Development of approaches to the analysis of elemental impurities in titanium dioxide (arsenic definition)

Relevance. Titanium dioxide plays an important role at all stages of the drug’s life cycle: from protecting active ingredients to improving the quality of care for patients when taking the drug. Despite the ongoing debate about its safe use, it remains one of the most sought-after adjuvants in the pharmaceutical industry today. An important factor in the safety of any component of the drug is the control of its content of elemental impurities. Since for titanium dioxide the pharmaceutical requirements for the content of elemental impurities differ significantly, it was advisable to develop approaches to their definition under the most stringent regulations.

Research objective. This work is devoted to the development of approaches to the analysis and further validation of the method of determination of arsenic in the substance titanium dioxide at the level of 1 ppm.

Material and methods. The basis of the used method was the conditions of the monograph USP «Titanium Dioxide», where a solution of silver diethyldithiocarbatum is used as an arsenic reagent. All the reagents and materials used were pharmacopoeic. A sample of titanium dioxide, produced by Venator Germany GmbH, Germany, was used as the research object. The validation of the methodology was carried out in accordance with the requirements of the State Pharmacopoeia of the Russian Federation on the following characteristics: specificity, linearity, LOQ, correctness, repeatability, intralaboratory precision and range of the technique.

Results. The application of the technique using diethyldithiocarbamate silver as reagent to determine arsenic at 1 ppm is shown. At the same time, the validation evaluation of the methodology showed that the obtained results met the criteria of acceptability for all the studied characteristics.

Conclusions. Due to its properties, the substance titanium dioxide remains in demand in the pharmaceutical industry as a adjuvant. In this case, one of the factors of its safe use is the control of its content of elemental impurities.

Due to the wide variety of pharmacopoeic requirements for the content of elemental impurities in the substance titanium dioxide. This study demonstrated the applicability of the technique using diethyldithiocarbamate silver as a reagent to determine arsenic at the most stringent of its standards (1 ppm). The validation of the technique proved that it was possible to quantify the arsenic content of titanium dioxide in the range from 50% (LOQ) to 150% of the specification level.