A method for solubilizing 5-amino-2,3-dihydro-1,4-phthalazinedione, comprising the following steps: a) Providing 5-amino-2,3-dihydro-1,4-phthalazinedione in the overall range of 0.1 % to 25 % per weight at room temperature and a pressure of 0.2 bar to 1 bar; b) Adding in any sequence the solubilization agents of at least one phosphatidylcholine in the overall range of 20 % to 80 % per weight, at least one medium-chained triglyceride in the overall range of 10 % to 70 % per weight, at least one lysophosphatidylcholine in the overall range of 1 % to 15 % per weight, at least one C 2 to C 4 alcohol in the overall range of 1 % to 20 % per weight, and at least one of glyceryl stearate and/or a saturated or unsaturated C 14 to C 20 fatty acid in the overall range of 0.5 % to 10 % per weight, respectively, wherein the relative weight percentages of all ingredients add up to 100 % and all solubilization agents are independently from one another a food additive and/or a pharmaceutically acceptable excipient; c) Cautiously heating the resulting mixture by continuously increasing the temperature with a continuous temperature increment of 0.5°C/min - 3°C/min over a period of 20 - 60 minutes; d) Stopping the temperature increase in a temperature range of 30°C to 125°C as soon as a clear solution is reached; and e) Letting the resulting solubilisate cool down to room temperature. a) Providing 5-amino-2,3-dihydro-1,4-phthalazinedione in the overall range of 0.1 % to 25 % per weight at room temperature and a pressure of 0.2 bar to 1 bar; b) Adding in any sequence the solubilization agents of at least one phosphatidylcholine in the overall range of 20 % to 80 % per weight, at least one medium-chained triglyceride in the overall range of 10 % to 70 % per weight, at least one lysophosphatidylcholine in the overall range of 1 % to 15 % per weight, at least one C 2 to C 4 alcohol in the overall range of 1 % to 20 % per weight, and at least one of glyceryl stearate and/or a saturated or unsaturated C 14 to C 20 fatty acid in the overall range of 0.5 % to 10 % per weight, respectively, wherein the relative weight percentages of all ingredients add up to 100 % and all solubilization agents are independently from one another a food additive and/or a pharmaceutically acceptable excipient; at least one medium-chained triglyceride in the overall range of 10 % to 70 % per weight, at least one lysophosphatidylcholine in the overall range of 1 % to 15 % per weight, at least one C 2 to C 4 alcohol in the overall range of 1 % to 20 % per weight, and at least one of glyceryl stearate and/or a saturated or unsaturated C 14 to C 20 fatty acid in the overall range of 0.5 % to 10 % per weight, respectively, wherein the relative weight percentages of all ingredients add up to 100 % and all solubilization agents are independently from one another a food additive and/or a pharmaceutically acceptable excipient; c) Cautiously heating the resulting mixture by continuously increasing the temperature with a continuous temperature increment of 0.5°C/min - 3°C/min over a period of 20 - 60 minutes; d) Stopping the temperature increase in a temperature range of 30°C to 125°C as soon as a clear solution is reached; and e) Letting the resulting solubilisate cool down to room temperature.