Which of the following factors are involved in media selection for dissolution testing?

• A. Temperature only
• B. Color of the solvent
• C. pH, ionic strength, and presence of surfactants to simulate GI fluids
• D. Gas content

Answer: (C)

In dissolution testing, the medium is chosen to resemble the environment the drug encounters in the GI tract, because solubility and dissolution rate depend on that environment. The key factors to consider are pH, ionic strength, and the presence of surfactants. pH influences how an ionizable drug dissolves since many drugs change their ionization state with pH, altering solubility; you’d select a medium that mirrors gastric or intestinal conditions (or use specific simulated fluids like SGF, SIF, FaSSIF, or FeSSIF) to reflect where dissolution will occur. Ionic strength matters because it affects solubility and ion pairing, which can change how readily the drug dissolves. Surfactants simulate the role of bile salts and other surface-active components in the GI tract, helping to solubilize poorly soluble drugs via micellar or wettability-enhancing effects. Together, these elements create a realistic medium that yields meaningful dissolution data and better IVIVC.

Temperature control is also important in practice, but it’s a separate experimental parameter (usually 37°C) rather than a property of the dissolution medium itself. Color of the solvent and gas content aren’t relevant factors for media selection in dissolution testing.