scholarly journals Sensitive and rapid titrimetric and spectrophotometric methods for the determination of stavudine in pharmaceuticals using bromate-bromide and three dyes

2008 ◽  
Vol 80 (2) ◽  
pp. 253-262 ◽  
Author(s):  
Kanakapura Basavaiah ◽  
Veeraiah Ramakrishna ◽  
Chikkaswamy Somashekar ◽  
Urdigere R. Anil Kumar

Four sensitive and rapid methods for the determination of stavudine (STV) in bulk drug and in dosage forms were developed and optimized. In titrimetry, aqueous solution of STV was treated with a known excess of bromate-bromide in HCl medium followed by estimation of unreacted bromine by iodometric back titration. Spectrophotometric methods involve the addition of a measured excess of bromate-bromide in HCl medium and subsequent estimation of the residual bromine by reacting with a fixed amount of methyl orange, indigocarmine or thymol blue followed by measurement of absorbance at 520 nm (method A), 610 nm (method B) or 550 nm (method C). In all the methods, the amount of bromate reacted corresponds to the amount of STV. Calculations in titrimetry were based on a 1:0.666 (STV:KBrO3) stoichiometry and the method was found to be applicable over 3.5-10 mg range. A linear increase in absorbance with concentration of STV was observed in the spectrophotometric methods, and the Beer's law was obeyed over the concentration ranges 0.125-1.75, 1-10 and 1-9.0 µg mL-1 STV for method A, method B and method C, respectively. The methods when applied to the determination of STV in tablets and capsules were found to give satisfactory results.

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
O. Zenita ◽  
K. Basavaiah

Two titrimetric and two spectrophotometric methods are described for the assay of famotidine (FMT) in tablets using N-bromosuccinimide (NBS). The first titrimetric method is direct in which FMT is titrated directly with NBS in HCl medium using methyl orange as indicator (method A). The remaining three methods are indirect in which the unreacted NBS is determined after the complete reaction between FMT and NBS by iodometric back titration (method B) or by reacting with a fixed amount of either indigo carmine (method C) or neutral red (method D). The method A and method B are applicable over the range of 2–9 mg and 1–7 mg, respectively. In spectrophotometric methods, Beer's law is obeyed over the concentration ranges of 0.75–6.0 μg mL-1(method C) and 0.3–3.0 μg mL-1(method D). The applicability of the developed methods was demonstrated by the determination of FMT in pure drug as well as in tablets.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Kanakapura Basavaiah ◽  
Nagib A. S. Qarah ◽  
Sameer A. M. Abdulrahman

Two simple methods are described for the determination of ethionamide (ETM) in bulk drug and tablets using cerium (IV) sulphate as the oxidimetric agent. In both methods, the sample solution is treated with a measured excess of cerium (IV) solution in H2SO4 medium, and after a fixed standing time, the residual oxidant is determined either by back titration with standard iron (II) solution to a ferroin end point in titrimetry or by reacting with o-dianisidine followed by measurement of the absorbance of the orange-red coloured product at 470 nm in spectrophotometry. In titrimetry, the reaction proceeded with a stoichiometry of 1 : 2 (ETM : Ce (IV)) and the amount of cerium (IV) consumed by ETM was related to the latter’s amount, and the method was applicable over 1.0–8.0 mg of drug. In spectrophotometry, Beer’s law was obeyed over the concentration range of 0.5–5.0 μg/mL ETM with a molar absorptivity value of 2.66 × 104 L/(mol·cm). The limits of detection (LOD) and quantification (LOQ) calculated according to ICH guidelines were 0.013 and 0.043 μg/mL, respectively. The proposed titrimetric and spectrophotometric methods were found to yield reliable results when applied to bulk drug and tablets analysis, and hence they can be applied in quality control laboratories.


2018 ◽  
Vol 35 (3) ◽  
pp. 109
Author(s):  
Badiadka Narayana ◽  
K. Veena ◽  
K. Ashwani ◽  
Divya N. Shetty

A new spectrophotometric method is proposed for the assay of ranitidine hydrochloride (RNH) in bulk drug and in its dosage forms using ceric ammonium sulphate (CAS) and two dyes, malachite (MAG) green and crystal violet (CV) as reagents. The method involves the addition of a known excess of ceric ammonium sulphate to ranitidine hydrochloride in acid medium, followed by the determination of unreacted CAS by reacting with a fixed amount of malachite green or crystal violet and measuring the absorbance at 615 or 582 nm respectively against the reagent blank. The Beer’s law is obeyed in the concentration range of 0.4-8.0 μg/ml of ranitidine hydrochloride (RNH) for RNH-MAG system and 0.2-1.6μg/ml of ranitidine hydrochloride for RNH-CV system. The molar Absorptivity, Sandell’s sensitivity for each system were calculated. The method has been successfully applied to the determination of ranitidine hydrochloride in pure and dosage forms.


2011 ◽  
Vol 47 (2) ◽  
pp. 251-260 ◽  
Author(s):  
Kanakapura Basavaiah Vinay ◽  
Hosakere Doddarevanna Revanasiddappa ◽  
Okram Zenita Devi ◽  
Pavagada Jagannathamurthy Ramesh ◽  
Kanakapura Basavaiah

One titrimetric and two spectrophotometric methods have been described for the determination of ofloxacin (OFX) in bulk drug and in tablets, employing N-Bromosuccinimide as an analytical reagent. The proposed methods involve the addition of a known excess of NBS to OFX in acid medium, followed by determination of unreacted NBS. In titrimetry, the unreacted NBS is determined iodometrically, and in spectrophotometry, unreacted NBS is determined by reacting with a fixed amount of either indigo carmine (Method A) or metanil yellow (Method B). In all the methods, the amount of NBS reacted corresponds to the amount of OFX. Titrimetry allows the determination of 1-8 mg of OFX and the calculations are based on a 1:5 (OFX:NBS) reaction stoichiometry. In spectrophotometry, Beer's law is obeyed in the concentration ranges 0.5-5.0 µg/mL for method A and 0.3-3.0 µg/mL for method B. The molar absorptivities are calculated to be 5.53x10(4) and 9.24x10(4) L/mol/cm for method A and method B, respectively. The methods developed were applied to the assay of OFX in tablets, and results compared statistically with those of a reference method. The accuracy and reliability of the methods were further ascertained by performing recovery tests via the standard-addition method.


2007 ◽  
Vol 57 (2) ◽  
pp. 211-220 ◽  
Author(s):  
Kanakapura Basavaiah ◽  
Veeraiah Ramakrishna ◽  
Urdigere Kumar

Use of ceric ammonium sulphate and two dyes, methyl orange and indigo carmine, in the determination of lansoprazole in pharmaceuticalsTwo spectrophotometric methods are proposed for the assay of lansoprazole (LPZ) in bulk drug and in dosage forms using ceric ammonium sulphate (CAS) and two dyes, methyl orange and indigo carmine, as reagents. The methods involve addition of a known excess of CAS to LPZ in acid medium, followed by determination of residual CAS by reacting with a fixed amount of either methyl orange, measuring the absorbance at 520 nm (method A), or indigo carmine, measuring the absorbance at 610 nm (method B). In both methods, the amount of CAS reacted corresponds to the amount of LPZ and the measured absorbance was found to increase linearly with the concentration of LPZ, which is corroborated by the correlation coefficients of 0.9979 and 0.9954 for methods A and B, respectively. The systems obey Beer's law for 0.5-7.0 μg mL-1and 0.25-3.0 μg mL-1for methods A and B, respectively. The apparent molar absorptivities were calculated to be 3.0 x 104and 4.4 x 104L mol-1cm-1for methods A and B, respectively. The limits of detection (LOD) and quantification (LOQ) were calculated to be 0.08 and 0.25 μg mL-1for method A, and 0.09 and 0.27 μg mLs-1for method B, respectively. The intra-day and inter-day precision and accuracy of the methods were evaluated according to the current ICH guidelines. Both methods were of comparable accuracy (er≤ 2 %). Also, both methods are equally precise as shown by the relative standard deviation values < 1.5%. No interference was observed from common pharmaceutical adjuvants. The accuracy of the methods was further ascertained by performing recovery studies using the standard addition method. The methods were successfully applied to the assay of LPZ in capsule preparations and the results were statistically compared with those of the literature UV-spectrophotometric method by applying Student'st-test andF-test.


2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Kudige N. Prashanth ◽  
Kanakapura Basavaiah

Three simple and sensitive spectrophotometric methods are proposed for the determination of atenolol (ATN) in bulk drug and tablets. The methods are based on the bromination of ATN by the bromine generatedin situby the action of the acid on the bromate–bromide mixture followed by the determination of unreacted bromine by reacting with a fixed amount of either meta-cresol purple (MCP) and measuring the absorbance at 540 nm (method A) and 445 nm (method B) or erioglaucine (EGC) and measuring the absorbance at 630 nm (method C). Beer's law is valid within the concentration ranges of 1.0–20.0, 2.0–40.0 and 1.0–8.0 μg/mL for method A, method B and method C, respectively. The calculated molar absorptivities were found to be 1.20×104, 4.51×103and3.46×104  L/mol⋅cmfor method A, method B and method C, respectively. Sandell’s sensitivity values, correlation coefficients, limits of detection and quantification are also reported. Recovery results were statistically compared with those of a reference method by applying Student’st- andF-test. The novelty of the present study is the measurement of two different colors using MCP, that is, red-pink color of MCP in acid medium at 540 nm and yellowish-orange color of brominated MCP at 445 nm.


2011 ◽  
Vol 17 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Zenita Devi ◽  
K. Basavaiah ◽  
K.B. Vinay

Three simple and sensitive spectrophotometric methods are described for the determination of domperidone (DOM) in bulk drug and in dosage forms using bromate-bromide mixture as brominating agent in acid medium and three dyes, meta-cresol purple (MCP), amaranth (AMR) and erioglaucine (EGC). The methods involve the addition of a known excess of bromate-bromide mixture to an acidified solution of DOM followed by the determination of the residual bromine by reacting with a fixed amount of either MCP dye and measuring the absorbance at 530 nm (method A) or AMR dye and measuring the absorbance at 520 nm (method B) or EGC dye and measuring the absorbance at 630 nm (method C). Beer?s law is obeyed over the concentration ranges, 0.63 - 10.0, 0.25-4.0 and 0.13-2.0 ?g mL-1 for method A, method B and method C, respectively. The apparent molar absorptivities are calculated to be 3.751 ? 104, 6.604 ? 104 and 1.987 ? 105 L mol-1cm-1 for method A, method B and method C, respectively and the corresponding sandell sensitivity values are 0.011, 0.006 and 0.002 ?g cm-2. The limit of detection and the limit of quantification are also reported for all the three methods. No interference was observed from common additives found in pharmaceutical preparations. Statistical comparisons of the results with those of the reference method showed an excellent agreement, and indicated no significant difference in accuracy and precision. The accuracy and reliability of the methods were further ascertained by performing recovery tests via standard-addition technique.


2012 ◽  
Vol 18 (3) ◽  
pp. 449-458 ◽  
Author(s):  
Srinivas Raghu ◽  
Kanakapura Basavaiah

One titrimetric and two spectrophotometric methods are described for the determination of cyproheptadine hydrochloride (CPH) in bulk drug and tablets employing N-bromosuccinimide (NBS) as a brominating agent and two dyes, erioglaucine (EG) and meta-cresol purple (MCP) as auxiliary reagents. In titrimetry, a measured excess of NBS is added to an acidified solution of CPH and the unreacted NBS is determined iodometrically. Spectrophotometry involves the addition of a known excess of NBS to CPH in acid medium followed by estimation of residual NBS by reacting with a fixed amount of either erioglaucin and measuring the absorbance at 540 nm (method A) or meta-cresol purple and measuring the absorbance at 630 nm (method B). Titrimetric procedure is applicable over the range of 1.5-15 mg of CPH, and the reaction stoichiometry is found to be 1: 2 (CPH: NBS). The spectrophotometric methods are applicable over the ranges of 0.1-2.0 ?g mL-1 (method A) and 0.4-12 ?g mL-1 (method B). The molar absorptivities are calculated to be 1.4 ? 105 and 2.2?104 Lmol-1cm-1 for method A and method B, respectively, and the corresponding Sandell sensitivity values are 0.0023 and 0.0141 ?g cm-2. The limits of detection are calculated and found to be 0.03 and 0.24 ?g mL-1 for method A and method B, respectively with corresponding limits of quantification 0.09 and 0.71. The methods were applied to the assay of CPH in tablets, and the results were compared statistically with those of a reference method.


2007 ◽  
Vol 4 (1) ◽  
pp. 117-127 ◽  
Author(s):  
K. Basavaiah ◽  
B. C. Somashekar

One titrimetric and two spectrophotometric methods are presented for the assay of metaprolol tartrate (MPT) in bulk drug and in tablets. The methods employ N-bromosuccinimide (NBS) as the oxidimetric reagent and two dyes, methyl orange and indigo carmine as spectrophotometric reagents. In titrimetry, an acidified solution of MPT is treated with a known excess amount of NBS and after a definite time, the unreacted oxidant is determined by iodometric back titration. Spectrophotometry involves adding a measured excess of NBS to MPT in acid medium followed by determination of residual NBS by reacting with a fixed amount of either methyl orange and measuring the absorbance at 520 nm (Method A) or indigo carmine and measuring the absorbance at 610 nm (Method B). In all the methods, the amount of NBS reacted corresponds to the amount of MPT. Reaction conditions have been optimized. Titrimetry allows the determination of 1 - 12 mg of MPT and the calculations are based on a 1: 4 (MPT: NBS) reaction stoichiometry. In spectrophotometry, the measured absorbance is found to increase linearly with the concentration of MPT serving as basis for quantitation. The systems obey Beer’s law for 0.5 - 4.0 μg mL-1and 1.25 - 10.0 μg mL-1for method A and method B, respectively. The apparent absorptivities are calculated to 1.07 × 105be and 4.22 × 104L mol cm-1for method A and method B, respectively. The methods developed were applied to the assay of MPT in commercial tablet formulations, and the results were compared statistically with those of a reference method. The accuracy and reliability of the methods were further ascertained by performing recovery tests via standard-addition method.


2008 ◽  
Vol 14 (3) ◽  
pp. 185-190
Author(s):  
Kanakapura Basavaiah ◽  
Urdigere Kumar ◽  
Kalsang Tharpa

Three new, simple, and cost-effective visible spectrophotometric methods are proposed for determination of gatifloxacin (GTF) using bromate-bromide mixture, and three dyes, methyl orange, indigocarmine and thymol blue, as reagents. The methods engross the addition of a known excess of bromate-bromide mixture to GTF in hydrochloric acid medium followed by determination of residual bromine by reacting with a fixed amount of either methyl orange and measuring the absorbance at 520 nm (method A) or indigo carmine and measuring the absorbance at 610 nm (method B) or thymol blue and measuring the absorbance at 550 nm (method C). In all the methods, the amount of bromine reacted corresponds to the amount of GTF, and the absorbance is found to increase linearly with the concentration of GTF. Under the optimum conditions, GTF could be assayed in the concentration range 0.25-1.5, 0.5-6.0, and 0.5-10 mg/mL by method A, method B and method C, respectively. The apparent molar absorptivities are calculated to be 1.6x105, 4.0x104 and 3.2x104 L mol-1 cm-1 for the method A, method B and method C, respectively, and the corresponding Sandell sensitivity values are 0.0025, 0.010 and 0.012 ?g/cm2. The intra-day and inter-day precision, and the accuracy of the methods were evaluated as per the current ICH guidelines. The methods were successfully applied to the determination of GTF in pharmaceutical preparations without the interference from any of the pharmaceutical adjuvant.


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