Spectrophotometric Simultaneous Determination of Salbutamol Sulfate and Ketotifen Fumarate in Combined Tablet Dosage Form by First-Order Derivative Spectroscopy Method

Salbutamol sulfate and ketotifen fumarate are used in combination for the treatment of asthma. The present work deals with method development for simultaneous estimation of salbutamol sulfate and ketotifen fumarate in two-component tablet formulation by first-order derivative spectroscopy. For determination of sampling wavelength, 10？μg/mL of each of salbutamol and ketotifen was scanned in 200–400？nm ranges and sampling wavelengths were found to be 257？nm for salbutamol and 278？nm for ketotifen in first-order derivative spectroscopy. In this method, linearity was observed in the ranges of 5–45？μg/mL for salbutamol and 5–35？μg/mL for ketotifen. The % recovery was within the range between 98 and 102%, and % relative standard deviation for precision and accuracy of the method was found to be less than 2%. The method is validated as per international conference on harmonization guidelines. The method can be successfully applied for the simultaneous analysis of both drugs in pharmaceutical dosage forms. 1. Introduction Salbutamol sulfate, chemically known as (rs)-1-(4-hydroxy-3-hydroxymethylphenyl)-2-(tert-butylamino) ethanol sulfate (Figure 1), is beta-adrenoceptor agonist used as an antiasthmatic drug [1]. It is official in Indian pharmacopoeia and British pharmacopoeia. It is estimated by acid-base titration method as per Indian pharmacopoeia and British pharmacopoeia [1, 2]. The literature review reveals that HPLC [3–5] and UV spectrophotometric methods [6–8] have been reported for estimation of salbutamol sulfate in pharmaceutical dosage forms. Figure 1: Chemical structure of salbutamol sulfate. Ketotifen fumarate, chemically known as 4-(1-methyl-4-piperidylidene)-4h-benzo [4, 5] cyclohepta [1, 2-b] thiophen-10(9h)-one hydrogen fumarate (Figure 2), is cycloheptathiophene blocker of histamine h-1 receptors used as an antiallergic and an antiasthmatic drug [9]. It is not official in Indian pharmacopoeia, British pharmacopoeia, United States pharmacopoeia, and European pharmacopoeia. The literature review reveals that HPLC [10, 11] and UV spectrophotometric methods [12, 13] have been reported for estimation of ketotifen fumarate in pharmaceutical dosage forms. Figure 2: Chemical structure of ketotifen fumarate. The salbutamol sulfate and ketotifen fumarate mixture is not yet official in any pharmacopoeia. As per literature, no analytical method could be traced for the analysis of salbutamol sulfate and ketotifen fumarate combination in pharmaceutical dosage forms. Therefore, simple, rapid, and reliable method for simultaneous estimation of these drugs in