Hyaluronic acid (or hyaluronan) is a polysaccharide with therapeutic applications in dentistry due to its lubricating, anti-inflammatory, and antibacterial properties. This study evaluates the diffusion, conductivity, and viscosity of the sodium salt of HyH (that is, NaHy) with different molecular weights (124 kDa, 245 kDa, and 1800 kDa) in artificial saliva at pH 2.3, 4, 5, 6.8, and 8. Using the Taylor dispersion technique at 298.15 K, diffusion coefficients were determined and analyzed based on Fick’s second law equation. Results showed that NaHy diffusion was higher at acidic pH, particularly at pH 2.3, and decreased at pH 8, likely due to structural compaction in acidic conditions and expansion in alkaline media. The higher molecular weight of this polysaccharide exhibited greater diffusion and conductivity, suggesting an extended conformation that enhances mobility. These findings indicate that both pH and molecular weight significantly influence NaHy transport properties. Optimizing these parameters may enhance HA’s bioavailability and effectiveness in topical oral applications, improving its therapeutic potential in treating periodontal and oral conditions.