Rapid titrimetric and spectrophotometric methods for Salbutamol Sulphate in pharmaceuticals using N- bromosuccimide

Department of Chemistry, University of Mysore, Manasagangotri, Mysore-570 006, India.
Acta Pharmaceutica (Impact Factor: 0.91). 03/2007; 57(1):87-98. DOI: 10.2478/v10007-007-0007-7
Source: PubMed


One titrimetric and two spectrophotometric methods which are simple, sensitive and rapid are described for the assay of salbutamol sulphate (SBS) in bulk drug and in tablet dosage forms using N-bromosuccinimide (NBS) and two dyes, rhodamine-B and methylene blue, as reagents. In titrimetry, aqueous solution of salbutamol sulphate is treated with a measured excess of NBS in acetic acid medium and after the oxidation of SBS is complete, the unreacted oxidant is determined iodometrically. Spectrophotometric methods entail addition of a known excess of NBS in acid medium followed by the determination of residual oxidant by reacting with a fixed amount of either rhodamine B and measuring the absorbance at 555 nm (method A) or methylene blue and measuring the absorbance at 665 nm (method B). In all methods, the amount of NBS reacting corresponds to the amount of SBS content. Titrimetric method is applicable over 1.74 x 10(-4) - 8.68 x 10(-4) mol L(-1) range and the reaction stoichiometry is found to be 1:6 (SBS:NBS). In spectrophotometric methods, the absorbance is found to increase linearly with the concentration of SBS, which is corroborated by the correlation of coefficients of 0.9993 and 0.9988 for method A and method B, respectively. The systems obey Beer's law for 0.25-1.75 microg mL(-1) (method A) and 0.5-5.0 microg mL(-1) (method B). The calculated apparent molar absorptivity values were found to be 2.10 x 10(5) and 6.16 x 10(4) L mol(-1) cm(-1), for method A and method B, respectively. The limits of detection and quantification are also reported for both spectrophotometric methods. Intra-day and inter-day precision and accuracy for the developed methods were evaluated. The methods were successfully applied to the assay of SBS in tablet and capsule formulations and the results were statistically compared with those of a reference method. No interference was observed from common tablet adjuvants. The accuracy and reliability of the methods were further ascertained by recovery experiments via the standard-addition technique.

    • "SAL is official in IP, BP and USP[2–4] and the official method for quantification of SAL bulk drug is non-aqueous titration, while for syrup and injection dosage form, colorimetric method is employed. Electrochemical techniques,[5–7] chromatographic methods,[8–10] spectrophotometric methods[11–15] and automated methods such as flow injection analysis[1617] are also reported for detection of SAL in bulk drug and pharmaceutical formulation. The reported chromatographic methods for estimation of SAL are time consuming while official electrochemical and colorimetric methods are less selective and sensitive. "
    [Show abstract] [Hide abstract]
    ABSTRACT: A simple, precise, reproducible and accurate spectrofluorimetric method for estimation of Salbutamol sulphate (SAL) in bulk drug and various dosage forms has been developed. This method is based on formation of inclusion complex of SAL in β-cyclodextrin (BCD) which gives fluorescence at excitation wavelength of 279.6 nm and emission wavelength of 609.8 nm in water. Formation of inclusion complex of drug with BCD enhances fluorescence intensity of drug leads to increased sensitivity. The developed method was validated according to ICH guidelines with respect to accuracy, precision, linearity, limit of detection, limit of quantification. Linearity was observed in the range of 4-20 μg/ml with correlation coefficient of 0.9982. The simplicity of the method permitted rapid analysis suitable for routine control. The developed method was successfully applied for the estimation of SAL in different marketed dosage forms like tablets, syrup and aerosol.
    No preview · Article · Oct 2010
  • [Show abstract] [Hide abstract]
    ABSTRACT: The kinetics of ruthenium (III)-catalyzed oxidative cleavage of thiamine hydrochloride (THM, Vitamin B1) with N-bromosuccinimide (NBS) in HCl medium has been investigated at 308K. The oxidation reaction follows the rate law, −d[NBS]/dt=k[NBS][Ru(III)]a[THM]b[H+]−c[Cl−]−d, where a, b, c and d are less than unity. The stiochiometry of the reaction was found to be 1:1, and 2-(4-methyl thiazol-5-yl) ethanol and 4-amino-2-methylpyrimidine-5-carbaldehyde were identified as the oxidation products of THM. The reaction was examined with reference to variation of ionic strength of the medium and addition of the deduction product NBS, succinamide (RNH). The change in relative permittivity of the medium affected by changing the solvent composition with acetonitrile has been studied. The reaction constants involved in the mechanism were computed. The overall activation parameters have been evaluated from the Arrhenius plot. HOBr has been postulated as the reactive oxidizing species. The observed results have been explained by plausible mechanisms and the relative rate laws have been deduced.
    No preview · Article · Apr 2009 · Journal of Molecular Catalysis A Chemical
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Metronidazole (MTZ) and tinidazole (TNZ) belong to nitroimidazole group of drugs used to treat infections such as ameobiasis, giardiasis and trichomoniasis. The kinetics of oxidation of MTZ and TNZ with N-bromosuccinimide (NBS) in perchloric acid medium has been investigated at 308 K. A 1:1 stoichiometry has been observed in both MTZ and TNZ cases. The oxidation reactions of both MTZ and TNZ follow the same rate law, -d[NBS]/dt = [NBS][Sub][H+]. However, in case of MTZ, at higher concentrations of H+ (0.006–0.01 mol dm−3), the rate law obtained is -d[NBS]/dt = [NBS][MTZ][H+]−1. Accelerating effect of [Cl-] and retardation of the added succinimide on the reaction rate have been observed in the case of MTZ. The reactions were examined with reference to changes in concentration of added neutral salt, ionic strength and dielectric permittivity of the medium. The overall activation parameters have been evaluated from the Arrhenius plot. The reactive oxidizing species of NBS have been determined. The main oxidation products were identified by IR and 1H NMR spectral analyses. The observed results have been explained by plausible mechanisms and the relative rate laws have been deduced.
    Preview · Article · Jun 2009 · Journal of the Iranian Chemical Society
Show more