Proceedings of the International scientific and practical conference ―Paris Science and Education Forum‖ (March 2-4, 2026) / Publisher website: www.naukainfo.com. – Paris, France, 2026. - 293 p.

96 Fig. 1 Chemical Structure of Сodeine phosphate hemihydrate The objects of the study were the substance codeine phosphate hemihydrate (codeine phosphate hemihydrate not less than 98.5% and not more than 101.0% calculated on a dry basis (Sanofi Chemie, France), which meets the requirements of the analytical regulatory documentation and Tusoret® Day/Night capsules with active ingredient content of 30 mg (white capsule) and 50 mg (blue capsule) (Pharmaceutical company: MaxMedic Pharma GmbH). Active ingredient: Codeine phosphate hemihydrate (Fig. 1). The active ingredient of Tusoret® day/night capsules is codeine (the term ―codeine‖ refers to the anhydrous base). Day capsule (white): One white capsule contains: Codeine phosphate hemihydrate 40.72 mg (equivalent to 30 mg codeine). Other ingredients: Day capsule (white): Sucrose, Poly(O- ethyl)cellulose, Povidone, Talc, Magnesium stearate, Gelatin, Colorant E 171, Sodium dodecyl sulfate. Night capsule (blue): One blue capsule contains: Codeine phosphate hemihydrate 67.87 mg (equivalent to 50 mg codeine). Other ingredients: Sucrose, Poly(O-ethyl)cellulose, Povidone, Talc, Magnesium stearate, Gelatin, Colorants E 132, E 171, Sodium dodecyl sulfate. (Manufacturer: Saneca Pharmaceuticals a.s.). In Official Monographs for the quantitative determination of codeine phosphate in the substance recommends using the acidimetric titration method in a non-aqueous medium [1, 2]. The analysis of the tablets is carried out similarly after preliminary