Wioletta Parys, Agata Wojdyła, Alina Pyka-Pająk

TLC combined with densitometry for the determination of trazodone in tablets

2025-12-01

Subject of research. Trazodone is an antidepressant that belongs to the class of drugs known as serotonin antagonists and reuptake inhibitors (SARIs). To date, thin-layer chromatography (TLC) combined with densitometry has been used to determine trazodone in human blood serum in only two scientific publications. However, there are no reports on the use of this method for the analysis of trazodone in pharmaceutical preparations.

Aim. Development of optimal conditions for quantitative determination of trazodone in Trazodone Neuraxpharm tablets using a simple, rapid, and effective TLC-densitometric method.

Material and methods. The analyses were carried out on TLC plates coated with silica gel 60F₂₅₄ using a mobile phase consisting of toluene, acetone, ethanol, and ammonia in a volume ratio of 9 : 5 : 1 : 0.5. The developed method was fully validated.

Results. The linearity of the method was in the range of 0.2 to 1.0 µg/spot. The accuracy determined by recovery and expressed as the coefficient of variation ranged from 0.94% to 1.07%. Intra-day and inter-day precision ranged from 0.73% to 1.94% and from 1.49% to 2.58%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for trazodone were 0.009 and 0.027 µg/spot, respectively. The actual content of trazodone in Trazodone Neuraxpharm tablets was 49.0 mg, which corresponds to 99.0% of the declared amount of the active substance (50 mg), and complies with pharmacopoeial requirements.

Conclusions. The developed TLC-densitometric method used for the quantitative determination of trazodone in Trazodone Neuraxpharm tablets is selective, accurate, and precise. The proposed TLC method combined with densitometry can be used for routine quality control of trazodone in pharmaceutical preparations (tablets). The TLC method combined with densitometry provides a more affordable alternative compared to high‑performance liquid chromatography (HPLC), which is recommended by the United States Pharmacopeia for quantitative analyses. The proposed method can also be applied in laboratories that do not have access to HPLC.

Keywords: TLC, densitometry, trazodone, SARI, depression.

© Farm Pol, 2025, 81(3): 149–156