A Validated RP-LC Method for Advanced Intermediate of Rabeprazole Sodium

The present paper describes the development of a reversed phase liquid chromatographic method for advanced intermediate of rabeprazole sodium (RBS-1) in the presence of its impurities. Successful separation of RBS-1 from the synthetic impurities achieved on a Inertsil ODS3V C18, 150 mm × 4.6 mm column. The developed LC method was validated with respect to linearity, accuracy, precision, specificity and ruggedness. To the best of our knowledge, a validated stability indicating LC method which separates all the impurities disclosed in this investigation was not published elsewhere.

     

A Validated Stability Indicating RP-LC Method for Nitazoxanide, a New Antiparasitic Compound

The present paper describes stability indicating reverse phase high-performance liquid chromatography (RP-HPLC) assay method for nitazoxanide in bulk drugs. The developed method is also applicable for the related substances determination in bulk drug. The drug substance was subjected to stress conditions of hydrolysis, photolysis and thermal degradation. The considerable degradation of nitazoxanide was observed under base and peroxide hydrolysis. The drug was found to be stable in other stress conditions attempted. The chromatographic separation of the drug was achieved on reversed-phase C-18 column. Eluents were monitored on photo-diode array detector at a wavelength of 240 nm. The mobile phase was aqueous 0.005 M tetra butyl ammonium hydrogen sulphate and acetonitrile (45:55, v/v). In the developed HPLC method, resolution between nitazoxanide and its potential impurities, namely Imp-A (5-nitro-1,3-thiazol-2-amine), Imp-B (N-(5-nitro-1,3-thiazol-2-yl) acetamide) and Imp-C (2-{[(5-nitro-1,3-thiazol-2-yl) amino] carbonyl} phenyl 2-(acetyloxy) benzoate) was found greater than three. The developed RP-HPLC method was validated with respect to response function, accuracy, precision, specificity, stability of analytical solutions and robustness. Also to determine related substances and assay determination of nitazoxanide that can be used to evaluate the quality of regular production samples. The developed method can also be conveniently used for the assay determination of nitazoxanide in pharmaceutical formulations.     

A Validated, Specific Stability-Indicating RP-LC Method for Moxifloxacin and Its Related Substances

A validated, specific, stability-indicating reversed-phase liquid chromatographic method has been developed for quantitative analysis of moxifloxacin and its related substances in bulk samples and pharmaceutical dosage forms in the presence of degradation products and process-related impurities. Forced degradation studies were performed on bulk samples of moxifloxacin, in accordance with ICH guidelines, using acidic, basic, and oxidizing conditions, and thermal and photolytic stress, to show the stability-indicating power of the method. Significant degradation was caused by oxidative stress and by basic conditions; no degradation was observed under the other stress conditions. The method was optimized by analysis of the samples generated during the forced degradation studies and sample solutions spiked with the impurities. Good resolution between the analyte peak and peaks corresponding to process-related impurities and degradation products was achieved on a C₁₈ column with a simple linear mobile phase gradient prepared from aqueous sodium dihydrogen orthophosphate dihydrate containing triethylamine, pH adjusted to 3.0 with orthophosphoric acid, and methanol. Detection was performed at 240 nm. Limits of detection and quantification were established for moxifloxacin and its process related impurities. When the stressed test solutions were assayed against moxifloxacin working standard solution the mass balance was always between 99.3 and 100.1%, indicating the method was stability-indicating. The method was validated in accordance with ICH guidelines, and found to be suitable for checking the quality of bulk samples of moxifloxacin at the time of release of a batch and during storage (long term and accelerated stability testing was conducted).     

Simple Rapid Validated RP-LC Method for the Estimation of Flurbiprofen in Rabbit Serum and Aqueous Humor

Abstract

New reversed-phase liquid chromatographic methods, with UV detection, were developed for the quantitative estimation of flurbiprofen in rabbit blood serum and aqueous humor. The mobile phase and other chromatographic conditions were optimized to minimize interference from biological matrix and at the same time provide sufficient sensitivity for the method to be adopted for in vivo studies of ophthalmic formulations of flurbiprofen. Acetonitrile was used to precipitate proteins from serum or aqueous humor during sample preparation. A mobile phase of methanol: acetonitrile: phosphate buffer pH 5.6 (40:20:40) was employed with UV detection at 248 nm for estimation of drug in both the biological matrix. The retention time and asymmetry factor for the proposed method of estimation in serum and aqueous humor was found to be 3.1312±0.0101 min and 1.1310±0.0091 respectively. The linear regression equations obtained by least square regression method, were Area (µV sec) = 52.27 × Conc. (in ng/ml)–1618.70 in serum and Area (µV sec) = 61.79 × Conc. (in ng/ml) ? 783.24 in aqueous humor. The results of analysis were treated statistically, as per ICH guidelines for validation of analytical procedures, USP-2003, and by recovery studies. The results were found to be accurate, reproducible and free from interference. The developed methods were further used for estimation of flurbiprofen in rabbit serum and aqueous humor following single topical administration of in-house aqueous drop and market formulation to rabbit eye.     

LC Determination of Isosorbide-5-Mononitrate in Human Plasma

A simple, sensitive, selective and cost effective LC–UV method was developed for determination of isosorbide mononitrate in human plasma using guaifenesin as an internal standard. Isosorbide mononitrate in plasma was extracted by a single step liquid extraction using tert-butyl methyl ether and chromatographed on a C18 column using water and acetonitrile (80:20 v/v) as mobile phase. The method was validated and exhibited a linear range from 51.6 to 2064.4 ng mL^?1. The inter- and intra-assay accuracy ranged from 97.2–102.7 to 94.2–105.5%, respectively, with precision less than 10% in both the cases. The LLQ was 51.6 ng mL^?1. The validated method was applied to the quantitation of isosorbide mononitrate from plasma samples in a pharmacokinetic study.     

Stability Indicating RP-LC Method for the Determination of Gemifloxacin Mesylate

The present study describes the degradation of gemifloxacin mesylate under different International Conference on Harmonization prescribed stress conditions (hydrolysis, oxidation, dry and wet heat and photolysis) and application of a specific and selective stability-indicating reversed-phase liquid chromatography assay. Separation of drug and degradation products was successfully achieved on a HiQ-SiL C₈ column using 10 mM potassium dihydrogen orthophosphate (pH adjusted to 3.0 with o-phosphoric acid)–acetonitrile (65:35, v/v) at a flow rate of 1 mL min⁻¹ and detection at 273 nm.

     

A Validated, Specific, Stability-Indicating RP-LC Method for Analysis of Gatifloxacin in the Presence of Degradation Products and Process-Related Impurities

A validated, specific, stability-indicating reversed-phase liquid chromatographic method has been developed for quantitative analysis of gatifloxacin, its degradation products, and its process-related impurities in bulk samples and in pharmaceutical dosage forms. Forced degradation of gatifloxacin bulk sample was conducted in accordance with ICH guidelines. Acidic, basic, neutral, and oxidative hydrolysis, thermal stress, and photolytic degradation were used to assess the stability-indicating power of the method. Substantial degradation was observed during oxidative hydrolysis. No degradation was observed under the other stress conditions. The method was optimized using samples generated by forced degradation and sample solution spiked with impurities. Good resolution of the analyte peak from peaks corresponding to process-related impurities and degradation products was achieved on a C₁₈ column by use of a simple linear mobile-phase gradient prepared from mixtures of acetonitrile and an aqueous solution of sodium dihydrogen orthophosphate dihydrate and triethylamine adjusted to pH 6.5 with orthophosphoric acid. Detection was performed at 240 nm. Limits of detection and quantification were established for gatifloxacin and its process-related impurities. When the stressed test solutions were assayed by comparison with gatifloxacin working standard the mass balance was always close to 99.3%, indicating the method was stability-indicating. Validation of the method was performed in accordance with ICH requirements. The method was found to be suitable for checking the quality of bulk samples of gatifloxacin at the time of batch release and also during storage.     

Flavone Glycoside Based Validated RP-LC Method for Quality Evaluation of Prishniparni (Uraria picta)

An LC method is developed for the quantitation of rhoifolin in Uraria picta, a plant of high usage frequency in all Asian traditional systems of medicine. An isocratic RP-LC method using C₁₈ column, UV detection 265 nm and specificity with PDA and MS is speeding up, reliable and comprehensive analysis of rhoifolin in U. picta. Good linearity was obtained in the working range (0.02–0.10 mg mL^?1), with correlation coefficients >0.99. LOD and LOQ were 2.33 and 7.69 ng, respectively. The method was validated following international guidelines. The described method can be utilized for assays and stability tests of U. picta extracts as well as Ayurvedic drugs based on Prishniparni.     

A Validated LC Method for Determination of Trace Impurities in Technical Triadimefon

A simple and sensitive liquid chromatography with ultraviolet detection (LC?CUV) method was developed for the determination of three impurities with a content over 0.1% (w/w) in technical triadimefon. A Gemini C₁₈ column (5 ??m, 250 mm × 4.6 mm i.d.) was used for the chromatographic separations. The samples were separated by gradient elution with water (solvent A) and methanol (solvent B) using the following conditions: 70% A isocratic for 12 min, linear to 0% A within 8 min, and isocratic for 10 min at 0% A with a flow rate of 1.0 mL min^?1. Chromatograms were recorded at an absorption wavelength of 280 nm. The chromatographic resolutions between triadimefon and its potential impurities A, B, and C were greater than 3. The developed LC method was validated with respect to linearity, accuracy, precision, and robustness. This method was successfully applied to analyze the impurities in commercial technical triadimefon. In addition, the structures of the three impurities were identified to be (A) 4-chlorophenol, (B) 1-(2,4-dichlorophenoxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone, and (C) 1,1-bis(4-chlorophenoxy)-3,3-dimethyl-2-butanone.     

A Novel RP-LC Method for Determination of pK a Values of Some Anticancer Agents and Their Assay

A simple, reliable, and rapid RP-LC method has been developed for the determination of some anticancer drugs (daunorubicin, doxorubicin and vincristine sulfate) in their dosage forms and human urine. These compounds are well separated on a C18 column using the mobile phase consisting of a mixture of acetonitrile (50:50; v/v) at a flow rate of 1.5 mL min^?1. The analyte peaks were detected at 235 nm for doxorubicin and daunorubicin, and 220 nm for vincristine. Linearity was obtained in different concentration ranges between 0.10 and 12 μg mL^?1 for all compounds. Good sensitivity for all analytes was observed with DAD detection. LOD and LOQ of the method were found satisfying. The proposed method has been extensively validated in accordance with ICH guidelines and obtained results proved that the proposed method was precise, accurate, selective, and sensitive for simultaneous analysis of studied compounds. All analytical procedures including sample preparation, flow rate, and run time were at low levels. Also, pK _a values were determined using the dependence of the retention factor on the pH of the mobile phase. The effect of the mobile phase composition on the ionization constant was studied by measuring the pK _a at different methanol–water mixtures, ranging between 45 and 60 % (v/v).     

A Novel RP-LC Method for Determination of pK a Values of Some Anticancer Agents and Their Assay

A simple, reliable, and rapid RP-LC method has been developed for the determination of some anticancer drugs (daunorubicin, doxorubicin and vincristine sulfate) in their dosage forms and human urine. These compounds are well separated on a C18 column using the mobile phase consisting of a mixture of acetonitrile (50:50; v/v) at a flow rate of 1.5 mL min⁻¹. The analyte peaks were detected at 235 nm for doxorubicin and daunorubicin, and 220 nm for vincristine. Linearity was obtained in different concentration ranges between 0.10 and 12 μg mL⁻¹ for all compounds. Good sensitivity for all analytes was observed with DAD detection. LOD and LOQ of the method were found satisfying. The proposed method has been extensively validated in accordance with ICH guidelines and obtained results proved that the proposed method was precise, accurate, selective, and sensitive for simultaneous analysis of studied compounds. All analytical procedures including sample preparation, flow rate, and run time were at low levels. Also, pK _a values were determined using the dependence of the retention factor on the pH of the mobile phase. The effect of the mobile phase composition on the ionization constant was studied by measuring the pK _a at different methanol–water mixtures, ranging between 45 and 60 % (v/v).

     

A Validated High-Performance Thin-Layer Chromatographic Method for the Determination of Azathioprine from Pharmaceutical Formulation

JPC – Journal of Planar Chromatography – Modern TLC - A simple, specific, and precise high-performance thin-layer chromatographic (HPTLC) method for the analysis of azathioprine, both...     

A Validated LC Method for Simultaneous Determination of Three Major Components in Entada phaseoloides

A high performance liquid chromatography method was developed for the simultaneous determination of three major active constituents in Entada phaseoloides, namely phaseoloidin (1), entadamide A (2), entadamide A-β-d-glucopyranoside (3), respectively. The samples were separated on an Aglient Eclipse XDB-C₁₈ column with gradient elution of acetonitrile and 0.3% phosphoric acid (v/v) at a flow rate of 1.0 mL min^?1 and detected at 280 nm. The three target compounds were completely separated within 10 min. All calibration curves showed good linearity (r > 0.9999) within test ranges. The reproducibility was evaluated by intra- and inter-day assays and RSD values were less than 1.04%. The recoveries were between 97.15 and 101.95%. The method was successfully applied to the analysis of three compounds in 22 commercial samples of E. phaseoloides. The results indicated that the developed LC assay was readily utilized as a quality control method for E. phaseoloides.     

A Validated Method for the Determination of Neonicotinoid,Pyrethroid and Organochlorine Residues in Human Milk

Exposure to pesticides in the environment is sensitively indicated by the concentration of these chemicals in human milk. However, to the best of our knowledge, detection methods in human milk for the relatively new class of pesticides, neonicotinoids, are yet to be validated. We developed a method of detection of neonicotinoids in human milk, together with two other classes of pesticides, pyrethroids and organochlorines. Neonicotinoids and pyrethroids are emerging pesticides that are replacing older and more persistent chemicals such as organochlorines. We optimized a procedure for extraction of these chemicals from whole milk and report our solutions to the problems of interference by co-extracted substances. The clean-up method was optimized using a minimum amount of PSA (50 mg) and MgSO₄ (150 mg). This was followed by GC–MS/MS analysis (for organochlorines and pyrethroids) and LC–MS/MS (for neonicotinoids). The method was validated following SANTE/11945/2015 guidelines at concentrations 10, 20 and 100 ng g^?1. Limits of quantification were obtained at ≤ 2 ng g^?1 for all pesticides and lowest validated level were 10 ng g^?1, with measurement uncertainty between 0.47 and 2.6 ng g^?1. Average recovery ranged from 84 to 102% and for most compounds was found to be more satisfactory than the original QuEChERS, AOAC 2007.01 acetate buffer method and modified QuEChERS methods. The relative standard deviation was less than 16%. The method was successfully utilized for the analysis of human milk samples from Nadia, West Bengal and was found positive for organochlorines and negative for neonicotinoids and pyrethroids.     

Validated HPLC Method for Separation and Determination of Terbutaline Enantiomers

Abstract

A simple, rapid, and validated method for separation and determination of terbutaline enantiomers was developed. Terbutaline was separated and determined on a Vancomycin Chirobiotic V column (250 × 4.6 mm), using a mixture of methanol, acetic acid, and triethylamine (100:0.1:0.1% v/v/v) as a mobile phase at 20°C and at a flow rate of 1 ml/min. The UV detector was set to 276 nm. Acetyl salicylic acid (aspirin) was used as an internal standard. The applied high-performance liquid chromatography (HPLC) method allowed separation and quantification of terbutaline enantiomers with good linearity (r > 0.999) in the studied range. The relative standard deviations (RSD) were 1.10 and 1.32% for the terbutaline enantiomers with accuracy of 99.80 and 99.55. The limit of detection and limit of quantification of terbutaline enantiomers were found to be 0.05 and 0.10 µg · ml^?1, respectively. The method was validated through the parameters of linearity, accuracy, precision, and robustness. The HPLC method was applied for the quantitative determination of terbutaline in pharmaceutical formulations.     

A Validated Stability-Indicating LC Method for Zonisamide

A simple, isocratic, rapid, and accurate reversed-phase high-performance liquid chromatographic method has been established for quantitative determination of zonisamide. The method is also applicable to determination of related substances in the bulk drug. Chromatographic separation was achieved on a 250 mm × 4.6 mm, 5-μm particle, C₁₈ column; the mobile phase was a 70:30 (v/v) mixture of 0.1% (v/v) aqueous triethylamine, adjusted to pH 2.5 with dilute orthophosphoric acid, and acetonitrile. Chromatographic resolution of zonisamide from its potential impurity, A, was found to be >2. The limits of detection and quantification of zonisamide and impurity A were 0.04 and 0.12 μg mL^?1, respectively, for 20 μL injection volume. Recovery of zonisamide ranged from 98.5 to 101.2% and recovery of impurity A from a sample of zonisamide ranged from 97.4 to 102.7%. The method was validated for linearity, accuracy, precision, and robustness.     

A Simple and Validated LC Method for the Simultaneous Determination of Three Compounds in Mikania laevigata Extracts

The Mikania genus is widely known as guaco and is used to treat fever, rheumatism, influenza and respiratory diseases. This article deals with the simultaneous quantification of three commercially available phenolic markers (o-coumaric acid, coumarin and syringaldehyde) in M. laevigata extracts, through LC-PDA. The validation data show that the method is specific, accurate, precise and robust, and also indicative of the stability of guaco extract. The method was linear, over a range of 1.25–20.0 μg mL⁻¹ for o-coumaric acid, 2.5–40.0 μg mL⁻¹ for coumarin, and 0.25–4.0 μg mL⁻¹ for syringaldehyde. The range of recovery was 94.3–96.4% for all the components, at a level of 100%.

     

A Validated Stability-Indicating LC Method for Zonisamide

A simple, isocratic, rapid, and accurate reversed-phase high-performance liquid chromatographic method has been established for quantitative determination of zonisamide. The method is also applicable to determination of related substances in the bulk drug. Chromatographic separation was achieved on a 250 mm × 4.6 mm, 5-μm particle, C₁₈ column; the mobile phase was a 70:30 (v/v) mixture of 0.1% (v/v) aqueous triethylamine, adjusted to pH 2.5 with dilute orthophosphoric acid, and acetonitrile. Chromatographic resolution of zonisamide from its potential impurity, A, was found to be >2. The limits of detection and quantification of zonisamide and impurity A were 0.04 and 0.12 μg mL⁻¹, respectively, for 20 μL injection volume. Recovery of zonisamide ranged from 98.5 to 101.2% and recovery of impurity A from a sample of zonisamide ranged from 97.4 to 102.7%. The method was validated for linearity, accuracy, precision, and robustness.

     

A Validated TLC-Densitometric Method for the Simultaneous Determination of Formoterol Fumarate and Budesonide in Pressurized Metered-Dose Inhaler

JPC – Journal of Planar Chromatography – Modern TLC - A simple and robust thin-layer chromatography (TLC) method has been developed and validated for the simultaneous quantitative...     

Determination of the Monoclonal Antibody Tocilizumab by a Validated Micellar Electrokinetic Chromatography Method

Chromatographia - Tocilizumab is a monoclonal antibody used in the treatment of several inflammatory and autoimmune diseases as well as cancers. Tocilizumab improves clinical outcomes and reduce...