Media for nimesulide tablet dissolution: surfactant action

Abstract

Nimesulide is a non-steroidal anti-inflammatory drug, which presents low water-solubility and weak-acid properties. The intrinsic solubility of a drug plays an important role on drug dissolution from a solid dosage form. The development of a dissolution test for poorly hydrophilic drugs can exhibit some difficulties and surfactants are often used to promote drug solubilization. In this work the influences of both sodium laurylsulfate and polysorbate 80 on promotion of nimesulide aqueous solubility were studied. The media were also evaluated regarding their pH, surface tension and critical micelle concentration. All media without surfactant gave very low nimesulide solubility (<60 mg/mL) at pH range of 1.0 to 7.4. The higher solubilities (>;300 mg/mL) were got in phosphate buffer pH 7.4 with polysorbate 80 as additive. As surfactant concentration increases, higher drug saturation values are obtained by micellar solubilization. Dissolution profiles of three nimesulide tablets formulations were conducted employing media with different surfactant concentration by the rotating paddle-method. The results indicated that surfactants in nimesulide dissolution studies should be criteriously chosen in order to avoid poor discriminating medium characteristics.