Simultaneous Determination of Caffeine and Paracetamol in Commercial Formulations Using Greener Normal-Phase and Reversed-Phase HPTLC Methods: A Contrast of Validation Parameters

There has been no assessment of the greenness of the described analytical techniques for the simultaneous determination (SMD) of caffeine and paracetamol. As a result, in comparison to the greener normal-phase high-performance thin-layer chromatography (HPTLC) technique, this research was conducted to develop a rapid, sensitive, and greener reversed-phase HPTLC approach for the SMD of caffeine and paracetamol in commercial formulations. The greenness of both techniques was calculated using the AGREE method. For the SMD of caffeine and paracetamol, the greener normal-phase and reversed-phase HPTLC methods were linear in the 50–500 ng/band and 25–800 ng/band ranges, respectively. For the SMD of caffeine and paracetamol, the greener reversed-phase HPTLC approach was more sensitive, accurate, precise, and robust than the greener normal-phase HPTLC technique. For the SMD of caffeine paracetamol in commercial PANEXT and SAFEXT tablets, the greener reversed-phase HPTLC technique was superior to the greener normal-phase HPTLC approach. The AGREE scores for the greener normal-phase and reversed-phase HPTLC approaches were estimated as 0.81 and 0.83, respectively, indicated excellent greenness profiles for both analytical approaches. The greener reversed-phase HPTLC approach is judged superior to the greener normal-phase HPTLC approach based on numerous validation parameters and pharmaceutical assays.     

Determination of Abacavir, Lamivudine and Zidovudine in Pharmaceutical Tablets, Human Serum and in Drug Dissolution Studies by HPLC

A simple, accurate, precise and fully automated method for the simultaneous determination of abacavir, lamivudine and zidovudine in pharmaceutical tablets, human serum samples and drug dissolution studies has been developed. Separation was performed on a 5 μm Zorbax^® C₁₈ column (150 × 4.6 mm ID) with methanol:water:phosphate buffer at pH 5.65 (80:10:10; v/v/v) isocratic elution in less than 7 min with a flow rate of 0.6 mL min^?1.Good sensitivity for all analytes was observed with UV detection at 275 nm. The method allowed quantitation over the 500–3,000 ng mL^?1 range for abacavir and 500–5,000 ng mL^?1 range for lamivudine and zidovudine. The method has been applied, without any interference from excipients or endogenous substances, for the simultaneous determination of these three compounds in tablets. Human serum and drug dissolution studies.     

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 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 Tinidazole and Furazolidone in Suspension by HPTLC and HPLC

Abstract

High performance thin layer chromatographic (HPTLC) and high performance liquid chromatographic (HPLC) methods were developed for the simultaneous determination of Tinidazole and Furazolidone in suspension.

In the HPTLC method the separation of Tinidazole and Furazolidone was carried out on silica gel 60F₂₅₄ HPTLC glass plate using chloroform:methanol:ammonia (9:1:0.1 v/v) as a mobile phase. Rf values obtained were 0.63 and 0.79 for Furazolidone and Tinidazole respectively. Densitometric evaluation was done at 335 nm. Linearity was obtained within the concentration range 10–50 μg/ml and 3.5–17.5 μg/ml for Tinidazole and Furazolidone respectively.

The second method is based on high performance liquid chromatography on a reversed phase column (μ Bondapak C₁₈) using a mobile phase comprised of water: acetonitrile: triethylamine (80:20:0.1 v/v) adjusted to pH = 3.0 with dil. phosphoric acid. Retention times were 5.24 and 7.82 min for Tinidazole and Furazolidone respectively at a flow rate of 1.5 ml/min. Detection was done at 335 nm. Linearity was obtained within the concentration range 30–180 μg/ml and 10.5–63 μg/ml for Tinidazole and Furazolidone resp.     

A Novel Spectrophotometric Method for the Determination of Zolmitriptan in Pharmaceutical Formulations

A simple, rapid, cost effective and extraction‐free spectrophotometric method has been developed for the determination of zolmitriptan in pharmaceutical raw and dosage forms. The method is based on the charge‐transfer reaction of zolmitriptan in acetonitrile medium with 0.2% 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone to form a colored product peaking at 555 nm. Beer's law is obeyed in the concentration range 10‐250 μg mL^?1 with molar absorptivity of 1.7 × 10³ L mole^?1 cm^?1. The effects of variables such as reagent concentration, time of reaction, color stability and interferences have been investigated to optimize the procedure. The results have been validated analytically and statistically. The proposed method has been successfully applied for the determination of zolmitriptan in pharmaceutical formulations. Results indicate that the method is accurate, precise and reproducible (relative standard deviation < 2%).     

Simultaneous Estimation of Cinnamaldehyde and Eugenol in Essential Oils and Traditional and Ultrasound-Assisted Extracts of Different Species of Cinnamon Using a Sustainable/Green HPTLC Technique

A wide range of analytical techniques are reported for the determination of cinnamaldehyde (CCHO) and eugenol (EOH) in plant extracts and herbal formulations either alone or in combination. Nevertheless, sustainable/green analytical techniques for the estimation of CCHO and EOH either alone or in combination are scarce in the literature. Accordingly, the present research was carried out to establish a rapid, highly sensitive, and sustainable high-performance thin-layer chromatography (HPTLC) technique for the simultaneous estimation of CCHO and EOH in the traditional and ultrasound-assisted methanolic extracts of Cinnamomum zeylanicum, C. burmannii, and C. cassia and their essential oils. The simultaneous estimation of CCHO and EOH was performed through NP-18 silica gel 60 F254S HPTLC plates. The cyclohexane/ethyl acetate (90:10, v v⁻¹) solvent system was optimized as the mobile phase for the simultaneous estimation of CCHO and EOH. The greenness score of the HPTLC technique was predicted using AGREE software. The entire analysis was carried out at a detection wavelength of 296 nm for CCHO and EOH. The sustainable HPTLC technique was observed as linear in the range 10–2000 ng band⁻¹ for CCHO and EOH. The proposed technique was found to be highly sensitive, rapid, accurate, precise, and robust for the simultaneous estimation of CCHO and EOH. The content of CCHO in traditional methanolic extracts of C. zeylanicum, C. burmannii, and C. cassia was found to be 96.36, 118.49, and 114.18 mg g⁻¹, respectively. However, the content of CCHO in ultrasound-assisted methanolic extracts of C. zeylanicum, C. burmannii, and C. cassia was found to be 111.57, 134.39, and 129.07 mg g⁻¹, respectively. The content of CCHO in essential oils of C. zeylanicum, C. burmannii, and C. cassia was found to be 191.20, 214.24, and 202.09 mg g⁻¹, respectively. The content of EOH in traditional methanolic extracts of C. zeylanicum, C. burmannii, and C. cassia was found to be 73.38, 165.41, and 109.10 mg g⁻¹, respectively. However, the content of EOH in ultrasound-assisted methanolic extracts of C. zeylanicum, C. burmannii, and C. cassia was found to be 87.20, 218.09, and 121.85 mg g⁻¹, respectively. The content of EOH in essential oils of C. zeylanicum, C. burmannii, and C. cassia was found to be 61.26, 79.21, and 69.02 mg g⁻¹, respectively. The amounts of CCHO and EOH were found to be significantly higher in ultrasound-assisted extracts of all species compared to its traditional extraction and hence ultrasound extraction has been proposed as a superior technique for the extraction of CCHO and EOH. The AGREE analytical score of the present analytical technique was predicted as 0.75, suggesting excellent greenness profile of the proposed analytical technique. Based on all these observations and results, the proposed sustainable HPTLC technique can be successfully used for the simultaneous estimation of CCHO and EOH in different plant extracts and herbal products.     

High-Performance Liquid Chromatographic Method for the Simultaneous Determination of Four Flavonols in Food Supplements and Pharmaceutical Formulations

A method using high-performance liquid chromatography with diode array detection (HPLC-DAD) as a powerful separation technique has been developed for the simultaneous determination of the four flavonols rutin, quercetin, kaempferol and isorhamnetin in food supplements and pharmaceutical formulations. The chromatographic separation was achieved in 36?min using a Symmetry C₁₈ column (250?×?3?mm; 5?µm) as the stationary phase and a mixture of methanol, acetonitrile, and pH 2.5 aqueous acetic acid as the mobile phase in gradient elution mode. The analytical wavelengths were 256?nm for rutin, quercetin and isorhamnetin, and 368?nm for kaempferol. An ultrasound-assisted extraction protocol was performed using methanol as solvent. The detection and quantification limits were lower than 0.03?µg mL^?1 and 0.08?µg mL^?1, respectively. The inter-day and intra-day precisions were less than 4.8 and 5.1%, respectively, and the average recoveries were in the range from 96 to 107%. The method was applied for the determination of the studied flavonols in food supplements and pharmaceutical preparations. The satisfactory recovery values demonstrate the potential of the developed method for the determination of the analytes in these samples. In addition, the method is suitable for routine quality control due its ease of operation.     

Simultaneous Determination of Copper (II) and Mercury (II) by Using a Zero-Crossing Method

Abstract

The application of a zero-crossing method to the simultaneous determination of copper (II) and mercury (II) with methylethylenediaminetetraacetic acid (MEDTA) is described. The procedure does not require equations to be solved, and it is suitable for concentrations of 0.008–0.036 mg ml^?1 of copper and 0.025–0.300 mg ml^?1 of mercury. The main interferences, both anionic and cationic, were easily eliminated. The method was applied to different aqueous matrices. It was compared with an atomic absorption spectrophotometry method (AA) and good results were obtained.     

Simultaneous Differential Pulse Voltammetric Determination of Ascorbic Acid and Caffeine in Pharmaceutical Formulations Using a Boron‐Doped Diamond Electrode

A cathodically pretreated boron‐doped diamond electrode was used for the simultaneous anodic determination of ascorbic acid (AA) and caffeine (CAF) by differential pulse voltammetry. Linear calibration curves (r=0.999) were obtained from 1.9×10^?5 to 2.1×10^?4 mol L^?1 for AA and from 9.7×10^?6 to 1.1×10^?4 mol L^?1 for CAF, with detection limits of 19 μmol L^?1 and 7.0 μmol L^?1, respectively. This method was successfully applied for the determination of AA and CAF in pharmaceutical formulations, with results equal to those obtained using a HPLC reference method.     

Determination of Cinnarizine in Pure and Pharmaceutical Formulations

Two simple, rapid and sensitive extractive spectrophotometric methods have been developed for the assay of cinnarizine (CNR) in pure and pharmaceutical formulations. The methods are based on the formation of chloroform soluble ion‐association complexes of CNR with thymol blue (TB) and with cresol red (CR) inNaOAc‐AcOH buffer of pH 3.6 for TB and in KCl‐HCl buffer of pH 1.6 for CR with absorption maxima at 405 nm and at 403 nm for TB and CR, respectively. Reaction conditions were optimized to obtain the maximum color intensity. The systems obeyed Beer's law in the range of 0.6–15.8 and 0.8–16.6 μg mL^?1 for TB and CR, respectively. Various analytical parameters have been evaluated and the results have been validated by statistical data.     

小波神经网络用于钼和钨的同时测定

介绍了小波神经网络的结构和算法，并首次用于混合试样中的钼和钨含量测定，在小波神经网络中，采用Ｍｏｒｌｅｔ母小波和一维搜索变步长共轭梯度优化方法，结果表明，小波神经网络优于ＢＰ网络，其预测含量的回收率在９６．０％～１０４．６％之间。     

Simultaneous Spectrophotometric Determination of Aspirin,Paracetamol, Caffeine,and Chlorphenamine from Pharmaceutical Formulations Using Multivariate Regression Methods

This paper presents a simultaneous spectrophotometric determination of aspirin, paracetamol, caffeine, and chlorphenamine from commercial pharmaceutical products using principal component regression and partial-least squares regression. The concentration of the training set was established employing a partial factorial calibration design at four levels. Several quality parameters and recovery values obtained on authentic samples illustrated excellent performance characteristics concerning the goodness of fit and the accuracy and precision of prediction. Eight pharmaceutical formulations containing at least two of these four mentioned active ingredients and diverse electuaries were successfully analyzed. The obtained results were also validated by high-performance liquid chromatography.     

Simultaneous Square‐Wave Voltammetric Determination of Paracetamol,Caffeine and Orphenadrine in Pharmaceutical Formulations Using a Cathodically Pretreated Boron‐Doped Diamond Electrode

An electroanalytical method for the simultaneous determination of paracetamol (PAR), caffeine (CAF), and orphenadrine (ORPH) using the square‐wave voltammetry (SWV) and a cathodically pretreated boron‐doped diamond electrode was developed. The method exhibits linear responses to PAR, CAF, and ORPH in the concentration ranges 5.4×10^?7–6.1×10^?5 M, 7.8×10^?7–3.5×10^?5 M, and 7.8×10^?7–3.5×10^?5 M, respectively, with detection limits of 2.3×10^?7 M, 9.6×10^?8 M, and 8.4×10^?8 M, respectively. The proposed method was successfully applied in the simultaneous determination of these analytes in pharmaceutical formulations.     

Simultaneous HPTLC Determination of Clotrimazole and Tinidazole in a Pharmaceutical Formulation

JPC – Journal of Planar Chromatography – Modern TLC - An HPTLC method for simultaneous determination of clotrimazole and tinidazole in a pharmaceutical formulation has been developed...     

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 Spectrophotometric Determination of Benzyl Alcohol and Diclofenac in Pharmaceutical Formulations by Chemometrics Method

Diclofenac sodium (DS) is a drug with analgesic, antipyretic, and anti‐inflammatory properties. It is present in numerous pharmaceutical preparations. In injectable forms, it is usually accompanied by benzyl alcohol (BA) as an excipient, which is used as a blocking anesthetic (4%) and an antiseptic (4–10%). In this work a spectrophotometric methodology was applied in order to determine benzyl alcohol and diclofenac in injectable formulations by applying a multivariate calibration method. By a multivariate calibration method such as partial least squares (PLS), it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. In this study, the concentration model is based on absorption spectra in the 230–320 nm range for 25 different mixtures of benzyl alcohol and diclofenac. Calibration matrix contains 10–95 and 1–50 μg mL^?1 for benzyl alcohol and diclofenac, respectively. The root mean square errors of prediction (RMSEP) for benzyl alcohol and diclofenac were 3.0776 and 1.7557, respectively. The proposed method was validated by using a set of synthetic sample mixtures and subsequently applied to simultaneous determination of benzyl alcohol and diclofenac in two different pharmaceutical formulations.     

Simultaneous Determination of Estrogen and Progesterone Receptors Using Human Uterus as a Standard

Abstract

Numerous reports have shown a high degree of correlation between the presence of estrogen and progesterone receptors in cancerous breast tumors and response to endocrine therapy. There are several methods in use for measurement of these receptors, but all are time consuming and require large amounts of tumor tissue. Our laboratory needed a faster and simpler method to determine receptor concentration. We describe here an assay which utilizes human uterus extract with known receptor concentration as a standard to determine receptor concentration of tumor tissues. This method is simple, fast and will allow determination of estrogen and progesterone receptor in up to ten patient samples at one time.     

Determination and Quantification of Pitavastatin Calcium in Tablet Dosage Formulation by HPTLC Method

Abstract

A simple, sensitive, reliable, and rapid HPTLC method has been developed for the determination of pitavastatin calcium in tablet dosage form. Identification and determination were performed on aluminum backed silica gel 60F₂₅₄ washed with methanol. The mobile phase of ethyl acetate‐methanol‐ammonia‐1 drop formic acid (7:2:0.8) calibration plots were established showing the dependence of response (peak area) on the amount chromatographed. The spot were scanned at 245 nm. The method has a linear range of 50–250 ng/spot. The method was validated for selectivity, repeatability, and accuracy. The method was used for determination of the compound in commercial pharmaceutical dosage forms. It is a more effective option than other chromatographic techniques in routine quality control.     

Photometric Determination of Iron in Pharmaceutical Formulations Using Double-Beam Direct Injection Flow Detector

In this work, an innovative, flow-through, double-beam, photometric detector with direct injection of the reagents (double-DID) was used for the first time for the determination of iron in pharmaceuticals. For stable measurement of the absorbance, double paired emission-detection LED diodes and a log ratio precision amplifier have been applied. The detector was integrated with the system of solenoid micro-pumps. The micro-pumps helped to reduce the number of reagents used and are responsible for precise solution dispensing and propelling. The flow system is characterized by a high level of automation. The total iron was determined as a Fe(II) with photometric detection using 1,10-phenanthroline as a complexing agent. The optimum conditions of the propose analytical procedure were established and the method was validated. The calibration graph was linear in the range of 1 to 30 mg L⁻¹. The limit of detection (LOD) was 0.5 mg L⁻¹. The throughput of the method was 90 samples/hour. The repeatability of the method expressed as the relative standard deviation (R.S.D.) was 2% (n = 10). The method was characterized by very low consumption of reagents and samples (20 μL each) and a small amount of waste produced (about 540 µL per analysis). The proposed flow method was successfully applied for determination of iron in pharmaceutical products. The results were in good agreement with those obtained using the manual UV-Vis spectrophotometry and with values claimed by the manufacturers. The flow system worked very stably and was insensitive to bubbles appearing in the system.