ObjectiveTo develop two safe, novel, eco-friendly, sensitive and accurate UV – spectrophotometric methods by applying hydrotropic solubilization phenomenon for the estimation of diacerein in capsule dosage form. MethodPreliminary solubility studies of drug, selection of hydrotrope, UV spectral studies, Optimization of hydrotrope, direct spectrophotometric and derivative method development, validation of proposed methods were performed as per ICH guidelines. Application of developed method on marketed formulation. ResultsThe aqueous solubility of diacerein was increased by more than 270 folds by using 8 M urea solution as hydrotropic agent in comparison to solubility in distilled water. The sample obeys the Beer's law in the concentration range of 1 – 15 μg/mL & 2 – 45 μg/mL with correlation coefficient of 0.9994 & 0.9997 for each method respectively. The accuracy was proved by recovery studies with mean recovery of 99.80% and 99.08% for each method respectively. Intermediate & repeatability precisions were performed on two consecutive days and analyst to analyst variation with %RSD obtained less than 2%. The LOD & LOQ results intricate the sensitivity of both the methods. ConclusionsIt can be concluded that by applying the hydrotropic solubilization technique for estimating hydrophobic drugs provides a simple, sensitive, cheap & safe estimation. Moreover detrimental health effects & hazardous effects on our environment by using organic solvents can be overcome. Proposed method is less time consuming with two steps of analysis for estimating drug content in formulation.