Which statement about co-solvents, surfactants, and solid dispersions is true?

• A. Co-solvents decrease solubility
• B. Surfactants degrade wettability
• C. Solid dispersions stabilize the drug in an amorphous, higher-energy form
• D. Lipid-based formulations hinder solubilization

Answer: (C)

The thing being tested is how formulation strategies like co-solvents, surfactants, and solid dispersions affect solubility and dissolution of drugs. Co-solvents increase solubility by changing the solvent environment and boosting the drug’s solvating power, so they do not decrease solubility. Surfactants improve wettability and lower interfacial tension between the drug and aqueous media; they can also form micelles that solubilize drug, which helps dissolution rather than harming wettability. Solid dispersions work by dispersing the drug in a polymeric carrier in an amorphous form, which has higher free energy than the crystalline form. This disrupts crystal lattice energy barriers and enhances dissolution, often increasing apparent solubility. Because of that, the statement that solid dispersions stabilize the drug in an amorphous, higher-energy form is true.