Simultaneous RP-LC Determination of Losartan Potassium, Ramipril, and Hydrochlorothiazide in Pharmaceutical Preparations

A simple, rapid, and precise reversed-phase high-performance liquid chromatographic method has been developed for simultaneous determination of losartan potassium, ramipril, and hydrochlorothiazide. The three drugs were separated on a 150 mm × 4.6 mm i.d., 5 μm particle, Cosmosil C₁₈ column. The mobile phase was 0.025 m sodium perchlorate–acetonitrile, 62:38 (v/v), containing 0.1% heptanesulphonic acid, pH adjusted to 2.85 with orthophosphoric acid, at a flow rate of 1.0 mL min⁻¹. UV detection was performed at 215 nm. The method was validated for linearity, accuracy, precision, and limit of quantitation. Linearity, accuracy, and precision were acceptable in the ranges 35–65 μg mL⁻¹ for losartan, 1.75–3.25 μg mL⁻¹ for ramipril, and 8.75–16.25 μg mL⁻¹ for hydrochlorothiazide.     

Simultaneous Spectrophotometric Determination of Hydrochlorothiazide and Pharmaceutical Preparations

Abstract

We developed three methods for the simultaneous determination of amiloride (AMI) and hydrochlorothiazide (HCT): zero-crossing, derivative quotient spectra with normalized divisor and multiple linear regression (MULTIC) methods. The two first methods use the derivative spectrophotometry, and the last one uses the absorbance measurement. The three methods were used to determine both compounds in synthetic mixtures and pharmaceutical preparations with errors less than 5% and 15%, respectively.     

Simultaneous Determination of Rosiglitazone and Metformin in Pharmaceutical Preparations by LC

In the present study, a novel, fast and simple liquid chromatographic method was developed and validated for the simultaneous determination of rosiglitazone and metformin in pharmaceutical preparations. The separation was achieved on a phenyl column (250 × 4.6 mm i.d., 5 μm) using a mobile phase composed of acetonitrile:10.0 mM phosphate buffer pH 5.5 (70:30, v/v). The flow rate was 1 mL min⁻¹. UV detection was performed at 245 nm and verapamil was used as internal standard. The developed method was validated in terms of stability, specificity, sensitivity, linearity, accuracy, precision and robustness. The limit of quantification was 0.02 μg mL⁻¹ for both drugs. The method developed was successfully applied to the simultaneous determination of rosiglitazone and metformin in pharmaceutical preparations. The results were compared to two methods reported in the literature and no significant difference was found statistically.     

Simultaneous Determination of Atenolol and Chlorthalidone in Pharmaceutical Preparations by Capillary-Zone Electrophoresis

Abstract

A capillary zone electrophoresis (CZE) method for the simultaneous determination of the β-blocker drugs atenolol and chlorthalidone in pharmaceutical formulations has been developed. The CZE separation was performed under the following conditions: capillary temperature, 25°C; applied voltage, 25 kV; 20 mM H₃PO₄–NaOH running buffer (pH 9.0); and detection wavelength, 198 nm. Phenobarbital was used as internal standard. The method was validated and showed not only good precision and accuracy but also good robustness. The method has been successfully applied to the simultaneous determination of both atenolol and chlorthalidone in pharmaceutical tablets.     

卡尔曼滤波-分光光度法用于复方雷琐辛涂剂中苯酚与间苯二酚的测定

本文研究了卡尔曼滤波-分光光度法及其在多组分混合物同时光度测定中的应用。测定复方雷琐辛涂剂中苯酚与间苯二酚,平均回收率分别为100.86%与98.76%。     

Simultaneous RP-LC Determination of Additives in Soft Drinks

A reverse-phase HPLC method for the simultaneous determination of the main artificial sweeteners, preservatives and dyes present in soft drinks is proposed. It involves the use of a 10 μm LiChrosorb RP18 column and a binary eluent consisting of aqueous 0.1 M phosphate buffer (pH 4.0) added with methanol, according to a suitable gradient elution program. Good separations were obtained within less than 20-min run-time, with a satisfactory precision. The sensitivity of spectrophotometric detection was optimised by adopting a wavelength switching technique, thus achieving for all the additives considered detection limits ranging from 0.1 to 3.0 mg L^?1, well below the maximum permitted levels. The method was applied to some commercial soft drinks, whose analysis required minimum pre-treatment before direct injection.     

Benzocaine Determination in Pharmaceutical Preparations

Abstract

A new sensitive method for rapid and accurate determination of benzocaine via hydroxamic acid formation is described. The solution of hydroxylamine hydrochloride is reacted with benzocaine in alkaline medium to give corresponding hydroxamic acid (II) which forms the purple coloured complex with FeCl₃ in acidic medium, having a maximum absorbance at 530 nm. The commonly present additives such as Tyrothricin, Propylene glycol, Glycerin do not show any interference except Quiniodochlor whose interference was eliminated by extracting it with alcohol and removal of waxy substances with a mixture of water and HCL (17.5 :2.5).     

Simultaneous Determination of Enalapril and Losartan in Pharmaceutical Preparations by UV Spectrophotometry and LC

The simultaneous determination of enalapril (Ena) and losartan (Los) in solid dosage forms were done by two methods. The first method involves spectrophotometric determination using the simultaneous equation method at 222 and 250 nm for Ena and Los, respectively. The second method involved an RP-LC method of analysis using methanol:water:acetonitrile (45:35:20% v/v) as the mobile phase. Both methods were satisfactorily validated as per ICH guidelines.     

Simultaneous Determination of Cefuroxime Axetil and Cefuroxime in Pharmaceutical Preparations by Thin-Layer Chromatography and Densitometry

Summary Conditions have been established for identification and quantification of cefuroxime axetil and cefuroxime by thin-layer chromatography and densitometry. Good separation of these compounds was achieved on silica gel by use of chloroform–ethyl acetate–glacial acetic acid–water, 4:4:4:1 (v/v), as mobile phase. UV densitometry was used to detect spots on chromatograms. Under these conditions the limits of detection for cefuroxime axetil and cefuroxime were 40 ng and 30 ng, respectively. Recoveries of cefuroxime axetil and cefuroxime were 99.93% and 97.94%, respectively.     

Simultaneous Determination of Pioglitazone,Metformin, and Glimepiride in Pharmaceutical Preparations using HPTLC Method

JPC – Journal of Planar Chromatography – Modern TLC - A simple, precise, and accurate high-performance thin-layer chromatography (HPTLC) method for the simultaneous determination of...     

Simultaneous Determination of 2-Imidazolines and Other Pharmaceutical Substances in Commercial Preparations by High-Performance Liquid-Chromatography

Abstract

A rapid HPLC method has been presented for the determination of some 2-imidazolines in several liquid or semi-solid commercial preparations. Two of the active ingredients were determined simultaneously whereas others were determined in the presence of dexamethasone and excipients. From the sample solutions no interference was observed on the chromatograms. Linearity and precision of the method have been assessed. The assay results obtained for various formulations were in accord with the declared amount.     

Simultaneous Determination of Losartan Potassium, Atenolol and Hydrochlorothiazide in Pharmaceutical Preparations by Stability-Indicating UPLC

A stability-indicating UPLC method was developed for the simultaneous quantitative determination of losartan potassium, atenolol, and hydrochlorothiazide in pharmaceutical dosage forms in the presence of degradation products. The separation was achieved on a simple isocratic method (water: acetonitrile: triethyl amine: ortho phosphoric acid (60:40:0.1:0.1, v/v) at 0.7 mL min^?1, a detection wavelength of 225 nm). The retention times of losartan potassium, atenolol, and hydrochlorothiazide were 2.3, 0.6 and 0.9 min. The total runtime was 3 min. Losartan potassium, atenolol, and hydrochlorothiazide were subjected to different ICH prescribed stress conditions. The method was validated with respect to linearity, accuracy, precision, robustness and ruggedness.     

A Simple Liquid Chromatographic Method for the Simultaneous Determination of Antidepressants in Pharmaceutical Preparations

Fluoxetine (FT), fluvoxamine (FX), sertraline (ST) and trazodone (TD) are new type of antidepressants acting as selective serotonin reuptake inhibitors (SSRIs). In structures, they all have chromophore and can be easily monitored by UV absorption spectrophotometry. A simple isocratic high‐performance liquid chromatographic method with ultraviolet detection (215 nm) was developed for the simultaneous quantification of FT, FX, ST and TD. The determination range of the method is over 10.0–400.0 μM for each drug. The detection limits (S/N = 3, injection 20 μL) are about 0.1 μM for TD, 0.2 μM for FT, FX and ST. The relative standard deviation and relative error of the method for intra‐ and inter‐day analyses of FT, FX, ST and TD were all below 3.7%. Application of the method to the analysis of FT, FX or ST in pharmaceutical product proved feasible. The method could be used for the quality control assay of the analytes in bulk and in formulations.     

TLC-Densitometric Determination of Azithromycin in Pharmaceutical Preparations

JPC – Journal of Planar Chromatography – Modern TLC - A thin-layer chromatographic method with densitometric detection has been established for quantification of azithromycin in...     

Spectrophotometric Determination of Metoclopramide in Pharmaceutical Preparations

A simple and rapid spectrophotometric method for the determination of metoclopramide is described. The method is based upon simple diazotization reactions with nitrite and aniline as the coupling reagent. The absorbance was measured at 410 nm. The method was optimized for acidity, the amount of reagents required, and the amount of sodium hydroxide. The range of linearity was 0.5–12.0 µg/mL. The method was successfully applied to the determination of metoclopramide in pharmaceutical preparations without any interference from common excipients.__________From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 7, 2005, pp. 711–714.Original English Text Copyright © 2005 by Shah, Rasul Jan, Azam Khan, Amin.The text was submitted by the authors in English.     

Simultaneous RP-LC Determination of Ketorolac and its Piperazinylalkyl Ester Prodrugs

A simple, rapid and selective RP-HPLC method was developed and validated for the determination of ketorolac and five piperazinylalkyl ester prodrugs. A binary isocratic mobile phase composed of a mixture of 65:35 (v/v) 0.02 M phosphate buffer (pH 5.4) and acetonitrile was used on a C₁₈ column (125 × 4 mm, 5 μm). The injection volume was 25 μL and the detection wavelength was 314 nm and the flow rate was 1.5 mL min⁻¹. The method exhibited excellent linearity with R ² of no less than 0.999 and intra-assay and inter-assay precision that were less than the maximum amount allowed according to Horwitz equation. The accuracy was found to be within the allowed ±15%. The limits of detection for the analytes were between 0.060 and 0.220 μg mL⁻¹ and the limits of quantification were between 0.183 and 0.667 μg mL⁻¹. This method was used successfully for the study of the solubility, stability and partition coefficients of piperazinylalkyl ester prodrugs of ketorolac.     

Solid-Phase Extraction and High-Performance Liquid Chromatography for Simultaneous Determination of Important Bioactive Ginsenosides in Pharmaceutical Preparations

A robust method based on high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection has been developed for simultaneous determination of six important ginsenosides (Rg1, Re, Rb1, Rc, Rb2, and Rd) in pharmaceutical preparations. For sample preparation, simple and efficient extraction by ultrasonication, combined with solid-phase extraction (SPE) for clean-up, was effective without consuming large amounts of solvent. Chromatographic separation was performed on an ODS column with optimized gradient elution by means of a dual-solvent-pumping system. The validated method results in excellent separation, and quantitative determination is highly precise and accurate. The problem of co-elution of ginsenosides Rg1 and Re is also solved, with good resolution (R_S approx. 1.5). Intraday variation was between 0.2 and 4.4% and interday variation was between 0.4 and 6.5% (n=5 for both). The accuracy was satisfactory—in the range 93.9 to 103.4% from replicate evaluation at three different spiking concentrations. Overall limits of detection based on a typical injection volume of 5 μL were from 1.16 to 1.58 ng μL⁻¹. The validated method enabled complete assessment for quality control of ginseng samples. The technique may be performed with less sample preparation and, consequently, reduced possibility of sample loss.     

主成分分析-紫外光谱法同时测定四种维生素B

采用主成分分析法(PCA)完成对多组分样品分析的建模及解析研究,用于处理紫外光谱数据,实现了维生素B_1、B_2及B_6及烟酰胺四组分的同时测定,结果可靠,操作简便。     

RP-LC Simultaneous Determination of Nebivolol Hydrochloride and Amlodipine Besilate in Bi-Layer Tablets

A simple and rapid LC method was developed and validated for simultaneous estimation of nebivolol and amlodipine in a bi-layer tablet formulation. Efficient chromatographic separation was achieved on (USP L10) Hypersil BDS cyano, 5 μm, 250 mm × 4.6 mm column with simple mobile phase composition delivered in isocratic mode. The method had requisite accuracy, selectivity, sensitivity, robustness and precision to assay nebivolol and amlodipine in pharmaceutical dosage form. Degradation products resulting from the stress studies did not interfere with the detection of nebivolol and amlodipine, these peaks remained pure and thus proved to be stability indicating. The mass balance of the stressed sample was in the range 99.0–100.2% for amlodipine and 99.3–100.3% for nebivolol.     

Simultaneous Determination of Nine Major Flavonoids in Sophora flavescens by RP-LC

A liquid chromatographic method was applied to determine trifolirhizin, kushenol K, kushenol L, kushenol N, kushenol X, kurarinone, norkurarinone, isokurarinone and kushenol A in the roots of Sophora flavescens, namely Kushen in China. The samples were separated on a YMC-C₁₈ column (250 × 4.6 mm, 5 μm) with a gradient of methanol and 0.3% aqueous acetic acid (v/v) at a flow rate of 0.8 mL min^?1 and detected at 295 nm. The complete separation was achieved within 45 min for the nine major flavonoids. All calibration curves expressed good linearity (r ² > 0.999) within the test range. The recovery of this method was 92.3–106.9%. The assay was successfully applied to the quantification of nine flavonoids in 26 samples of Kushen. The results indicated that this developed LC assay could be readily utilized as a quality control method for the Chinese herb medicine Kushen.