Solubility of rofecoxib in the presence of methanol, ethanol, and sodium lauryl sulfate at (298.15, 303.15, and 308.15) K

The poorly water-soluble anti-inflammatory rofecoxib is studied for solubility enhancement with the help of cosolvents such as methanol and ethanol as well as an anionic surfactant sodium lauryl sulfate (SLS) in water. The analysis of the drug is carried out by UV spectral measurements at lambda(max) of 285 nm. The effect of mass fraction of cosolvents and surfactant on the solubility of the drug is studied at (298.15, 303.15, and 308.15) K. Increased solubility of rofecoxib was observed by increasing the mass fraction of methanol and SLS in water at all the temperatures. In the case of the water + ethanol mixture, the solubility of rofecoxib was somewhat unusual; that is, solubility increased with increasing mass fraction of ethanol up to 80%, but solubility decreased in pure ethanol at all the temperatures. Experimental solubility data of rofecoxib were correlated with those calculated by a log-linear equation.