Process for manufacturing an injection agent and injection agent obtainable by this process

A process for manufacturing an injection agent comprising a viscoelastic liquid including water, a first poloxamer, and a second poloxamer, the process comprising:

• a) producing a first injection agent by mixing a specific amount of the water with a first amount of the first poloxamer, wherein a concentration of the first poloxamer in the first injection agent is in an amount between 14 wt % and 17 wt %, and with a second amount of the second poloxamer, wherein a concentration of the second poloxamer in the first injection agent is in an amount between 0.5 wt % and 1 wt %, thereby obtaining a predetermined amount of the first injection agent;
• b) determining a viscosity of the first injection agent obtained in step a) at different temperatures at a predetermined shear rate of 95 reciprocal seconds (s−1) to obtain a present viscosity-over-temperature-curve;
• c) verifying if a maximum viscosity of the present viscosity-over-temperature-curve lays in a predetermined specific temperature range and in a predetermined maximum viscosity range depending on the predetermined shear rate, wherein the predetermined specific temperature range comprises a range between a lower temperature (T1) of 36° C. and an upper temperature (T2) of 38° C., and wherein the predetermined maximum viscosity range comprises another range between a lower maximum viscosity (V1) of 1.8 Pascal-second (Pa·s) and an upper maximum viscosity (V2) of 1.9 Pa·s;
• d) producing a new injection agent by changing at least the first amount of the first poloxamer, the second amount of the second poloxamer, or a combination thereof based on the first injection agent obtained in step a), if the maximum viscosity of the present viscosity-over-temperature-curve obtained in step b) lays outside of the predetermined specific temperature range and the predetermined maximum viscosity range;
• and
• e) repeating steps b) and c) and, when necessary, step d) until it is determined in step c) that the maximum viscosity of the present viscosity-over-temperature-curve lays in the predetermined specific temperature range and in the predetermined maximum viscosity range;
• and
• wherein in step d), (i) the first amount of the first poloxamer is increased if the maximum viscosity of the present viscosity-over-temperature-curve is below the predetermined maximum viscosity range in the predetermined specific temperature range or the first amount of the first poloxamer is reduced if the maximum viscosity of the present viscosity-over-temperature-curve is above the predetermined maximum viscosity range in the predetermined specific temperature range, (ii) the second amount of the second poloxamer is increased if the temperature range at which the maximum viscosity of the present viscosity-over-temperature-curve is determined, is below the predetermined specific temperature range or the second amount of the second poloxamer is reduced if the temperature range at which the maximum viscosity of the present viscosity-over-temperature-curve is determined is above the predetermined specific temperature range, or (iii) a combination of (i) and (ii).