Spectrophotometric determination of salbutamol in salbutamol syrup
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Date
2001
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Publisher
University of Colombo: UC(SCI).
Abstract
There has been no separate analytical monograph for salbutamol syrup given in either British pharamacopoea (BP) or United State pharmacopea (USP). The conventional spectrophotometric method given in BP for salbutamol tablets cannot be employed for estimation of salbutamol in its liquid in its liquid dosage forms due to the interference from esters of hydroxybenzoic acid (preservative) and flavanoid constituents present in compounds used as flavours. The interference is due to the absorption of these compounds at 276 nm which is the wavelength recommended for spectrophotometric determination of salbutamol. Though there is a method of analysis in Indian pharmacopoeia for salbutamol syrup the cost of analysis is found to be comparatively high due to the use of very expensive complexing reagent. Apart from this, it is also found that the shelf-life of the commercial reagent is very short because of its instability due to liquification followed by degradation. This method was developed on the basis of a qualitative colorimetric method given in British phamacopoea Cordex (BPC) for both salbutamol and Salbutamol sulphate. The aim is to use it as a simple, rapid and reliable analytical method for a determination of sabutamol in sabutamol syrup. The formation of a purplish of a purplish red complex by the reaction between salbutamol and 4 - aminophenazone (complexing agent) in an alkaline borate buffer (pH=10) medium (above pH 8.5) in presence of potassium of potassium hexacynoferrate (III) is a qualitative test of identity. This coloured complex gives a sharp absorption peak in the visible range at 505nm. It was found that the system obeys Beer's law. The reagent concentrations were optimized using a fixed amount of salbutamol. The reaction conditions such as pH (8.5), temperature (25-30§C), equilibration time (20 minute)etc. were also optimized. The colour stability of the complex was studied by time scanning. Under the optimum conditions, the moral absorptivity was found to be 12,857 dm3 mol-1 cm1.Reproducibility and repeatability of results under optimim conditions were verified. The percentage of recovery was found to be 99.85 - 100.50 with SD 0.68 percent (n=5). The interference from preservatives and flavours was eliminated by extracting the sample acidified with 0.05 M H2SO4 to pH2, with several portions of diethyl ether. The validation of this method, was established by analyzing several brand products of slabutamol syrup available in the market for the content of salbutamol. The results obtained from this method were statistically well compared with those obtained with the use of the standard official method given in the Indian Pharmacopoeia.
Description
Dissertation: M.Sc. , University of Colombo: UC(SCI), 2001.
Keywords
Albuterol
Citation
KUMARA, S, Spectrophotometric determination of salbutamol in salbutamol syrup, University of Colombo UC(SCI), 2001: p.