The effects of surfactants on the dissolution profiles of poorly water-soluble acidic drugs

The effects of types of surfactants on the solubilization and dissolution of poorly soluble acidic drugs were compared to identify the most suitable surfactant for conducting an acidic drug dissolution test. Cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, sodium lauryl sulfate (SLS) as an anionic surfactant, and polysorbate 80 as a non-ionic surfactant were used in the study. And, mefenamic acid, nimesulide, and ibuprofen were selected as model drugs. The dissolution rates of these acidic drugs were substantially enhanced in medium containing CTAB. Electrostatic interactions between acidic drugs and cationic surfactants were confirmed by measuring UV spectra of each drug. Solubility of drugs in various media and the partition coefficients of drugs into micelles were found to depend on drug characteristics. For acidic drugs, the ability of media containing a cationic surfactant to discriminate rates of dissolution of acidic drugs seemed to be greater than that of media containing other surfactant types.