rabea khoshneviszadeh - biochemistry and biology department, science faculty, pishva-varamin branch of islamic azad university
Bibi Sedigheh Fazly Bazzaz - Biotechnology Research Center, School of pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
Omid Rajabi - Department of Drug and Food Control, School of Pharmacy, Mashhad University of Medical Sciences.Targetted Drug Delivery Research Centre, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran

A method of determination of concentration of solute depended to its chemical properties, degree of dilution and matrix that takes it. Formulation of liposomal hydroquinone, a drug delivery system, is developed to increase efficacy treatment. Challenge of determination of low concentrations of hydroquinone in liposomal complex matrix by simple method was done successfully. 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 a 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 hydroquinone liposomal samples in the concentration range 0.5–2 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 precision, accuracy, specificity and linear to determination hydroquinone in liposomal matrix.

liposome, hydroquinone, DPPH, Validation, colorimetric method, determination of concentration