For dissolving N-acetylcysteine (NAC) among the options of distilled water, culture medium, and phosphate-buffered saline (PBS), the most suitable solvent is generally distilled water or PBS, depending on the experimental context:

• Distilled water is the most common and effective solvent for NAC because NAC is highly soluble in water due to its hydrophilic nature. This makes distilled water ideal for preparing NAC stock solutions for many biochemical and clinical applications.
• PBS (Phosphate-Buffered Saline) is also a suitable solvent for NAC, especially in biological or cell culture experiments, as it maintains physiological pH and osmolarity. NAC remains soluble in PBS, and this buffer can help preserve the stability of NAC and maintain a biological environment compatible with cells or tissues.
• Culture medium can be used to dissolve NAC when working directly with cells in vitro. However, NAC solubility and stability may vary depending on the medium composition (presence of proteins, salts, and pH). It is often preferable to prepare NAC stock solutions in water or PBS and then dilute into culture medium to avoid interactions or precipitation.

In summary, for most laboratory and clinical uses, distilled water or PBS are recommended solvents for NAC due to their compatibility, solubility, and ability to maintain NAC stability. Culture medium can be used but is less ideal for initial dissolution