An efficient and accurate reverse phase – high performance liquid chromatographic method was developed and validated for the separation and determination of synthetic food colorant erythrosine E 127. This method was successfully applied for the estimation of erythrosine dye in certain food stuff (cream biscuits, cherry, gems, and candies) and in drug (Ibuprofen tablet - in which erythrosine present as a coating agent). Interaction study was carried out to find the effect of erythrosine on the protein binding of Ibuprofen in Bovine serum albumin. A Phenomenex C 18 Gemini column (150×4.6 mm), 5 μ particle size was used as stationary phase and Mobile phase contained a mixture of 10mM ammonium acetate buffer: Acetonitrile : Methanol in the ratio of (50:25:25v/v/v) at PH 8. The dye was successfully separated out at retention time of 5.6 min, by using isocratic elution technique. Photo diode array detector monitored the wavelength of erythrosine as 529nm and flow rate was selected as 1ml/min. The method was thoroughly validated. Detection limit for erythrosine was found to be 0.1ng/ml, where as limit of quantization of erythrosine was reported as 1ng/ ml. The intra-day precision and inter-day precision were determined as 1.33 % RSD and 0.98 % RSD respectively. The dye E127 was extracted and quantified in various food stuff such as (Cherry - 235μg/ml, Cream biscuits - 316μg/ml, Gems – 177μg/ml, Candies - 36μg/ml) and found that erythrosine content was more in cream biscuits compared to other food stuff. The amount of E127 present in ibuprofen tablet was found to be 5.6 mg/ tablet. A study on protein binding of Ibuprofen by UV spectroscopy and reverse phase high performance liquid chromatography were conducted. The effect of erythrosine on protein binding of Ibuprofen in BSA was carried out and monitored that protein binding of the drug was increased by the effect of dye. Unbound form of the drug was decreased by the effect of dye. Increase in the concentration of drug in BSA, the effect of dye on the drug was found to be more.
