Electro‐elucidation and quantification of olopatadine hydrochloride in bulk form and eye drops using modification free glassy carbon electrode with its development by different electrolytes and surfactants

Abstract The electro‐oxidation pathway of olopatadine hydrochloride which is used in eye drops as antihistaminic agent was proposed and discussed in detail as the first time using different voltammetry methods at the modification free glassy carbon electrode surface. The oxidation process of olopatadine hydrochloride based on the presence of electro‐active tertiary amine group was irreversible. The dissociation constants were attained by the dependence of peak current and potential on the pH values. Some kinetic parameters were also estimated. Depending on the oxidation of olopatadine hydrochloride in citrate buffer (pH 5.5; 0.1 M) and sodium dodecyl sulfate (3×10 −5 M) as supporting electrolyte and a modifier, respectively, sensitive, simple, accurate and inexpensive a novel square wave voltammetry method was achieved. The method was validated for linearity, precision, accuracy, ruggedness, specificity and stability. Limit of detection of 9×10 −7 M in bulk form was attained. The characterized method was successfully used for routine analysis of olopatadine hydrochloride in pharmaceutical eye drops (Olohistine® and olopalite). No electroactive interferences from the inactive ingredients present in eye drops were noticed. So the proposed method does not necessitate any extraction step preceding the drug analysis. Also, the obtained data of the calibration curve and standard addition methods were compared statistically with a reported spectrophotometrically method showing no differences between them with respect to accuracy and precision, what proved the reproducibility, suitability and reliability of the described voltammetric method for assay of olopatadine hydrochloride in its formulation.