scholarly journals Sensitive and Selective Spectrophotometric Determination of Gabapentin in Capsules Using Two Nitrophenols as Chromogenic Agents

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Sameer A. M. Abdulrahman ◽  
Kanakapura Basavaiah
Keyword(s):  
Picric Acid ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Lewis Base ◽  
Pure Form ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Significant Difference

Two simple and selective spectrophotometric methods have been proposed for the determination of gabapentin (GBP) in pure form and in capsules. Both methods are based on the proton transfer from the Lewis acid such as 2,4,6-trinitrophenol (picric acid; PA) or 2,4-dinitrophenol (2,4-DNP) to the primary amino group of GBP which works as Lewis base and formation of yellow ion-pair complexes. The ion-pair complexes formed show absorption maximum at 415 and 420 nm for PA and 2,4-DNP, respectively. Under the optimized experimental conditions, Beer's law is obeyed over the concentration ranges of 1.25–15.0 and 2.0–18.0 μg mL−1GBP for PA and 2,4-DNP methods, respectively. The molar absorptivity, Sandell's sensitivity, detection and, quantification limits for both methods are also reported. The proposed methods were applied successfully to the determination of GBP in pure form and commercial capsules. Statistical comparison of the results was performed using Student'st-test and F-ratio at 95% confidence level, and there was no significant difference between the reference and proposed methods with regard to accuracy and precision. Further, the validity of the proposed methods was confirmed by recovery studies via standard addition technique.

scholarly journals Cerimetric determination of simvastatin in pharmaceuticals based on redox and complex formation reactions

2018 ◽  
Vol 33 (2) ◽  
pp. 21
Author(s):  
Kanakapura Basavaiah ◽  
Okram Zenita Devi
Keyword(s):  
Limit Of Detection ◽  
Reference Method ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Fixed Quantity ◽  
Bulk Drug ◽  
Student’S T

Two sensitive spectrophotometric methods are described for the determination of simvastatin (SMT) in bulk drug and in tablets. The methods are based on the oxidation of SMT by a measured excess of cerium (IV) in acid medium followed by determination of unreacted oxidant by two different reaction schemes. In one procedure (method A), the residual cerium (IV) is reacted with a fixed concentration of ferroin and the increase in absorbance is measured at 510 nm. The second approach (method B) involves thereduction of the unreacted cerium (IV) with a fixed quantity of iron (II), and the resulting iron (III) is complexed with thiocyanate and the absorbance measured at 470 nm. In both methods, the amount of cerium (IV) reacted corresponds to SMT concentration. The experimental conditions for both methods were optimized. In method A, the absorbance is found to increase linearly with SMT concentration (r = 0.9995) whereas in method B, the same decreased (r = -0.9943). The systems obey Beer’s law for 0.6-7.5 and 0.5-5.0 μg mL-1 for method A and method B, respectively. The calculated molar absorptivity values are 2.7 X 104 and 1.06 X 105 Lmol-1 cm-1, respectively; and the corresponding sandel sensitivity values are 0.0153 and 0.0039μg cm-2, respectively. The limit of detection (LOD) and quantification (LOQ) are reported for both methods. Intra-day and inter-day precision, and accuracy of the methods were established as per the current ICH guidelines. The methods were successfully applied to the determination of SMT in tablets and the results were statistically compared with those of the reference method by applying the Student’s t-test and F-test. No interference was observed from the common excipients added to tablets. The accuracy and validity of the methods were further ascertained by performing recovery experiments via standard addition procedure.

scholarly journals SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF SOFOSBUVIR AND DACLATASVIR IN PURE AND DOSAGE FORMS

2021 ◽  
pp. 112-119
Author(s):  
MONIR Z. SAAD ◽  
ATEF AMER ◽  
KHALED ELGENDY ◽  
BASEM ELGENDY
Keyword(s):  
Indigo Carmine ◽  
Reference Method ◽  
Standard Addition ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Experimental Conditions ◽  
Fixed Amount ◽  
Alizarin Red ◽  
Spectrophotometric Methods

Objective: Two simple, sensitive and accurate spectrophotometric methods have been developed for the determination of sofosbuvir (SOF) and daclatasvir (DAC) in pure forms and pharmaceutical formulations. Methods: The proposed methods are based on the oxidation of SOF and DAC by a known excess of cerium(IV) ammonium nitrate in sulphuric acid medium followed by determination of unreacted cerium(IV) by adding a fixed amount of indigo carmine (IC) and alizarin red S (ARS) dyes followed by measuring the absorbance at 610 and 360 nm, respectively. The experimental conditions affecting the reaction were studied and optimized. Results: The beer’s law was obeyed in the concentration ranges of 0.2-3.0, 0.2-4.0 for SOF and 0.5-4.5 and 0.5-5.0 μg/ml for DAC using IC and ARS methods, respectively with a correlation coefficient ≥ 0.9991. The calculated molar absorptivity values are 2.354 × 104, 1.933 × 104 for SOF and 1.786 × 104 and 2.015 × 104 L/mol. cm for DAC using IC and ARS methods, respectively u. The limits of detection and quantification are also reported. Intra-day and inter-day precision and accuracy of the methods have been evaluated. Conclusion: The methods were successfully applied to the assay of SOF and DAC in tablets and the results were statistically compared with those of the reference method by applying Student’s t-test and F-test. No interference was observed from the common tablet excipients. The accuracy and reliability of the methods were further ascertained by performing recovery studies using the standard addition method.

scholarly journals Indirect spectrophotometric determination of diltiazem hydrochloride in pure form and pharmaceutical formulations

2005 ◽  
Vol 3 (3) ◽  
pp. 520-536 ◽  
Author(s):  
Akram El-Didamony
Keyword(s):  
Reference Method ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Pure Form ◽  
Diltiazem Hydrochloride ◽  
Spectrophotometric Methods ◽  
Chromotrope 2R ◽  
Significant Difference ◽  
Comparison Of The Results

AbstractThree simple, accurate, and sensitive spectrophotometric methods (A, B and C) have been described for the indirect assay of diltiazem hydrochloride (DIL.HCl), either in pure form or in pharmaceutical formulations. The first method (A) is based on the oxidation of DIL.HCl by N-bromosuccinimide (NBS) and determination of unconsumed NBS by measuring the decrease in absorbance of amaranth dye (AM) at a suitable λmax=521 nm. Other methods (B) and (C) involve the addition of excess cerric ammonium sulfate (CAS) and subsequent determination of the unconsumed oxidant by a decrease in the red color of chromotrope 2R (C2R) at a suitable λmax=528 nm or a decrease in the orange-pink color of rhodamine 6G (Rh6G) at λmax=525 nm, respectively. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 3.0–9.0, 3.5–7.0 and 3.5–6.3 μg ml−1 for methods A, B and C, respectively. The apparent molar absorptivity, Sandell's sensitivity, detection and quantification limits were calculated. The proposed methods have been applied successfully for the analysis of the drug in its pure form and its dosage form. No interference was observed from a common pharmaceutical adjuvant. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.

scholarly journals Simple and rapid spectrophotometric assay of albendazole in pharmaceuticals using iodine and picric acid as CT complexing agents

2014 ◽  
Vol 50 (4) ◽  
pp. 839-850 ◽  
Author(s):  
Nagaraju Swamy ◽  
Kanakapura Basavaiah
Keyword(s):  
Picric Acid ◽  
Molar Absorptivity ◽  
Complexing Agents ◽  
Complexation Reaction ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Bulk Drug ◽  
Ct Complexes ◽  
Acceptor Method

Two simple, rapid and inexpensive spectrophotometric methods are described for the determination of albendazole (ALB) in bulk drug and in tablets. The methods are based on charge-transfer (CT) complexation reaction involving ALB as n-donor and iodine as σ-acceptor (method A) in dichloromethane or picric acid (PA) as π-acceptor (method B) in chloroform. The absorbance of CT complexes was measured at 380 nm for method A, and 415 nm for method B. The optimization of the experimental conditions is described. Under optimum conditions, Beer's law obeyed over the concentration ranges 8.0-240 and 2.4-42 μg mL-1 for method A and method B, respectively. The apparent molar absorptivity of CT complexes at the respective λmax are calculated to be 1.17×103 and 5.22×103 L mol-1cm-1 respectively, and the corresponding Sandell sensitivity values are 0.2273 and 0.0509 ng cm-2. The limits of detection (LOD) and quantification (LOQ) are calculated to be (0.69 and 2.08), and (0.10 and 0.30) μg mL-1 with method A, and method B, respectively. The intra-day and inter-day accuracy expressed as % RE and precision expressed as % RSD were less than 3%. The methods were applied to the determination of ALB in tablets.

scholarly journals Titrimetric and Spectrophotometric Assay of Oxcarbazepine in Pharmaceuticals Using N-Bromosuccinimide and Bromopyrogallol Red

2011 ◽  
Vol 2011 ◽  
pp. 1-8
Author(s):  
Nagaraju Rajendraprasad ◽  
Kanakapura Basavaiah ◽  
Kanakapura B. Vinay
Keyword(s):  
Spectrophotometric Method ◽  
Reference Method ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Spectrophotometric Methods ◽  
Bromopyrogallol Red ◽  
Accuracy And Precision ◽  
Significant Difference ◽  
Comparison Of The Results

Titrimetric and spectrophotometric methods are described for the determination of oxcarbazepine (OXC) in bulk drug and in tablets. The methods use N-bromosuccinimide (NBS) and bromopyrogallol red (BPR) as reagents. In titrimetry (method A), an acidified solution of OXC is titrated directly with NBS using methyl orange as indicator. Spectrophotometry (method B) involves the addition of known excess of NBS to an acidified solution of OXC followed by the determination of the unreacted NBS by reacting with BPR and measuring the absorbance of the unreacted dye at 460 nm. Titrimetry allows the determination of 6–18 mg of OXC and follows a reaction stoichiometry of 1 : 1 (OXC : NBS), whereas spectrophotometry is applicable over the concentration range of 0.8–8.0 μg mL-1. Method B with a calculated molar absorptivity of2.52×104 L mol-1 cm-1is the most sensitive spectrophotometric method ever developed for OXC. The optical characteristics such as limits of detection (LOD), quantification (LOQ), and Sandell's sensitivity values are also reported for the spectrophotometric method. The accuracy and precision of the methods were studied on intraday and interday basis. The methods described could usefully be applied to routine quality control of tablets containing OXC. No interference was observed from common pharmaceutical adjuvants. Statistical comparison of the results with a reference method shows an excellent agreement and indicates no significant difference in accuracy and precision. The reliability of the methods was further ascertained by recovery studies in standard addition procedure.

scholarly journals Use of Alizarin Red S as an Ion-Pair Reagent for the Spectrophotometric Assay of Fexofenadine in Pharmaceuticals and in Spiked Human Urine

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Madihalli S. Raghu ◽  
Kanakapura Basavaiah ◽  
Kudige N. Prashanth ◽  
Kankapura B. Vinay
Keyword(s):  
Human Urine ◽  
Standard Addition ◽  
Cost Effective ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Alizarin Red S ◽  
Alizarin Red ◽  
Spectrophotometric Methods ◽  
Spiked Human Urine

The present study describes two simple, rapid, selective, and cost-effective spectrophotometric methods for the determination of an antiallergic drug, fexofenadine hydrochloride (FFH), in bulk drug, tablets, and in spiked human urine. The first method (method A) is based on the formation of yellow-colored ion-pair complex between FFH and alizarin red S (AZS) in acid medium which was extracted into dichloromethane, and the absorbance was measured at 440 nm. The second method (method B) is based on the breaking of the yellow FFH–AZS ion-pair complex in alkaline medium followed by the measurement of the violet-colored free dye at 590 nm. Under the optimized conditions, Beer’s law is obeyed over the concentration ranges of 0.4–12.0 and 0.2–3.5 μg  FFH for method A and method B, respectively, and the corresponding molar absorptivity values are 3.80 × 104 and 1.61 × 105 L . The Sandell’s sensitivity, detection, and quantification limits are also reported. The proposed methods were successfully applied to the determination of FFH in pure drug and commercial tablets. The accuracy and reliability of the proposed methods were further established by recovery studies via standard addition technique.

scholarly journals Spectrophotometric determination of dothiepin hydrochloride in pharmaceuticals through ion-pair complexation reaction

2012 ◽  
Vol 18 (2) ◽  
pp. 339-347 ◽  
Author(s):  
Sameer Abdulrahman ◽  
Kanakapura Basavaiah
Keyword(s):  
Ion Pair ◽  
Pure Form ◽  
Bromocresol Green ◽  
Bromophenol Blue ◽  
Complexation Reaction ◽  
Conditional Stability ◽  
Conditional Stability Constant ◽  
Accuracy And Precision ◽  
Significant Difference

Two simple, sensitive and extraction-free spectrophotometric methods are described for the determination of dothiepin hydrochloride (DOTH) both in pure form and in pharmaceutical tablets. The methods are based on ion-pair complex formation between dothiepin base (DOT) and two acidic dyes, namely, bromophenol blue (BPB) or bromocresol green (BCG) with absorption maximum at 425 nm for BPB method or 430 nm for BCG method. Beer?s law is obeyed over the concentration ranges of 1.0-15.0 and 1.0-17.5 ?g mL-1 DOT for BPB and BCG methods, respectively. The molar absorptivity values and Sandell?s sensitivity values are reported for both methods. The limits of detection (LOD) and quantification (LOQ) were calculated to be 0.18 and 0.53 ?g mL-1 for BPB method, and 0.17 and 0.50 ?g mL-1 for BCG method, respectively. The stoichiometry of the complex in either case was found to be 1: 1 and the conditional stability constant (KF) of the complexes has also been calculated. The proposed methods were applied successfully to the determination of DOTH in pure form and in its tablet form with good accuracy and precision. Statistical comparison of the results was performed using Student's t-test and variance ratio F-test at 95% confidence level and there was no significant difference between the official and proposed methods with regard to accuracy and precision. Further, the validity of the proposed methods was confirmed by recovery studies via standard addition technique.

scholarly journals Simple Atomic Absorption Spectroscopic and Spectrophotometric Methods for Determination of Pioglitazone Hydrochloride and Carvedilol in Pharmaceutical Dosage Forms

2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Afaf A. Abdelmonem ◽  
Gamal H. Ragab ◽  
Hisham Hashem ◽  
Eman A. Bahgat
Keyword(s):  
Atomic Absorption ◽  
Acidic Medium ◽  
Methylene Chloride ◽  
Ion Pair ◽  
Fast Green ◽  
Experimental Conditions ◽  
Pharmaceutical Dosage Forms ◽  
Spectrophotometric Methods ◽  
Orange G

This study represents simple atomic absorption spectroscopic and spectrophotometric methods for determination of pioglitazone hydrochloride (PGZ-HCl) and carvedilol (CRV) based on formation of ion-pair associates between drugs and inorganic complex, bismuth(III) tetraiodide (Method A) and between drugs and organic acidic dyes, fast green and orange G (Method B). Method A is based on formation of ion-pair associate between drugs and bismuth(III) tetraiodide in acidic medium to form orange-red ion-pair associates, which can be quantitatively determined by two different procedures. The formed ion-pair associate is extracted by methylene chloride, dissolved in acetone, dried, and then decomposed by hydrochloric acid, and bismuth content is determined by direct atomic absorption spectrometric technique (Procedure 1) or extracted by methylene chloride, dissolved in acetone, and quantified spectrophotometrically at 490 nm (Procedure 2). Method B is based on formation of ion-pair associate between drugs and either fast green dye or orange G dye in acidic medium to form ion-pair associates. The formed ion-pair associate is extracted by methylene chloride and quantified spectrophotometrically at 630 nm (for fast green dye method) or 498 nm (for orange G dye method). Optimal experimental conditions have been studied. Both methods are applied for determination of the drugs in tablets without interference.

scholarly journals Extractive Spectrophotometric Determination of Nortriptyline Hydrochloride Using Sudan II, IV and Black B

2001 ◽  
Vol 69 (2) ◽  
pp. 151-160
Author(s):  
A. Amin ◽  
H. Saleh
Keyword(s):  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Calibration Graph ◽  
Official Method ◽  
Spectrophotometric Methods ◽  
Sudan Black B ◽  
Relative Standard ◽  
Nortriptyline Hydrochloride

A simple spectrophotometric methods has been developed for the determination of nortriptyline hydrochloride in pure and in pharmaceutical formulations based on the formation of ion-pair complexes with sudun II (SII), sudan (IV) (SIV) and sudan black B (SBB). The selectivity of the method was improved through extraction with chloroform. The optimum conditions for complete extracted colour development were assessed. The absorbance measurements were made at 534, 596 and 649 nm for SII, SIV and SBB complexes, respectively. The calibration graph was linear in the ranges 0.5- 280. 0.5- 37.5 and 0.5 – 31.0 μg ml−1 of the drug usiny the same reagents, respectively. The precision of the procedure was checked by calculating the relative standard deviation of ten replicate determinations on 15 μg ml−1 of nortriptyline HCI and was found to be 1.7, 1.3 and 1.55% using SII, SIV, and SBB complexes, respectively. The molar absorptivity and Sandell sensitivity for each ion-pair were calculated. The proposed methods were successfully applied to the deterniination of pure nortriptyline HCI and in pharmaceutical formulations, and the results demonstrated that the method is equally accurate, precise and reproducible as the official method.

Validated Spectrophotometric Determination of Rizatriptan Benzoate in Pharmaceutical Formulations using Alizarin Derivatives

2019 ◽  
Vol 10 (01) ◽  
Author(s):  
El Sheikh R ◽  
Hassan W. S. ◽  
Gouda A. A. ◽  
Al OwairdhiA. ◽  
Al Hassani K K H
Keyword(s):  
Standard Addition ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Optimum Conditions ◽  
Reaction Conditions ◽  
Alizarin Red ◽  
Rizatriptan Benzoate ◽  
Spectrophotometric Methods ◽  
Relative Standard

Two simple, sensitive, accurate, precise and economical spectrophotometric methods have been developed and validated for the determination of rizatriptan benzoate (RZT) in pure form and pharmaceutical formulations. These methods were based on the formation of charge transfer complex between RZT as n-electron donor and alizarin red S (ARS) or quinalizarin (Quinz) as π-acceptor in methanol to form highly colored chromogens which showed an absorption maximum at 532 and 574 nm using ARS and Quinz, respectively. The optimization of the reaction conditions such as the type of solvent, reagent concentration and reaction time were investigated. Under the optimum conditions, Beer’s law is obeyed in the concentration ranges 1.0-16 and 2.0-20 g mL-1 using ARS and Quinz, respectively with good correlation coefficient (r2 ≥ 0.9996) and with a relative standard deviation (RSD% ≤ 1.16). The molar absorptivity, Sandell sensitivity, detection and quantification limits were also calculated. The methods were successfully applied to the determination of RZT in its pharmaceutical formulations and the validity assesses by applying the standard addition technique. Results obtained by the proposed methods for the pure RZT and commercial tablets agreed well with those obtained by the reported method.

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