Hydrogel-forming material, premix, and hydrogel formation method

A hydrogel-forming material comprising:

• (i) a disperse phase (A) including 0.2 to 0.5% by mass, relative to a total mass of a formed hydrogel, of a lipid peptide-based gelator consisting of a compound of Formula (1) or a pharmaceutically usable salt thereof, water, and 0.1 to 0.25% by mass, relative to the total mass of the formed hydrogel, of a fatty acid salt, and
• a disperse phase (B) that includes 0.1 to 0.2% by mass, relative to the total mass of the formed hydrogel, of a carboxyvinyl polymer increasing viscosity by neutralization;
• or
• (ii) a disperse phase (A) including 0.3 to 0.5% by mass, relative to a total mass of a formed hydrogel, of a lipid peptide-based gelator consisting of a compound of Formula (1) or a pharmaceutically usable salt thereof, water, and 0.1 to 0.305% by mass, relative to the total mass of the formed hydrogel, of a fatty acid salt, and
• a disperse phase (B) that includes 0.2% by mass, relative to the total mass of the formed hydrogel, of an acrylic acid-alkyl methacrylate copolymer increasing viscosity by neutralization, or 0.1 to 0.5% by mass, relative to the total mass of the formed hydrogel, of a polyacrylic acid increasing viscosity by neutralization:
• where R1 is a C9-23 aliphatic group, R2 is a hydrogen atom or a C1-4 alkyl group that optionally has a C1-2 branched chain, R3 is a —(CH2)n—X group, n is a number of 1 to 4, X is an amino group, a guanidino group, a —CONH2 group, a 5-membered ring optionally containing 1 to 3 nitrogen atom(s), a 6-membered ring optionally containing 1 to 3 nitrogen atom(s), or a condensed heterocycle that contains a 5-membered ring and a 6-membered ring optionally containing 1 to 3 nitrogen atom(s).