A highly sensitive spectrofluorimetric method for the determination of bilastine in its pharmaceutical preparations and biological fluids.

Allergic rhinitis and urticaria are extremely prevalent among all age groups. From the clinical experience, usually, an essential second-generation non-sedating H-antihistaminic drug, such as bilastine is given to relieve allergic symptoms. Bilastine is preferred to be used instead of oral corticosteroids and first -generation sedating H-antihistaminics to avoid their side effects. A highly sensitive and simple spectrofluorometric method was developed and validated for the determination of bilastine in its dosage forms and biological fluids. The quantum yield was calculated and was found to be as high as 0.48. Aqueous water solution of bilastine gives high native fluorescence emission at 298 nm after excitation at 272 nm. A rectilinear calibration plot was obtained over the concentration range of 1.0-50.0 ng mL. The limits of quantitation and detection were 1.0 and 0.33 ng mL, respectively. The parameters influencing its spectrofluorimetric behavior, viz, type of solvent, pH and organized media were studied. The proposed method was successfully applied for the determination of the drug in pharmaceutical dosage form and the results obtained were in good agreement with those of given by reported method. The high sensitivity of the proposed method enabled the estimation of the drug in biological matrices, including human plasma and urine samples after simple protein precipitation, and the results obtained were satisfactory.