A Colorimetric Method to Measure the Amount of Hydroquinone in Liposomal Formulations

A method for determination of concentration of solute depended on its chemical properties, degree of dilution and matrix that takes it is developed. Formulation of liposomal hydroquinone, a drug delivery system, is developed to increase its efficacy. In this study, a colorimetric method based on the method of diphenyl picryl hydrazyl (DPPH) reduction was used to measure the concentration of hydroquinone in the liposomal matrix. Hydroquinone is an ingredient with antioxidant activity that is able to reduce DPPH molecules. the samples were dissolved in methanol for testing, and after an hour of mixing with DPPH, the absorption intensity of each sample was measured at the wavelength of 516 nm, then validation parameters such as linearity and range, precision, accuracy, specificity, LOQ and LOD were measured. This method can be used to determine the concentration of liposomal hydroquinone samples in the concentration range of 0.5 to 2 μg/ml, with a regression rate of 0.999, precision 2.1% for intraday and 2.8% for inter-day, recovery 96.2% and 100.8% for 80% and 120% main concentration, respectably. LOQ 0.149 μg/ml and LOD 0.04 μg/ml were obtained. This method is precise, accurate specific and linear for determination of hydroquinone in liposomal matrix.