scholarly journals Extraction and determination of major hypotensive compounds in bark of Eucommia ulmoides Oliv.

2009 ◽  
Vol 61 (4) ◽  
pp. 811-817 ◽  
Author(s):  
Jianbo Xiao ◽  
Xinlin Wei ◽  
Yuanfeng Wang
Keyword(s):  
Quantitative Determination ◽  
Chlorogenic Acid ◽  
Control Method ◽  
Reversed Phase ◽  
Assay Method ◽  
Eucommia Ulmoides ◽  
Extraction Temperature ◽  
Relative Standard ◽  
Geniposidic Acid

A reversed-phase liquid chromatographic method was developed for the quantitative determination of three major hypotensive compounds, namely geniposidic acid, chlorogenic acid, and geniposide in the bark of Eucommia ulmoides. Soxhlet extraction of GPA, GPS, and CA from E. ulmoides was optimized according to the Taguchi experimental design. Maximum global yields were obtained using the following conditions: extraction temperature, 80?C; extraction time, 1 h; number of extractions, three; solvent volume, 16 ml/g of sample; and 50% ethanol concentration in water. Optimal conditions of separation and detection were achieved on a Diamonsil ODS C18 column (150 mm ? 4.6 mm, 5 ?m) with a linear gradient of methanol and 0.04% aqueous phosphoric acid (v/v) at a flow rate of 1.0 ml/min and detection wavelength of 240 nm. All calibration curves showed good linearity (r2 > 0.999) within test ranges. The relative deviation of this method was less than 3% for intra- and inter-day assays, and the recovery percentage of the method was 95-104%, with a relative standard deviation (R.S.D.) of less than 5%. The current assay method was used for quantitative determination of geniposidic acid, chlorogenic acid, and geniposide in five samples of E. ulmoides with different age. The results indicate that the developed method could be readily utilized as a quality control method in working with E. ulmoides.

Optimization of an Aqueous Two-Phase System for the Determination of Trace Ethyl Carbamate in Red Wine

2019 ◽  
Vol 82 (8) ◽  
pp. 1377-1383 ◽  
Author(s):  
LIJUAN MA ◽  
WENZHE TONG ◽  
LIPING DU ◽  
SHIYONG HUANG ◽  
JINYAN WEI ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Red Wine ◽  
Ethyl Carbamate ◽  
Phase System ◽  
Extraction Temperature ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Relative Standard ◽  
Standard Deviations

ABSTRACT In this study, a novel method using gas chromatography–mass spectrometry coupled with ethanol and K2HPO4 aqueous two-phase system (ATPS) was established for the quantitative determination of trace ethyl carbamate (EC) in red wine. The parameters that influence EC extraction in an aqueous two-phase system, including extraction temperature, time, pH, and ethanol concentration, were optimized. Method validation results indicated that the regression coefficient of the proposed method was 0.9979 in the linear range of 10 to 100 μg/L, and the limits of detection and quantification were 2.8 and 9.2 μg/L, respectively. Four red wine samples made from different grape varieties were processed by the proposed method for the repeatability verification, and EC concentrations were between 15.8 and 37.3 μg/L, with the relative standard deviations ranging from 3.5 to 6.6%. Results of the precision assay showed the average recovery of EC in red wine at 95.4 to 107.1%, with the relative standard deviations ranging from 1.4 to 6.2%. This method proved to be simple and reliable for quantitative determination of trace EC in red wine and would give guidance for quality monitoring of various red wines in the production process.

scholarly journals Alternative Liquid Chromatographic Method for Determination of the Methoxyl and 2-Hydroxypropoxyl Content in Cellulose Ether Derivatives

2003 ◽  
Vol 86 (4) ◽  
pp. 694-702
Author(s):  
Joe Rashan ◽  
Raymond Chen ◽  
Todd Zelesky ◽  
Sonja Sekulic
Keyword(s):  
Gradient Elution ◽  
Reversed Phase ◽  
Hydriodic Acid ◽  
Assay Method ◽  
Cellulose Ether ◽  
Column Temperature ◽  
Relative Standard ◽  
Liquid Chromatographic ◽  
Intercept Bias

Abstract An alternative liquid chromatographic (LC) method was developed and validated for the simultaneous determination of methoxyl and 2-hydroxypropoxyl substituents in hypromellose and hypromellose acetate succinate. The method uses the hydriodic acid cleavage reaction, catalyzed by adipic acid, of the substituted methoxyl and 2-hydroxypropoxyl groups, which are quantitatively converted to iodomethane and 2-iodopropane. The iodomethane and 2-iodopropane are extracted into xylene, the extract is diluted with methanol, and the analytes are separated and assayed by gradient elution using a reversed-phase C18 column. The method is selective and sensitive and has good linearity with values of 0.999 for R2 and 0.25% for the y-intercept bias from 1.39 to 5.55 mg/mL for iodomethane, and 0.999 for R2 and 0.52% for the y-intercept bias from 0.184 to 0.735 mg/mL for 2-iodopropane. The relative standard precisions for this LC method were found to be ± 2.3% for determining methoxyl at the 23.1% (w/w) level, and ± 3.5% for determining 2-hydroxypropoxyl at the 6.7% (w/w) level. Compared with the current gas chromatographic (GC) compendial (JPE) method, the LC assay method has equal or better precision. It was found that both the standard and sample solutions have limited stability (8 h) after preparation. This limited stability has not been reported previously in the literature and may have an impact on the reported accuracy/precision of the literature data for the GC method. The LC method was proven to be robust with respect to variation in derivatization time and temperature, flow rate, and column temperature. It is well suited for the quality control needed in today's fast-paced pharmaceutical laboratories.

scholarly journals Simultaneous Determination of Phenolic Acids and Phthalide Compounds by Liquid Chromatography for Quality Assessment of Rhizoma Cnidii

2009 ◽  
Vol 92 (2) ◽  
pp. 375-381
Author(s):  
M Nurul Islam ◽  
Hye Hyun Yoo ◽  
Chung-Ki Sung ◽  
Mi-Sook Dong ◽  
Young In Park ◽  
...  
Keyword(s):  
Ferulic Acid ◽  
Chlorogenic Acid ◽  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Bioactive Constituents ◽  
Linear Behavior ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract This paper describes a simple, rapid, and validated reversed-phase high-performance liquid chromatographic method developed for the determination of 4 major bioactive constituents, namely, chlorogenic acid, ferulic acid, senkyunolide A, and Z-ligustilide in Rhizoma Cnidii extract. A Capcell Pak C18 chromatographic column (150 4.6 mm, 3 m) was used with mobile phases consisting of 0.1 formic acid, acetonitrile, and methanol at a flow rate of 0.8 mL/min and UV detection at 285 nm. Comprehensive validation of the method included evaluation of linearity, repeatability, recovery, and stability. Excellent linear behavior (r2 >0.99) was observed over the concentration range of 2100 g/mL for the compounds under investigation. Repeatability and accuracy were evaluated by intra- and interday assays; the relative standard deviation (RSD) values were 5.37 and accuracies ranged from 97.1 to 104.9. Recoveries of the compounds ranged from 94.2 to 104.2 with RSD values of 9.50. The developed method was successfully applied to the analysis of ethanolic extracts of Rhizoma Cnidii samples. As a result, the concentrations of chlorogenic acid, ferulic acid, Z-ligustilide, and senkyunolide A were determined to be 0.845.35, 0.451.65, 0.744.39, and 0.321.14 mg/g herb, respectively. Thus, the developed method was found to be accurate and reproducible and is considered suitable for the qualitative and quantitative analysis of Rhizoma Cnidii for bioactive compounds.

Stability Indicating Liquid Chromatographic Method for the Determination of Fenofibrate and its Application to Kinetic Studies

2013 ◽  
Vol 5 (4) ◽  
pp. 1866-1874
Author(s):  
K. Srinivasa Rao ◽  
Keshar N K ◽  
N Jena ◽  
M.E.B Rao ◽  
A K Patnaik
Keyword(s):  
Degradation Products ◽  
Kinetic Studies ◽  
Pharmaceutical Formulations ◽  
Assay Method ◽  
Pharmaceutical Dosage Form ◽  
Stability Indicating ◽  
Zero Order Kinetics ◽  
Relative Standard ◽  
Liquid Chromatographic

A stability-indicating LC assay method was developed for the quantitative determination of fenofibrate (FFB) in pharmaceutical dosage form in the presence of its degradation products and kinetic determinations were evaluated in acidic, alkaline and peroxide degradation conditions. Chromatographic separation was achieved by use of Zorbax C18 column (250 × 4.0 mm, 5 μm). The mobile phase was established by mixing phosphate buffer (pH adjusted 3 with phosphoric acid) and acetonitrile (30:70 v/v). FFB degraded in acidic, alkaline and hydrogen peroxide conditions, while it was more stable in thermal and photolytic conditions. The described method was linear over a range of 1.0-500 μg/ml for determination of FFB (r= 0.9999). The precision was demonstrated by relative standard deviation (RSD) of intra-day (RSD= 0.56– 0.91) and inter-day studies (RSD= 1.47). The mean recovery was found to be 100.01%. The acid and alkaline degradations of FFB in 1M HCl and 1M NaOH solutions showed an apparent zero-order kinetics with rate constants 0.0736 and 0.0698  min−1 respectively and the peroxide degradation with 5% H2O2 demonstrated an apparent first-order kinetics with rate constant k = 0.0202 per min. The t1/2, t90   values are also determined for all the kinetic studies. The developed method was found to be simple, specific, robust, linear, precise, and accurate for the determination of FFB in pharmaceutical formulations.  

Development and Validation of a New Method for the Determination of Anti-hepatitis C Agent Simeprevir in Human Plasma using HPLC with Fluorescence Detection

2020 ◽  
Vol 16 (4) ◽  
pp. 428-435
Author(s):  
Ahmed F.A. Youssef ◽  
Yousry M. Issa ◽  
Kareem M. Nabil
Keyword(s):  
Hepatitis C ◽  
Human Plasma ◽  
Fluorescence Detection ◽  
Internal Standard ◽  
Protein Precipitation ◽  
Assay Method ◽  
Fluorescence Detector ◽  
Limit Of Quantification ◽  
Relative Standard

Background: Simeprevir is one of the recently discovered drugs for treating hepatitis C which is one of the major diseases across the globe. Objective: The present study involves the development of a new and unique High-Performance Liquid Chromatography (HPLC) method using fluorescence detection for the determination of simeprevir (SIM) in human plasma. Methods: Two methods of extractions were tested, protein precipitation using acetonitrile and liquidliquid extraction. A 25 mM dipotassium hydrogen orthophosphate (pH 7.0)/ACN (50/50; v/v), was used as mobile phase and C18 reversed phase column as the stationary phase. The chromatographic conditions were optimized and the concentration of simeprevir was determined by using the fluorescence detector. Cyclobenzaprine was used as an internal standard. Results: Recovery of the assay method based on protein precipitation was up to 100%. Intra-day and inter-day accuracies range from 92.30 to 107.80%, with Relative Standard Deviation (RSD) range 1.65-8.02%. The present method was successfully applied to a pharmacokinetic study where SIM was administered as a single dose of 150 mg SIM/capsule (Olysio®) to healthy individuals. Conclusion: This method exhibits high sensitivity with a low limit of quantification 10 ng mL-1, good selectivity using fluorescence detection, wide linear application range 10-3000 ng mL-1, good recovery and highly precise and validation results. The developed method can be applied in routine analysis for real samples.

Novel Determination of Anti-Hypertensive Combination; Benidipine Hydrochloride and Nebivolol Hydrochloride by High Performance Chromatographic Method

2021 ◽  
pp. 5433-5438
Author(s):  
V.L.N. Balaji Gupta Tiruveedhi ◽  
Venkateswara Rao Battula ◽  
Kishore Babu Bonige ◽  
Tejeswarudu B.
Keyword(s):  
High Performance ◽  
Degradation Products ◽  
Research Work ◽  
Hplc Method ◽  
Assay Method ◽  
Injection Quantity ◽  
Relative Standard ◽  
Nebivolol Hydrochloride ◽  
Concentration Series

This research work was designed to establish and validate a novel stability indicating RP-HPLC method for the combined determination of Benidipine hydrochloride (BHE) and Nebivolol hydrochloride (NHE) in bulk and tablets, dependent on ICH guidelines.The assay method to analyse BHE and NHE was optimized with isocratic elution using acetonitrile: 0.1M acetate buffer (45:55, pH 5.1), Lichrospher ODS RP-18 column and flow pace of 1 ml/min. Total time for single run was 14 min. The injection quantity was 20μl, and was detected at 249nm. The method was verified on a concentration series of 1.25-10μg/ml (NHE) and 1.0-10μg/ml (BHE) for precision, accuracy and linearity. The LOD values were 0.059µg/ml and 0.028µg/ml for NHE and BHE, respectively. The LOQ values were 0.196µg/ml for NHE and 0.094µg/ml for BHE. The recovery percentages were 98.60-100.11% (BHE) and 98.94-101.50% (NHE) with relative standard deviation 0.250-0.694% (BHE) and 0.183-0.400% (NHE). The method was also observed to be efficient, and was sufficiently specific to measure BHE and NHE in the presence of stress-produced degradation products.

Immunofluorescent Staining of Mouse Pancreas for Islet Cell Mass Analysis v1

2021 ◽  
Author(s):  
Islet and Pancreas Analysis Core
Keyword(s):  
Quantitative Determination ◽  
Islet Cell ◽  
Cell Mass ◽  
Immunofluorescent Staining ◽  
Assay Method ◽  
Mass Analysis ◽  
Mouse Pancreas ◽  
Cell Composition ◽  
Diabetes Center

This SOP defines the assay method used by the Vanderbilt Diabetes Center Islet and Pancreas Analysis (IPA) Core for quantitative determination of the islet cell composition and islet cell mass of mouse pancreas by immunofluorescent staining.

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