Hydrogel patch including additive solution adjustable for its syneresis pattern and method of manufacturing the composition

A method for preparing a hydrogel patch containing a filling solution for controlling a syneresis pattern, the method comprising steps of:

• separately stirring a phase A consisting of a crosslinking agent and purified water, a phase B consisting of an organic polymer and a polyhydric alcohol, and a phase C consisting of a pH adjusting agent and purified water, and then sequentially adding the phase B and the phase C to the phase A, thereby preparing a hydrogel;
• separately stirring a phase D consisting of a humectant and purified water, a phase E consisting of a thickener and a polyhydric alcohol, and a phase F consisting of a pH adjusting agent and purified water, and then sequentially adding the phase E and the phase F to the phase D, thereby preparing a filling solution;
• and
• filling the hydrogel with the filling solution,
• wherein:
• the organic polymer comprises carrageenan and carob gum;
• the crosslinking agent, the carrageenan, the carob gum and the polyhydric alcohol are contained in amounts of more than 0% w/w and less than or equal to 5.0% w/w, 0.1 to 5.0% w/w, more than 0% w/w and less than or equal to 4.0% w/w, and 15.0 to 30.0% w/w, respectively, based on the total weight of the hydrogel;
• the thickener is contained in an amount of more than 0% w/w and less than or equal to 5.0% w/w based on the total weight of the hydrogel;
• and
• the thickener of the phase E reduces a difference in osmotic pressure between the filling solution and the hydrogel by reducing a viscosity of the filling solution.