SIMPLE AND HIGHLY SELECTIVE DIRECT STABILITY INDICATING ULTRAVIOLET AND INDIRECT VISIBLE SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF ENROFLOXACIN IN PHARMACEUTICALS

2021 ◽  
Vol 88 (6) ◽  
pp. 982-992
Author(s):  
N. Rajendraprasad
Keyword(s):  
Standard Addition ◽  
Uv Degradation ◽  
Degradation Study ◽  
Formation Reaction ◽  
Stability Indicating ◽  
Spectrophotometric Methods ◽  
The Stability ◽  
Simple Economic ◽  
Molar Extinction Coefficients

Three simple, economic, selective and accurate and precise spectrophotometric methods are developed for determination of enrofloxacin (EFX) in pharmaceuticals. Method A is based on the measurement of absorbance of EFX in 0.1M HOAc at 315 nm. The ketoxime formation reaction has been employed in method B, in which the absorbance measurement of EFX oxime product at 275 nm is described. The third method (Method C) is indirect one and is based on the oxidation of EFX by cerium(IV), reaction of unreacted cerium(IV) with p-toludine (p-TD) and measurement of coloured solution at 540 nm. The Beer’s law is obeyed in the concentration ranges of 1.2–24, 1–8, and 1–20 μg/mL EFX in methods A, B, and C, respectively, with the corresponding molar extinction coefficients of 1.52×104, 3.86×104, and 6.6×103 L/mol/cm. The regression coefficients of calibration lines are 0.9996, 0.9913, and –0.9965, in methods A, B, and C, respectively. The limits of detection (LOD) and quantification (LOQ) have also been reported for each method. The methods have been validated to check accuracy, precision, robustness and ruggedness. The application of the methods proposed to determine EFX in tablets has been described and the results have been compared with a standard method. The results of validation and application have been found to be with excellent agreement. The standard addition procedure has been adopted in recovery experiments to further ascertain the accuracy of the methods and the results of the experiments are well satisfied. The stability indicating ability of Method A has been studied by subjecting EFX to acid and alkaline hydrolysis, oxidative, thermal and UV degradation followed by measurement of absorbance of resultant EFX solutions at 315 nm. The results of degradation study indicated unsusceptible nature of EFX to any of the stress conditions.

scholarly journals Selective and Stability-Indicating Methods for the Simultaneous Determination of Mexiletine Hydrochloride and/or Its Related Substance: 2,6-Dimethylphenol

2008 ◽  
Vol 91 (4) ◽  
pp. 720-730
Author(s):  
Tarek S Belal ◽  
Rim S Haggag ◽  
Rasha A Shaalan
Keyword(s):  
Sodium Dodecyl ◽  
Coupling Reaction ◽  
Parent Drug ◽  
Related Substance ◽  
Selective Determination ◽  
Stability Indicating ◽  
Spectrophotometric Methods ◽  
First Derivative ◽  
The Stability

Abstract Four simple, rapid, sensitive, and selective analytical procedures were developed for determination of mexiletine hydrochloride (MX) and/or its related substance: 2,6-dimethylphenol (DMP). The latter is a synthetic impurity for which a maximum pharmacopeial limit is defined. The first method depends on derivative-ratio spectrophotometry, for which the first-derivative signals of the ratio spectra at 259 nm ( = 3 nm) are selected for the determination of MX. The second method is based on the spectrofluorometric measurement of MX in alkaline solution in the presence of 15 mM sodium dodecyl sulfate micellar medium at 292 nm (Ex 260 nm). The third method is based on liquid chromatographic (LC) separation of MX and DMP on an RP-C8 column with a mobile phase consisting of 50 mM Na2HPO4acetonitrile (60 + 40, adjusted to pH 2.4), and quantification of the analytes is achieved with UV detection at 212 nm based on peak area. The fourth method uses the coupling reaction of DMP with 2,6-dibromoquinone-4-chlorimide (DBQC) in borate buffer to form an intensely colored product that was spectrophotometrically measured using first-derivative amplitudes at 670 nm ( = 6nm) for the determination of DMP. Different variables affecting each method were carefully investigated and optimized. The reliability and analytical performance of the proposed methods, including linearity, range, precision, accuracy, and detection and quantitation limits, were statistically validated. The first 3 methods were successfully applied for the stability-indicating determination of MX in laboratory-prepared mixtures with DMP, as well as for the determination of MX in capsules. Also, the LC and the DBQC spectrophotometric methods permitted the selective determination of DMP in the presence of a large excess of the parent drug at or near the pharmacopeial limit (0.11).

scholarly journals Smart Stability-Indicating Spectrophotometric Methods for Determination of Binary Mixtures Without Prior Separation

2008 ◽  
Vol 91 (2) ◽  
pp. 299-310 ◽  
Author(s):  
Mohammad G El-Bardicy ◽  
Hayam M Lotfy ◽  
Mohammad A El-Sayed ◽  
Mohammad F El-Tarras
Keyword(s):  
Degradation Product ◽  
Total Content ◽  
Standard Addition ◽  
Pharmaceutical Formulations ◽  
Assay Method ◽  
Isosbestic Point ◽  
Subtraction Method ◽  
Stability Indicating ◽  
Spectrophotometric Methods

Abstract Ratio subtraction and isosbestic point methods are 2 innovating spectrophotometric methods used to determine vincamine in the presence of its acid degradation product and a mixture of cinnarizine (CN) and nicergoline (NIC). Linear correlations were obtained in the concentration range from 840 g/mL for vincamine (I), 622 g/mL for CN (II), and 636 g/mL for NIC (III), with mean accuracies 99.72 0.917 for I, 99.91 0.703 for II, and 99.58 0.847 and 99.83 1.039 for III. The ratio subtraction method was utilized for the analysis of laboratory-prepared mixtures containing different ratios of vincamine and its degradation product, and it was valid in the presence of up to 80 degradation product. CN and NIC in synthetic mixtures were analyzed by the 2 proposed methods with the total content of the mixture determined at their respective isosbestic points of 270.2 and 235.8 nm, and the content of CN was determined by the ratio subtraction method. The proposed method was validated and found to be suitable as a stability-indicating assay method for vincamine in pharmaceutical formulations. The standard addition technique was applied to validate the results and to ensure the specificity of the proposed methods.

scholarly journals 2-Hydroxy-4-Methoxybenzophenone Oxime as an Analytical Reagent for Copper(II)

2005 ◽  
Vol 2 (2) ◽  
pp. 161-164 ◽  
Author(s):  
Miss Krishna Purohit ◽  
K. K. Desai
Keyword(s):  
Molar Absorptivity ◽  
Complex Formation Reaction ◽  
Formation Reaction ◽  
Spectrophotometric Methods ◽  
Gravimetric Determination ◽  
Analytical Reagent ◽  
Gibb’S Free Energy ◽  
The Stability ◽  
Metal Ligand

2-Hydroxy-4-methoxybenzophenoneoxime (HMBO) was developed as a new analytical reagent for the gravimetric determination of Cu(II). In pH 2.5-9.0 the reagent gives brown coloured precipitate with Cu(II). Spectrophotometric methods revealed that the stoichiometry of the complex is 1:2 (metal: ligand). Beer's law is obeyed up to 31.75 ppm of Cu(II). Molar absorptivity and Sandell's sensitivity at 400 nm were found to be 7.0×102L mol-1cm-1and 0.090 μg/cm2respectively. The stability constant of Cu(II)-HMBO complex is found to be 6.13×109. Gibb’s free energy change for complex formation reaction was found to be -13.93 Kcal/mol. The reagent can be used for the analysis of brass.

scholarly journals Charge Transfer Complexes of Ketotifen with 2,3-Dichloro-5,6-dicyano-p-benzoquinone and 7,7,8,8-Tetracyanoquodimethane: Spectroscopic Characterization Studies

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2039
Author(s):  
Gamal A. E. Mostafa ◽  
Ahmed Bakheit ◽  
Najla AlMasoud ◽  
Haitham AlRabiah
Keyword(s):  
Charge Transfer ◽  
Spectroscopic Characterization ◽  
Molar Ratio ◽  
Charge Transfer Complexes ◽  
Physical Parameters ◽  
Spectrophotometric Methods ◽  
Theoretical Approaches ◽  
The Stability ◽  
Ct Complexes

The reactions of ketotifen fumarate (KT) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π acceptors to form charge transfer (CT) complexes were evaluated in this study. Experimental and theoretical approaches, including density function theory (DFT), were used to obtain the comprehensive, reliable, and accurate structure elucidation of the developed CT complexes. The CT complexes (KT-DDQ and KT-TCNQ) were monitored at 485 and 843 nm, respectively, and the calibration curve ranged from 10 to 100 ppm for KT-DDQ and 2.5 to 40 ppm for KT-TCNQ. The spectrophotometric methods were validated for the determination of KT, and the stability of the CT complexes was assessed by studying the corresponding spectroscopic physical parameters. The molar ratio of KT:DDQ and KT:TCNQ was estimated at 1:1 using Job’s method, which was compatible with the results obtained using the Benesi–Hildebrand equation. Using these complexes, the quantitative determination of KT in its dosage form was successful.

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.

Stability-Indicating Liquid Chromatographic Procedure for Determination of Allantoin in Cosmetic Lotion

1988 ◽  
Vol 71 (2) ◽  
pp. 290-294
Author(s):  
Ramesh J Trivedi
Keyword(s):  
Degradation Products ◽  
Glyoxylic Acid ◽  
Uv Detector ◽  
Stability Indicating ◽  
Assay Procedure ◽  
Relative Standard ◽  
The Stability ◽  
Chromatographic Parameters ◽  
Liquid Chromatographic

Abstract A sensitive, specific liquid chromatographic (LC) procedure was developed for determination of allantoin [(2,5-dioxo-4--imidaazolidinyl) urea or 5-ureidohydantion] in cosmetic lotion. A reverse-phase, ionsuppression mechanism separated allantoin from interfering constituents of the sample matrix, and the compound was determined with a UV detector at 240 nm with a sensitivity limit of ((.20 mg/mL. The chromatographic parameters were optimized for retention time, efficiency, and relative response to the analyte. The assay procedure was validated with spiked laboratory-prepared samples at 100 ± 15% levels. An average recovery of 99.4% with a relative standard deviation of 1.5% (n = 7) was obtained. The stability-indicating characteristics of the method were established by recovery study (99.8%) of samples spiked with known degradation products (urea, allantoic acid, and glyoxylic acid).

scholarly journals Determination of Rosuvastatin in the Presence of Its Degradation Products by a Stability-Indicating LC Method

2005 ◽  
Vol 88 (4) ◽  
pp. 1142-1147 ◽  
Author(s):  
Tushar N Mehta ◽  
Atul K Patel ◽  
Gopal M Kulkarni ◽  
Gunta Suubbaiah
Keyword(s):  
Degradation Products ◽  
Stability Study ◽  
Tablet Formulation ◽  
Assay Method ◽  
Forced Degradation ◽  
Degradation Study ◽  
Stability Indicating ◽  
Degraded Samples ◽  
Accelerated Stability

Abstract A forced degradation study was successfully applied for the development of a stability-indicating assay method for determination of rosuvastatin Ca in the presence of its degradation products. The method was developed and optimized by analyzing the forcefully degraded samples. Degradation of the drug was done at various pH values. Moreover, the drug was degraded under oxidative, photolytic, and thermal stress conditions. Mass balance between assay values of degraded samples and generated impurities was found to be satisfactory. The proposed method was able to resolve all of the possible degradation products formed during the stress study. The developed method was successfully applied for an accelerated stability study of the tablet formulation. The major impurities generated during the accelerated stability study of the tablet formulation were matches with those of the forced degradation study. The developed method was validated for determination of rosuvastatin Ca, and the method was found to be equally applicable to study the impurities formed during routine and forced degradation of rosuvastatin Ca.

scholarly journals 2-Hydroxy-5-methylbenzophenone oxime(HMBO) as an Analytical Reagent for Gravimetric Determination of Cu(II)

2007 ◽  
Vol 4 (1) ◽  
pp. 97-102 ◽  
Author(s):  
S. K. Shingadia ◽  
K. K. Desai
Keyword(s):  
Copper Ion ◽  
Molar Absorptivity ◽  
Ratio Method ◽  
Formation Reaction ◽  
Gravimetric Determination ◽  
Analytical Reagent ◽  
Gibb’S Free Energy ◽  
The Stability ◽  
Job's Method

2-Hydroxy-5-methylbenzophenone oxime (HMBO) was developed as a new analytical reagent for the gravimetric determination of divalent copper ion. In pH rang of 3.0 to 6.0, the reagent gives a buff colored precipitate with Cu(II). Job’s method and mole ratio method revealed that the stoichiometry of the complex is 1:2 (metal: ligand). Beer’s law is obeyed up to 61.25 ppm of Cu(II). Molar absorptivity and Sandell’s sensitivity at 400 nm were found to be 6.32 × 102L mol-1cm-1and 0.359 μg/cm2respectively. The stability constant of Cu(II)-HMBO complex is found to be 2.43 × 109. Gibb’s free energy change for complex formation reaction was found to be -12.88 Kcal/mol. The reagent can be used for the analysis of brass and alloy.

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