Sodium hyaluronate solutions are used as artificial tears that moisturize and regenerate the eye. Sodium hyaluronate as a polymer composed of repeating units of the disaccharide D-glucuronic acid and N-acetyl-Dglucosamine also exhibits mucoadhesive properties, which means that it interacts with mucin, a part of the mucous membrane on the surface of the eye. By creating these interactions, the retention of the solution on the mucous membrane is prolonged. The purpose of this paper is to examine the influence of factors that can increase retention on the mucous membrane. It was tested how the molecular weight and mass fraction of sodium hyaluronate in the solution, and osmolality of the solution affect the mucoadhesion of the solutions. Also, the rheological properties and characteristics (viscosity, pH, osmolality and surface tension) of solutions with different intrinsic viscosities of sodium hyaluronate 0.6 m3/kg, 1.7 m3/kg, and 2.3 m3/kg (respectively molecular weight ≈250 kDa, ≈980 kDa and ≈1420 kDa) were tested in three mass fractions: 0.21%; 0.4% and 0.6%, in hypotonic, isotonic, and hypertonic conditions. With an increase in the mass fraction of sodium hyaluronate, as well as with an increase in its molecular weight, the viscosity of the solution increases, while an increase in the osmolality of the solution decreases the viscosity, regardless of the molecular weight and mass fraction of sodium hyaluronate. The stability of all solutions was also tested after storage at temperature 50 °C for three months. In all cases, there was a decrease in the viscosity of the solutions, while there were no significant changes in other parameters. Using rheological measurements on a rheometer, relative rheological synergism was determined with porcine gastric mucin, which indicates whether there is an interaction between the solution and the mucin. Isotonic solutions of sodium hyaluronate with intrinsic viscosities of 1.7 m3/kg and 2.3 m3/kg in a mass fraction of 0.4% showed interaction with mucin, while the solution with sodium hyaluronate with the lowest intrinsic viscosity of 0.6 m3/kg did not show interaction. It is important to note that this solution was the only one that showed Newtonian rheological behavior. The increase in the osmolality of the solution showed an increase in the interaction with mucin as well as an increase in the mass fraction of sodium hyaluronate. This influence was tested on solutions with sodium hyaluronate with an intrinsic viscosity of 1.7 m3/kg. The interaction with mucin increases with a higher mass fraction of salt in the solution (higher osmolality) and an increase in the mass fraction of sodium hyaluronate, while the obtained results do not show a proportional relationship between the interaction with mucin and the molecular weight of sodium hyaluronate. The above should be confirmed by including more sodium hyaluronates in a wider range of molecular masses (intrinsic viscosity) in the test, and by using other methods for determining mucoadhesion.