Spectrophotometric Determination of Benzalkonium Chloride using Sulfonphthaleins

A highly sensitive method for the quantitative determination of Benzalkonium chloride (BKC), in its pure form and pharmaceutical formulations, is described. The method involves four spectrophotometric ways for the determination of BKC via forming ionassociates with bromocresol green (BCG), bromophenol blue (BPB), bromothymol blue (BTB), and xylenol orange (XO). The study involves characterization of the ion-pairs formed between the BKC and the above-mentioned reagents Using UV-Visible and IR spectroscopy. In order to optimize the reaction conditions, the effects of pH, the quantity of reagent, time, and extracting solvent were studied. Statistical student’s t-test and F test showed insignificant systematic error between proposed and official methods. The antibacterial disinfectant Zora C Lozenges contains 0.01 mg Benzalkonium chloride, 1 mg Benzocaine, and 50 mg Vitamin C. as the active substance was analyzed at pH 8.5. The strategy was validated for linearity range, precision, accuracy, specificity, and limits of detection (LOD) and quantification (LOQ). Beer's law is obeyed over a wide concentration range (up to 145 ?g/mL in case of BCG method). LOD and LOQ values reached 2.38 and 7.2 ?g/mL, respectively, upon using BCG. The relative standard deviation (%RSD) was ?1.33% while correlation coefficient values (r) were ? 0.998. High molar absorptivity values and low values of Sandell's sensitivity were calculated indicating that the proposed methods are highly sensitive. Applying the validated methods to the analysis of BKC in antibacterial disinfectant Zora C Lozenges revealed that the drug was successfully resolved from the pharmaceutical formulation with recoveries ?95.5%.