Validated Stability-Indicating Chromatographic Methods for the Determination of Veralipride in Presence of Its Degradation Products

Two sensitive and selective chromatographic methods were developed and validated for determination of veralipride in presence of its degradation products. Forced degradation studies were performed, using HCl, NaOH and 3% H₂O₂. The first method is based on thin-layer chromatographic separation of the intact drug spot from its degradation, followed by densitometric measurements. The second method is based on isocratic liquid chromatographic separation of the studied drug from its degradation on a reversed phase C₁₈ column. The proposed LC method was utilized to investigate the kinetics of alkaline degradation process of the selected drug at different temperatures.     

Development and Validation of a Stability-Indicating High-Performance Thin-Layer Chromatographic Method for Determination of Pyridostigmine Bromide in the Presence of Its Alkaline-Induced Degradation Product

JPC – Journal of Planar Chromatography – Modern TLC - A validated, sensitive, and highly selective stability-indicating high-performance thin-layer chromatographic (HPTLC) method has...     

High Performance Liquid Chromatographic Determination of Sertraline in Presence of Its Degradation Product

A simple, stability – indicating, reversed phase liquid chromatographic method has been developed for the determination of sertraline in the presence of its oxidative degradation product. Reversed phase chromatography was conducted using a phenyl (250 × 4.6 mm id) stainless steel column at ambient temperature with UV-detection at 226 nm. A mobile phase consisting of potassium dihydrogen phosphate buffer: acetonitrile (50:50, v/v) adjusted to pH 4.5 with phosphoric acid, has been used for the separation of sertraline and its oxidative degradation product at a flow rate of 1 ml/min. The calibration curve was rectilinear over the concentration range of 1–20 μg/ml with a detection limit (LOD) of 0.09 μg/ml, and quantification limit (LOQ) of 0.27 μg/ml. The proposed method was successfully applied for the analysis of sertraline in its tablets, with mean % recoveries of 100.17 ± 0.62 for sertraline in pure form and 100.14 ± 0.68, 100.29 ± .77, and 100.06 ± 0.67 for seserine®, serlift®, and sirto® tablets, respectively. The obtained results were favorably compared with those obtained by a reference method. The drug was exposed to forced alkaline, acidic, hydrolytic, and oxidative degradation according to the ICH Guidelines. Moreover, the method was utilized to investigate the kinetics of the photoinduced oxidative degradation of the drug. The first-order rate constant, half-life time, and activation energy of the degradation reaction were calculated.     

Determination of Atazanavir in the Presence of its Degradation Products by a Stability-Indicating LC Method

A forced degradation study was successfully applied for the development of a stability-indicating assay method for the determination of atazanavir in presence of its degradation products. The method was developed and optimized by analyzing the forcefully degraded samples. Degradation of the drug was done under acidic, alkaline, oxidative, photolytic and thermal stress conditions. The proposed method was able to resolve all of the possible degradation products formed during the stress studies. The major impurities are generated in acidic and alkaline conditions. The product was found stable under thermal, photolytic and oxidative conditions. The developed method was validated for determination of atazanavir, and the method was found to be equality applicable to study the impurities formed during routine and forced degradation of atazanavir.     

Different Chromatographic Methods for the Simultaneous Determination of Vitamin E and Vinpocetine in Their Combined Dosage Form and in the Presence of the Alkaline-Induced Degradation Product of Vinpocetine

JPC – Journal of Planar Chromatography – Modern TLC - Accurate, selective, and sensitive thin-layer chromatography (TLC)—densitometry and reversed-phase high-performance liquid...     

Stability-Indicating Method for the Determination of Hydrochlorothiazide,Benzydamine Hydrochloride and Clonazepam in the Presence of Their Degradation Products

Abstract

Spectrophotometric, colorimetric and densitometric methods for the determination of hydrochlorothiazide, benzydamine hydrochloride and clonazepam in the presence of their degradation products are described. Hydrochlorothiazide was determined in the presence of its degradation products methoxyhydrothiazide, hydroxyhydrothiazide and 5-chloro-2,4-disulfonamidoaniline applying the first and second derivative spectrophotometer at 278.8 nm and 254.4 nm, respectively, while benzydamine hydrochloride was determined in the presence of its toxic photodegradation products 5-hydroxybenzydamine and 2-B-dimethylaminopropyl-l-benzylindalolin-3-one colorimetrically using the acid dye bromophenol red and measuring the absorbance of the chloroform solution of the ion-pair formed at 425nm. Clonazepam was determined densitometrically in the presence of its degradation products carbostyril and 2-amino-2-chloro-5-nitrobenzophenone. The suggested methods determine hydrochlorothiazide, benzydamine hydrochloride and clonazepam in the presence of degradation products with mean accuracies of 99.57±0.51%, 100.04±0.41%, 100.03±0.21% and 99.84±0.34%, respectively. The proposed methods are suitable for stability testing in bulk powder and in pharmaceutical preparations.     

Development and Validation of Chromatographic Methods for the Quantification of Dabigatran Etexilate Mesylate in the Presence of Its Risky Degradation Products

JPC – Journal of Planar Chromatography – Modern TLC - New stability-indicating thin-layer chromatography (TLC)—densitometry and reversed-phase liquid chromatography (RP-LC)...     

Stability-Indicating Chromatographic Methods for Simultaneous Determination of Mosapride and Pantoprazole in Pharmaceutical Dosage Form and Plasma Samples

Simple, sensitive, selective, precise, and stability-indicating thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) methods for the determination of mosapride and pantoprazole in pharmaceutical tablets were developed and validated as per the International Conference on Harmonization guidelines. The TLC method employs aluminum TLC plates precoated with silica gel 60F₂₅₄ as the stationary phase and ethyl acetate/methanol/toluene (4:1:2, v/v/v) as the mobile phase to give compact spots for mosapride (R _f 0.73) and pantoprazole (R _f 0.45) separated from their degradation products; the chromatogram was scanned at 276 nm. The HPLC method utilizes a C18 column and a mobile phase consisting of acetonitrile/methanol/20 mM ammonium acetate (4:2:4, v/v/v) at a flow rate of 1.0 mL min⁻¹ for the separation of mosapride (t _R 11.4) and pantoprazole (t _R 4.4) from their degradation products. Quantitation was achieved with UV detection at 280 nm. The same HPLC method was successfully used in performing calibrations in lower concentration ranges for both drugs in human plasma using ezetimibe as internal standard. The methods were validated in terms of accuracy, precision, linearity, limits of detection, and limits of quantification. Mosapride and pantoprazole were exposed to acid hydrolysis and then analyzed by the proposed methods. As the methods could effectively separate the drugs from their degradation products, these techniques can be employed as stability-indicating methods that have been successively applied to pharmaceutical formulations without interference from the excipients. Moreover the HPLC method was successfully used in the determination of both drugs in spiked human plasma.

     

Stability-Indicating Chromatographic Methods for Simultaneous Determination of Mosapride and Pantoprazole in Pharmaceutical Dosage Form and Plasma Samples

Simple, sensitive, selective, precise, and stability-indicating thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) methods for the determination of mosapride and pantoprazole in pharmaceutical tablets were developed and validated as per the International Conference on Harmonization guidelines. The TLC method employs aluminum TLC plates precoated with silica gel 60F₂₅₄ as the stationary phase and ethyl acetate/methanol/toluene (4:1:2, v/v/v) as the mobile phase to give compact spots for mosapride (R _f 0.73) and pantoprazole (R _f 0.45) separated from their degradation products; the chromatogram was scanned at 276 nm. The HPLC method utilizes a C18 column and a mobile phase consisting of acetonitrile/methanol/20 mM ammonium acetate (4:2:4, v/v/v) at a flow rate of 1.0 mL min^?1 for the separation of mosapride (t _R 11.4) and pantoprazole (t _R 4.4) from their degradation products. Quantitation was achieved with UV detection at 280 nm. The same HPLC method was successfully used in performing calibrations in lower concentration ranges for both drugs in human plasma using ezetimibe as internal standard. The methods were validated in terms of accuracy, precision, linearity, limits of detection, and limits of quantification. Mosapride and pantoprazole were exposed to acid hydrolysis and then analyzed by the proposed methods. As the methods could effectively separate the drugs from their degradation products, these techniques can be employed as stability-indicating methods that have been successively applied to pharmaceutical formulations without interference from the excipients. Moreover the HPLC method was successfully used in the determination of both drugs in spiked human plasma.     

Comparison of Chromatographic Methods for the Determination of Bound Glycerol in Biodiesel

An important fuel criterion for biodiesel is bound glycerol, which is a function of the residual amount of triglycerides and partial glycerides in the biodiesel. Either high-temperature gas chromatography or high performance liquid chromatography can be used for determining these minor but important components in biodiesel. In this paper we have conducted a statistical study on the accuracy of the two methods for ascertaining the bound glycerol in biodiesel fuels obtained from different feedstocks. Analysis of variance showed that with one exception, namely diacylglycerols in some soy oil based biodiesel, there was no statistical difference in bound glycerol for the biodiesel samples analyzed or a difference between methods. Operationally, the high performance liquid chromatographic method is superior to the high temperature gas chromatographic method in that it requires no sample derivatization, has shorter analysis times, and is directly applicable to most biodiesel fuels.     

A Comparison of Chromatographic Methods for the Determination of Deoxynivalenol in Wheat

Liquid chromatography coupled with tandem mass spectrometric detection has gained more importance for mycotoxin determination in recent years. In addition to instrumental improvements, the development of LC-MS-MS has also been a consequence of the availability of stable isotope internal standards, e.g., ¹³C-labelled mycotoxins. Thus, the LC-ESI-MS-MS method using a ¹³C₁₅-deoxynivalenol internal standard as a state-of-the-art technique was selected as a reference procedure for an in-house method comparison study of the determination of deoxynivalenol (DON) in wheat materials. Alternative methods include LC-diode array detection, which is a frequently used routine procedure for DON-analysis, and gas chromatography after trimethylsilylation. For GC application, an electron capture detector and a negative chemical ionisation mass spectrometry detector were used, which have both been well described in the literature. The method comparison was conducted using t test statistics. Additionally, this study also calculates important method performance characteristics, including accuracy, linearity, limit of detection, limit of quantification, recovery, and variation coefficient. Furthermore, this is the first report of a GC-MS method for the determination of DON using a fully carbon-labelled ¹³C₁₅-DON as an IS. The GC-MS using ¹³C₁₅-DON as an IS has produced comparable results to the ¹³C-IS-LC-MS-MS reference method with a similar sensitivity. ECD detection was slightly less sensitive, but is also suited for DON analysis in wheat. Due to the high LOQ, the LC-DAD method seems highly applicable to the measurement of highly contaminated samples.     

A Comparison of Chromatographic Methods for the Determination of Deoxynivalenol in Wheat

Liquid chromatography coupled with tandem mass spectrometric detection has gained more importance for mycotoxin determination in recent years. In addition to instrumental improvements, the development of LC-MS-MS has also been a consequence of the availability of stable isotope internal standards, e.g., ¹³C-labelled mycotoxins. Thus, the LC-ESI-MS-MS method using a ¹³C₁₅-deoxynivalenol internal standard as a state-of-the-art technique was selected as a reference procedure for an in-house method comparison study of the determination of deoxynivalenol (DON) in wheat materials. Alternative methods include LC-diode array detection, which is a frequently used routine procedure for DON-analysis, and gas chromatography after trimethylsilylation. For GC application, an electron capture detector and a negative chemical ionisation mass spectrometry detector were used, which have both been well described in the literature. The method comparison was conducted using t test statistics. Additionally, this study also calculates important method performance characteristics, including accuracy, linearity, limit of detection, limit of quantification, recovery, and variation coefficient. Furthermore, this is the first report of a GC-MS method for the determination of DON using a fully carbon-labelled ¹³C₁₅-DON as an IS. The GC-MS using ¹³C₁₅-DON as an IS has produced comparable results to the ¹³C-IS-LC-MS-MS reference method with a similar sensitivity. ECD detection was slightly less sensitive, but is also suited for DON analysis in wheat. Due to the high LOQ, the LC-DAD method seems highly applicable to the measurement of highly contaminated samples.

     

Stability-Indicating High Performance liquid Chromatographic Determination of Diltiazem Hydrochloride

Abstract

A rapid, selective and accurate high-performance liquid chromatography method (HPLC) for the determination of diltiazem hydrochloride using clonazepam as internal standard is developed. The investigated compounds were eluted from 5 u Micropak MCH-5 reversed phase column at ambient temperature with a mobile phase comprising of acetonitrile-water (48:52%) at pH 3.3 and containing 0. 01M sodium-n-octane sulfonate as an ion pairing substance. The mobile phase was pumped at a flow rate of 1 ml min^?1 and the effluent was monitored at 239 nm. The retention times of the internal standard and diltiazem were at 3 min and 9 min, respectively. A linear relationship was derived between the peak height ratio (diltiazem/clonazepam) and diltiazem concentration over the range 1–10 μg ml^?1. Detection limit for the drug is 0.2 μg ml^?1 at 0.01 aufs. The developed procedure was applied to study the stability of diltiazem in the presence of its degradation products as well as in the presence of formulation excipients.     

Stability-Indicating Method For The Determination Of N-Desmethyldiazepam And Simultaneous Determination Of Its Degradation Products

Abstract

A simple, direct and sensitive spectrophotometric method for the determination of the intact N-desmethyldiazepam in the presence of its degradation products, 2-amino-5-chlorobenzophenone and glycine, is developed. The proposed procedure is based on direct measurement of the absorbance of its acidified methanolic solution at 361 nm. The procedure determines 8–56 mcg ml^?1 of N-desmethyldiazepam with an accuracy of 100.2 ± 0.51%. The proposed procedure retains its accuracy in presence of up to 80% of the different degradation products. The procedure is applied successfully for the determination of N-desmethyldiazepam in bulk powder, tablets and drops.

Simultaneous determination of the different degradation products in the presence of the parent drug is also described. Thus, 2-amino-5-chlorobenzophenone is determined by direct measurement of its methanolic solution at about 380 nm, with an accuracy of 100.4 ± 0.42%. Glycine is determined colorimetrically using ninhydrin reagent in presence of pyridine, with an accuracy of 99.5 ± 0.78%.     

Validated TLC and HPLC Stability-Indicating Methods for the Quantitative Determination of Dapsone

JPC – Journal of Planar Chromatography – Modern TLC - Two stability-indicating chromatographic methods were developed for the analysis of dapsone in presence of its oxidative...     

Stability-Indicating High-Performance Thin-Layer Chromatographic Method for the Simultaneous Determination of Quercetin and Resveratrol in the Lipid-Based Nanoformulation

JPC – Journal of Planar Chromatography – Modern TLC - A simple, sensitive, specific, rapid, and accurate high-performance thin-layer chromatographic (HPTLC) method has been developed...     

两种乳糖酶活力测定方法比较

邻硝基苯-β-D-吡喃半乳糖苷(ONPG)法和双糖酶法是常用的乳糖酶活力测定方法,本文对这两种方法的线性范围、检出限、精密度、准确度和稳定性进行了比较。 结果显示,ONPG法在线性范围、检出限、精密度以及稳定性方面均优于双糖酶法,但此种方法的重复性较差,需要进一步的优化。 对比这两种方法,可为乳糖酶活力测定方法的合理选取提供参考。     

Reversed-Phase Liquid Chromatographic Method for Determination of Daclatasvir Dihydrochloride and Study of Its Degradation Behavior

A simple and selective reversed-phase stability-indicating liquid chromatographic method has been developed and validated for the determination of daclatasvir in drug substance and drug product. Daclatasvir was subjected to acidic, alkaline, oxidative, thermal and photo-degradation study. The LC method was based on isocratic elution of daclatasvir and its degradation products on a reversed-phase C₁₈ Hypersil column using a mobile phase consisting of phosphate buffer (10 mM, 1 mL triethylamine L^?1): acetonitrile (60:40 v/v) at a flow rate of 2 mL min^?1. Quantitation was achieved with UV detection at 312 nm. Linearity, accuracy, and precision were found to be acceptable over the concentration range of 0.75–120 μg mL^?1, with regression coefficient value of 0.9999, and with limit of detection and quantitation of 0.148 and 0.447 μg mL^?1, respectively. Peak purity was checked for principle drug and its alkali induced degradation product, and the pathway of alkaline hydrolysis of daclatasvir was suggested by LC/MS.