ACKNOWLEDGMENTS The definitely authors are thankful to Alpha Laboratories, Baroda, Gujarat, India for providing gift samples of METO and OLME for research. The authors are highly thankful to APMC College of Pharmaceutical Education and Research, Himmatnagar, Gujarat, India, for providing all the facilities to carry out the work. Footnotes Source of Support: Nil Conflict of Interest: None declared.
Diacerein chemically is 4,5-bis(acetyloxy)-9,10-dioxo-2-anthracene carboxylic acid.[1�C2] It is a selective inhibitor of interleukin-1 having a protective effect on granuloma-induced cartilage breakdown by a reduction in the concentrations of proinflammatory cytokines. It is used in the symptomatic treatment of osteoarthritis.

[3] The literature survey revealed many analytical methods includes UV-spectroscopic methods,[4�C7] RP-HPLC,[8�C12] and HPTLC methods[13] for the estimation of diacerein in bulk, pharmaceutical formulation, and in biological samples. The spectrophotometric methods available for diacerein in literature reveal the use of dimethyl acetamide (DMA)[14] and dimethyl sulfoxide (DMSO)[15] to solubilize diacerein. Drawbacks of organic solvents include their higher cost, toxicity, and pollution. In addition, diacerein is poorly soluble in water. Therefore, hydrotropic solution may be a suitable alternative to exclude the use of organic solvents. Special systems are required to solubilize poorly water-soluble drugs. Hydrotropy is one of such techniques. Hydrotropy may be defined as a phenomenon in which the water solubility of poorly water-soluble compounds may be increased several folds by the use of diverse groups of hydrophilic solutes called hydrotropes.

[16] Hydrotropes commonly used includes sodium benzoate, sodium acetate, sodium salicylate, nicotinamide, urea, trisodium citrate, sodium ascorbate, piperazine, caffeine, potassium citrate, etc.[17] Hydrotropic agents have been observed to enhance the solubility of various substances in water.[18] The mixed hydrotropic solubilization process is used to increase the solubility of poorly water-soluble drugs by using blends of hydrotropic agents. There was a miraculous synergistic effect on enhancement in solubility of a poorly water-soluble drug by mixing two hydrotropic agents.[19] In the literature, several methods were reported for estimation of poorly water-soluble drugs using hydrotropic solubilizing agents.

[20�C22] Therefore, it was thought useful to utilize this hydrotropic solution to extract out the drug from fine powder of tablets to carry out spectrophotometric estimation. The objective Dacomitinib of the present investigation is to develop simple, precise, and accurate UV-spectrophotometric and first-order derivative methods for determination of diacerein in bulk and in the capsule dosage form using hydrotropic solubilizing agents. The developed methods were validated as per the ICH guidelines.