradation product (DP-3). A high performance liquid chromatography method for the simultaneous determination of VAL and its degradation products was developed, optimized employing experimental design strategies, and validated, employing fully characterized standards of the degradation products. The results proved the stability-indicating property of the method.

Potentiometric Determination of Amlodipine Besilate and Valsartan Using Microsized and Polymeric Matrix Membrane Sensors

Two poly(vinyl chloride) matrix membrane electrodes responsive to some drugs affecting the cardiovascular system, Amlodipine besilate (AM) and Valsartan (VL), were developed, described and characterized. A microsized graphite selective sensor was investigated with dibutylsebacate (DBS) as a plasticizer in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH) in case of (sensor 1). This sensor 1 was prepared using 2- hydroxy propyl �-cyclodextrin (2HP �-CD) as an ionophore. While sensor 2 preparation was based on precipitation technique with bathophenanthroline iron (II) as electroactive materials in poly(vinyl chloride) (PVC) matrix. Fast and stable Nernstian responses near 1x10 -5 -1x10 -3 M for the two drugs over the pH range 3-6 and 7-9 for the two sensors, respectively, were obtained. The method was successively applied for the determination of AM and VL in presence of each others, in their pharmaceutical formulations and in human plasma samples. The percentages recoveries for the determination of the drugs by the proposed selective electrodes were 99.78 ±0.382 %, 100.23 ± 0.440 %, for sensors 1 and 2, respectively. Statistical comparison between the results obtained by this method and those obtained by the official method and the reported method of the drugs was done and no significant difference was found.

SENSITIVE HPLC METHOD WITH FLUORESCENCE DETECTION AND ON-LINE WAVELENGTH SWITCHING FOR SIMULTANEOUS DETERMINATION OF VALSARTAN AND AMLODIPINE IN HUMAN PLASMA

This study describes the development and validation of a highly sensitive high-performance liquid chromatographic method with fluorescence detection and on-line emission wavelength switching for the simultaneous determination of valsartan (VAL) and amlodipine (AML) in human plasma. Irbesartan (IRB) was used as internal standard (IS). VAL, AML, and IRB were isolated from plasma by nonextractive procedure; simple protein precipitation with methanol. Separations were performed in low pressure gradient mode on Hypersil phenyl 120A analytical column using a mobile phase consisting of phosphate buffer (pH 4.0 ± 0.1):acetonitrile:methanol (60:30:10, v/v/v) at a flow rate of 0.8 mL/min. The detection of VAL and IRB (IS) was carried out at 253 nm (for excitation) and 374 nm (for emission). After elution of VAL and IRB, the detection wavelengths were switched on-line to 393 nm (excitation) and 446 nm (emission) for detection of AML. The linear ranges of the assay were 1–100 and 10–1000 ng/mL for VAL and AML, respectively. The limits of detection (LOD) were 0.3 and 1.6 ng/mL for VAL and AML, respectively. The intra- and inter-assay precisions were satisfactory; the relative standard deviations did not exceed 5.1%. The accuracy of the method was proved; the recovery of VAL and AML from spiked human plasma were 96.6–100.9 and 92.0–104.4% for VAL and AML, respectively. The method had higher throughput as it involved simple sample preparation procedure and short run-time (15 min). The results demonstrated that the proposed method would have great value in pharmacokinetic studies for VAL and AML.

SPECTROPHOTOMETRIC ANALYSIS OF VALSARTAN AND HYDROCHLOROTHIAZIDE

ABSTRACT Two new methods for the simultaneous determination of valsartan and hydrochlorothiazide in pharmaceutical dosage forms have been developed. The first method, based on compensation technique is presented for the derivative spectrophotometric determination of binary mixtures with overlapping spectra. By using ratios of the derivative maxima or the derivative minimum, the exact compensation of either component in the mixture can be achieved, followed by its determination. The second method, differential derivative spectrophotometry, comprised of measurement of the difference absorptivities derivatized in the first order (ΔD 1) of a tablet extract in 0.1 N NaOH relative to that of an equimolar solution in methanol at wavelengths of 227.8 and 276.5 nm, respectively. Neither sample pre-treatment nor separation were required. These methods showed good linearity, precision, and reproducibility. The results obtained were compared with the results of reversed phase HPLC. It was found that the difference was not statistically important between these methods. The proposed methods were accurate, sensitive, precise, reproducible and could be applied directly and easily to the pharmaceutical preparations.

Simultaneous Determination of Valsartan and Hydrochlorothiazide in Tablets by High-Performance Liquid Chromatography

ABSTRACT A method for the simultaneous determination of valsartan and hydrochlorothiazide in tablets is described. The procedure, based on the use of reversed-phase high-performance liquid chromatography, is linear in the concentration range 5.0-10.0 μg ml−1 for valsartan and 0.5-2.0 μg ml−1 for hydrochlorothiazide, is simple and rapid and allows accurate and precise results. The limit of detection was 1.0 μg ml−1 for valsartan and 0.05 μg ml−1 for hydrochlorothiazide.