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7th International Symposium on ADVANCES IN PHARMACEUTICAL ANALYSIS (APA 2025), Ankara, Turkey, 24 - 27 August 2025, pp.130, (Full Text)
Introduction: Brimonidine tartrate (BT) is a selective α2-adrenergic agonist commonly used in the treatment of ocular
hypertension and glaucoma. This study aimed to develop and validate a simple, fast, and reproducible UV
spectrophotometric method for determining BT concentration in two different media: acetone:water (1:1, v/v) and simulated
tear fluid (STF). The method was validated in line with literature and ICH Q2(R1) guidelines [1-5].
Materials and Methods: BT stock solutions were prepared in both 1:1 acetone:water and Simulated Tear Fluid (STF)
media. λmax was determined as 322 nm in both environments. Calibration standards were prepared at seven concentration
levels (5–60 µg/mL). Method validation included the evaluation of linearity, accuracy, precision, limit of detection (LOD),
and limit of quantification (LOQ). Accuracy and intra-day precision were assessed at 10, 30, and 50 µg/mL. Absorbance
values were measured using a UV-visible spectrophotometer with appropriate blank correction.
Results: In the acetone:water medium, the method showed excellent linearity with the regression equation y = 0.0147x –
0.0068 and a correlation coefficient (R²) of 0.9990. The LOD and LOQ were calculated as 0.98 µg/mL and 2.96 µg/mL,
respectively. The accuracy results at 10, 30, and 50 µg/mL were 99.11% ± 1.04, 99.74% ± 0.35, and 99.87% ± 0.21,
respectively. Precision values were within acceptable limits, with %RSD < 2%.
For the STF medium, the method demonstrated even stronger linearity, with a regression equation y = 0.0108x + 0.0042
and R² = 0.9999. The calculated LOD and LOQ were 1.33 µg/mL and 4.04 µg/mL, respectively. Recovery at the same
concentration levels was found to be 99.66% ± 1.07 (10 µg/mL), 99.58% ± 0.47 (30 µg/mL), and 99.57% ± 1.30 (50 µg/mL),
indicating high accuracy. Precision results were also consistent with ICH criteria, with %RSD below 2% at all levels.
Conclusion: The developed UV spectrophotometric method is sensitive, accurate, and reproducible for the quantification
of brimonidine tartrate in both acetone:water and simulated tear fluid media. The method demonstrates excellent linearity
and precision, with recovery rates near 100% and low %RSD values. These findings confirm the suitability of this validated
method for routine analysis and in vitro release studies of BT.
Acknowledgements
This study was supported by Scientific Research Coordination Unit of Anadolu University under the project number TYL-
2025-2924 (Project ID: 2924).