Development and validation of a HPLC and a UV derivative spectrophotometric methods for determination of hydroquinone in gel and cream preparations.

A high performance liquid chromatographic (HPLC) and a ultraviolet derivative spectrophotometric (UVDS) methods were developed and validated for the quantitative determination of hydroquinone (HQ) in gels and creams containing this compound as a unique active principle. Validation parameters such as linearity, precision, accuracy, specificity, limit of detection (LOD) and limit of quantitation (LOQ) were determined. HPLC was carried out by reversed phase technique on a RP-18 column with a mobile phase composed of methanol and water (20:80, v/v). The linearity in the range of 6.0-30.0 microg/mL present a correlation coefficient (r) of 0.9999, calculated by least square method. The LOD and LOQ were 0.08 and 0.26 microg/mL, respectively. Based on the preliminary spectrophotometric profile of HQ, a signal at 302.0 nm of the first derivative spectrum (1D302.0) was found adequate for validation. The linearity between signal 1D302.0 and concentration of HQ in the range of 10.0-26.0 microg/mL in sulfuric acid (0.1N) present a correlation coefficient (r) of 0.9999. The LOD and LOQ were 0.14 and 0.46 microg/mL, respectively. Statistical analysis by t- and F-tests, showed no significant difference at 95% confidence level between the two proposed methods.