The Effect of Enzymes and Sodium Lauryl Sulfate on the Surface Tension of Dissolution Media: Toward Understanding the Solubility and Dissolution of Carvedilol

The objective of this work was to study the effect of the physiologically relevant enzymes pepsin, pancreatin, and the synthetic surfactant sodium lauryl sulfate (SLS) on the surface tension of the dissolution media and the solubility and dissolution of the weakly basic drug carvedilol. Compendial dissolution media and buffer solutions that simulate the gastrointestinal fluid, prepared with and without the addition of SLS, were used in this study. The surface tension of the dissolution media; critical micelle concentration (CMC) of SLS in buffer solutions; and size, polydispersity index, and zeta potential of SLS micelles loading carvedilol were determined. The solubility and dissolution of carvedilol were investigated and compared with those of the corresponding media prepared without the addition of pepsin, pancreatin, and SLS. Results showed that the addition of pepsin, pancreatin, and SLS lowered the surface tension of the dissolution media to 54.8, 55.7, and ~ 30 mN/m, respectively. The solubility of carvedilol was significantly enhanced with pepsin and SLS; however, no significant difference was found with pancreatin. The dissolution rate of carvedilol was fast in simulated gastric fluid with and without pepsin. The dissolution was further enhanced in media with pancreatin and SLS. The dissolution data were corroborated with the molar micellar solubilization (X) of SLS, ranging between 0.02 and 3.09. Understanding the effect of pepsin, pancreatin, and SLS on the surface tension of the dissolution media and the solubility and dissolution of poorly soluble drugs can improve our knowledge of the performance of these drugs in vivo.