scholarly journals Spectrophotometric determination of methyldopa in pharmaceutical formulations

2005 ◽  
Vol 30 (3) ◽  
pp. 23-28 ◽  
Author(s):  
P. R. S. Ribeiro ◽  
L. Pezza ◽  
H. R. Pezza
Keyword(s):  
Correlation Coefficient ◽  
Spectrophotometric Method ◽  
Confidence Level ◽  
Low Cost ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Pharmaceutical Products ◽  
Complexation Reaction ◽  
Excellent Correlation

A new, simple, precise, rapid and low-cost spectrophotometric method for methyldopa determination in pharmaceutical preparations is described. This method is based on the complexation reaction of methyldopa with molybdate. Absorbance of the resulting yellow coloured product is measured at 410 nm. Beer's Law is obeyed in a concentration range of 50 - 200 µg ml-1 methyldopa with an excellent correlation coefficient (r = 0.9999). No interference was observed from common excipients in formulations. The results show a simple, accurate, fast and readily applied method to the determination of methyldopa in pharmaceutical products. The analytical results obtained for these products by the proposed method are in agreement with those of the Brazilian Pharmacopoeia procedure at 95% confidence level.

scholarly journals Spectrophotometric Determination ofN-Acetyl-L-Cysteine andN-(2-Mercaptopropionyl)-Glycine in Pharmaceutical Preparations

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Lea Kukoc-Modun ◽  
Njegomir Radić
Keyword(s):  
Regression Analysis ◽  
Detection Limit ◽  
Correlation Coefficient ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Pharmaceutical Preparations ◽  
Complexation Reaction ◽  
Calibration Data ◽  
Pharmaceutical Excipients

A simple spectrophotometric method for the determination ofN-acetyl-L-cysteine (NAC) andN-(2-mercaptopropionyl)glycine (MPG) in pharmaceutical preparations was developed, validated, and used. The proposed equilibrium method is based on a coupled two-step redox and complexation reaction. In the first step, Fe(III) is reduced to Fe(II) by NAC or MPG. Subsequently, Fe(II) is complexed with 2,4,6-tripyridyl-s-triazine (TPTZ). Several analytical parameters of the method were optimized for NAC and MPG analysis in the concentration range from 1.0 μM to 100.0 μM. Regression analysis of the calibration data showed a good correlation coefficient (0.9999). The detection limit of the method was 0.14 μM for NAC and 0.13 μM for MPG. The method was successfully applied to quantify NAC and MPG in pharmaceutical preparations. No interferences were observed from common pharmaceutical excipients.

scholarly journals A simple spectrophotometric method for the determination of captopril in pharmaceutical preparations using ammonium molybdate

2010 ◽  
Vol 35 (3) ◽  
pp. 179-188 ◽  
Author(s):  
P. R. S Ribeiro ◽  
L Pezza ◽  
H. R Pezza
Keyword(s):  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Reduction Reaction ◽  
Ammonium Molybdate ◽  
Excellent Correlation ◽  
Limit Of Quantification ◽  
The Common

A simple, rapid and sensitive spectrophotometric method for the determination of captopril (CPT) in pharmaceutical formulations is proposed. This method is based on the reduction reaction of ammonium molybdate, in the presence of sulphuric acid, for the group thiol of CPT, producing a green compound (λ max 407 nm). Beer's law is obeyed in a concentration range of 4.60 x 10-4 - 1.84 x 10-3 mol l-1 of CPT with an excellent correlation coefficient (r = 0.9995). The limit of detection and limit of quantification were 7.31 x 10-6 e 2.43 x 10-5 mol l-1 of CPT, respectively. The proposed method was successfully applied to the determination of CPT in commercial brands of pharmaceuticals. No interferences were observed from the common excipients in the formulations. The results obtained by the proposed method were favorably compared with those given by the official reported method at 95 % confidence level.

scholarly journals A SIMPLE SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF CAPTOPRIL IN PHARMACEUTICAL PREPARATIONS USING AMMONIUM MOLYBDATE

2018 ◽  
Vol 35 (3) ◽  
pp. 179
Author(s):  
Paulo Roberto Da Silva Ribeiro ◽  
Leonardo Pezza ◽  
Helena Redigolo Pezza
Keyword(s):  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Reduction Reaction ◽  
Ammonium Molybdate ◽  
Excellent Correlation ◽  
Limit Of Quantification ◽  
The Common

A simple, rapid and sensitive spectrophotometric method for the determination of captopril (CPT) in pharmaceutical formulations is proposed. This method is based on the reduction reaction of ammonium molybdate, in the presence of sulphuric acid, for the group thiol of CPT, producing a green compound (λmax 407 nm). Beer’s law is obeyed in a concentration range of 4.60 x 10-4 – 1.84 x 10-3 mol l-1 of CPT with an excellent correlation coefficient (r = 0.9995). The limit of detection and limit of quantification were 7.31 x 10-6 e 2.43 x 10-5 mol l-1 of CPT, respectively. The proposed method was successfully applied to the determinationof CPT in commercial brands of pharmaceuticals. No interferences were observed from the common excipients in the formulations. The results obtained by the proposed method were favorably compared with those given by the official reported method at 95 % confidence level.

scholarly journals Spectrophotometric determination of Valsartan in pure form and in its pharmaceutical preparations

2021 ◽  
Vol 26 (4) ◽  
Author(s):  
Qabas Rashid ◽  
Ruwaida Farman Salih
Keyword(s):  
Correlation Coefficient ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Pure Form ◽  
Chromogenic Reagent

An easy, rapid and economical spectrophotometric method for  determination of  Valsartan (Val), by reaction with 4-chloro-7-nitrobenzofurazan (NBD-Cl) as reagent in an alkaline interemediate. This method is based on the forming of product between (Val) and the chromogenic reagent (NBD-Cl), to produce a brown color at (pH 11.9) and λmax. 470 nm.  Beer’s Law is obeyed at the concentrations range of (0.4-14.8 µg/ml), with molar absorptivity of (1.05×104 L/mol.cm) and correlation coefficient 0.9827, The limit of detection was 0.557 µg/ml. The suggested method was prosperity implement to the determination of (Val) in  pure form and in its pharmaceutical formulations (tablets).

Development and Validation of an Eco-Friendly and Low-Cost Method for the Quantification of Cefepime Hydrochloride in Powder for Injectable Solution Using Infrared (IR) Spectroscopy

2020 ◽  
Vol 16 (4) ◽  
pp. 456-464
Author(s):  
Danilo F. Rodrigues ◽  
Hérida R.N. Salgado
Keyword(s):  
Ir Spectroscopy ◽  
Low Cost ◽  
Pharmaceutical Preparations ◽  
Potassium Bromide ◽  
Pharmaceutical Products ◽  
Injectable Formulation ◽  
Ich Guidelines ◽  
Lactam Ring ◽  
Development And Validation

Background: A simple, eco-friendly and low-cost Infrared (IR) method was developed and validated for the analysis of Cefepime Hydrochloride (CEF) in injectable formulation. Different from some other methods, which employ organic solvents in the analyses, this technique does not use these types of solvents, removing large impacts on the environment and risks to operators. Objective: This study aimed at developing and validating a green analytical method using IR spectroscopy for the determination of CEF in pharmaceutical preparations. Methods: The method was validated according to ICH guidelines and the quantification of CEF was performed in the spectral region absorbed at 1815-1745 cm-1 (stretching of the carbonyl group of β- lactam ring). Results: The validated method showed to be linear (r = 0.9999) in the range of 0.2 to 0.6 mg/pellet of potassium bromide, as well as for the parameters of selectivity, precision, accuracy, robustness and Limits of Detection (LOD) and Quantification (LOQ), being able to quantify the CEF in pharmaceutical preparations. The CEF content obtained by the IR method was 103.86%. Conclusion: Thus, the method developed may be an alternative in the quality control of CEF sample in lyophilized powder for injectable solution, as it presented important characteristics in the determination of the pharmaceutical products, with low analysis time and a decrease in the generation of toxic wastes to the environment.

scholarly journals Development and application of a portable instrument for drugs analysis in pharmaceutical preparations

2015 ◽  
Vol 51 (3) ◽  
pp. 699-708
Author(s):  
Paulo Roberto da Silva Ribeiro ◽  
Helena Redigolo Pezza ◽  
Leonardo Pezza ◽  
Liliane Spazzapam Lima ◽  
Matthieu Tubino
Keyword(s):  
Low Cost ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Products ◽  
Ammonium Molybdate ◽  
Quantitative Studies ◽  
Significant Difference ◽  
Drugs Analysis ◽  
And Performance

This article describes the application and performance of an inexpensive, simple and portable device for colorimetric quantitative determination of drugs in pharmaceutical preparations. The sensor is a light detector resistor (LDR) incorporated into a black PTFE cell and coupled to a low-cost multimeter (Ohmmeter). Quantitative studies were performed with captopril/p-chloranil/H2O2 and methyldopa/ammonium molybdate systems. Calibration curves were obtained by plotting the electrical resistance of the LDR against the concentration of the colored species in the ranges 1.84 × 10-4 to 1.29 × 10-3mol L-1 and 5.04 × 10-4 to 2.52 × 10-3 mol L-1 for captopril/p-chloranil/H2O2 and methyldopa/ammonium molybdate systems, respectively, exhibiting good coefficients of determination. Statistical analysis of the results obtained showed no significant difference between the proposed methodologies and the official reported methods, as evidenced by the t-test and variance ratio at a 95% confidence level. The results of this study demonstrate the applicability of the instrument for simple, accurate, precise, fast,in situ and low-cost colorimetric analysis of drugs in pharmaceutical products.

scholarly journals Development and validation of a simple spectrophotometric method for the determination of methyldopa in both bulk and marketed dosage formulations

2014 ◽  
Vol 50 (3) ◽  
pp. 573-582 ◽  
Author(s):  
Paulo Roberto da Silva Ribeiro ◽  
Reginária Morais Duarte
Keyword(s):  
Sodium Nitrite ◽  
Spectrophotometric Method ◽  
Confidence Level ◽  
Absorption Maximum ◽  
Pharmaceutical Preparations ◽  
Coefficient Of Determination ◽  
Colored Product ◽  
Development And Validation ◽  
Nitrosation Reaction

A simple, precise, sensitive, rapid, specific and economical spectrophotometric method was developed to determine methyldopa (MTD) content in bulk and pharmaceutical dosage formulations. The proposed method was based on the formation of a colored product from the nitrosation reaction of MTD with sodium nitrite in an acid medium. The resultant nitroso derivative species reacts further with sodium hydroxide and is converted it into a more stable compound. This yellow nitrosation product exhibited an absorption maximum at 430 nm. Beer's Law was obeyed in a concentration range of 6.37 to 82.81 μg mL-1 MTD with an excellent coefficient of determination (R2 = 0.9998). No interference was observed from common excipients in formulations. The results showed the method to be simple, accurate and readily applied for the determination of MTD in pure form and in pharmaceutical preparations. The analytical results obtained for these products using the proposed method are in agreement with those of the Brazilian Pharmacopoeia procedure at a 95% confidence level.

scholarly journals Potentiometric determination of captopril in pharmaceutical formulations

2003 ◽  
Vol 28 (1) ◽  
pp. 39-44 ◽  
Author(s):  
P. R. da S. Ribeiro ◽  
A. O. Santini ◽  
H. R. Pezza ◽  
L. Pezza
Keyword(s):  
Low Cost ◽  
Standard Procedure ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Magnesium Stearate ◽  
The United States ◽  
United States Pharmacopoeia ◽  
Glass Ph Electrode ◽  
Tablet Dosage

A simple, precise, rapid and low-cost potentiometric method for captopril determination in pure form and in pharmaceutical preparations is proposed. Captopril present in tablets containing known quantity of drug was potentiometrically titrated in aqueous solution with NaOH using a glass pH electrode, coupled to an autotitrator. No interferences were observed in the presence of common components of the tablets as lactose, microcrystalline cellulose, croscarmellose sodium, starch and magnesium stearate. The analytical results obtained by applying the proposed method compared very favorably with those obtained by the United States Pharmacopoeia Standard procedure. Recovery of captopril from various tablet dosage formulations range from 98.0 to 102.0%.

scholarly journals A Sensitive UV Spectrophotometric Method for the Determination of Gabapentin

2009 ◽  
Vol 6 (s1) ◽  
pp. S163-S170 ◽  
Author(s):  
R. Singh Gujral ◽  
S. Manirul Haque ◽  
P. Shanker
Keyword(s):  
Spectrophotometric Method ◽  
Good Accuracy ◽  
Limit Of Detection ◽  
Low Cost ◽  
Pharmaceutical Formulations ◽  
Accuracy And Precision ◽  
Ich Guidelines ◽  
Limit Of Quantitation ◽  
Precision Limit

An accurate and validated spectrophotometric method was developed for the determination of gabapentin. This is simple, sensitive and low cost UV spectrophotometric method. The method is based on the direct measurement of the native absorbance of the drug. The detection was done at 210 nm. The method was linear in the range of 0.25 - 3.5 µ g/mL with correlation coefficient of 0.9999. It is validated according to the ICH guidelines with respect to linearity, selectivity, accuracy and precision, limit of quantitation and limit of detection. The method has been applied to assess gabapentin in pharmaceutical formulations with good accuracy and precision and relatively free of interference from coexisting substances.

scholarly journals Application of Thin-Layer Chromatography in Combination with Densitometry for the Determination of Diclofenac in Enteric Coated Tablets

2019 ◽  
Vol 12 (4) ◽  
pp. 183 ◽  
Author(s):  
Wioletta Parys ◽  
Alina Pyka-Pająk ◽  
Małgorzata Dołowy
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Degradation Products ◽  
Low Cost ◽  
Diclofenac Sodium ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Products ◽  
Enteric Coated ◽  
Layer Chromatography

Diclofenac belongs to the drug class non-steroidal anti-inflammatory drugs widely used in Europe as well as all over the world. Thus, it is important to conduct research on its quality control of available pharmaceutical preparations like for example enteric coated tablets. Among various analytical techniques, thin-layer chromatography (TLC) is ideal for this task due to their short time analysis, ease of operation and low cost. Hence, the aim of this study was to develop the optimal conditions of analysis and quantitative determination of diclofenac sodium in enteric tablets by using TLC in combination with densitometry. Of all chromatographic systems tested, the best is the one which consists of silica gel 60F254 and cyclohexane: chloroform:methanol:glacial acetic acid (6:3:0.5:0.5 v/v) as the mobile phase, which allows the successful separation of examined diclofenac sodium as active component and the largest number (twelve) of its degradation products as potential impurities of its pharmaceutical products. This indicates that the newly developed method is more effective than previously reported assays by Starek and Krzek. Linearity range was found to be 4.00–18.00 μg/spot for diclofenac sodium. The results of the assay of enteric tablet formulations equals 98.8% of diclofenac sodium in relation to label claim is in a good agreement with pharmaceutical requirements.

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