Photometric determination of succinic acid in liquid preparations

Introduction. Succinic acid is a substance having various types of biological activity and is part of many combination preparations used in medical and veterinary practice. Objective: to develop a procedure for the determination of succinic acid that would be distinguished by selectivity, sufficient sensitivity, and simplicity of instrumentation. Material and methods. The investigation objects were succinic acid, a cytoflavin solution for injections, and Dorogov's antiseptic stimulator 2 (DAS-2)-based solution. Photometry in the visible region of the spectrum based on the conversion of the analyte into stained dihydronaphthazarin is considered as an analysis method. Results. The investigators proposed a modified version of obtaining 5,8-dioxy-2,3-dihydro-1,4-naphthaquinone (dihydronaphthazarin) (a stained analytical form) from succinic acid through its treatment with excess hydroquinone and concentrated (p=1.830-1.832 g/cm3) sulfuric acid for 30 minutes sequentially at temperatures of 105-110 and 145°С. The stained product is able to be extracted with toluene. The spectrum of the product in the toluene medium is characterized by the presence of a vibrational band with a maximum at 520 nm. The considered chromogenic reaction in the proposed modification proceeds quantitatively. The linear relationship between the reference succinic acid concentration in the photometric solution and the optical density corresponds to the range of 25-250 |ig/ml. Conclusion. Procedures were developed for the photometric determination of succinic acid in the cytoflavin solution for injection and in DAS-2-based solution. The validation characteristics of the procedure showed the agreement of their criteria for linearity, selectivity, correctness, and precision.

succinic acid, liquid preparations, photometric determination, validation