Dexamethasone HPLC Assay and Impurity Profiling Methods Following United States Pharmacopeia Monograph Guidelines Using a Titan C18 Column and UV Detection

Introduction

A simple, precise and sensitive Reverse-Phase High Pressure Liquid Chromatography gradient method was adapted for traceability, homogeneity and total chromatographic analysis of Dexamethasone. The given experimental conditions follow the USP43-NF38 monograph method for Dexamethasone Assay and Organic Impurity Profiling. Dexamethasone, Betamethasone, Dexamethasone acetate and Desoximetasone were baseline resolved within 20 minutes using a Titan C18 UHPLC column (2.1 x 100 mm, 1.9 µm). This column has the same packing, length and ID, but where the packing is bound to a slightly larger average particle size (1.7 µm) referenced in the monograph. The method was validated following the guidelines in USP General Chapters <621>, <1225>, and <1226>. Lower sample concentrations were used, but compensated by a larger injection volume (to maintain mass on column) to improve reproducibility. The chromatographic separation was achieved using a mixture of 3.4 g/L monobasic potassium phosphate solution (pH 3.0) and acetonitrile as the mobile phase with gradient elution and UV detection at 240 nm. Much shorter relative retention time (RRT) was seen for Dexamethasone acetate and Desoximetasone, but with excellent chromatographic resolution (Rs > 10) for both compounds. Under the applied conditions, system suitability requirements are met, and the method demonstrates good selectivity, reproducibility, sensitivity and accuracy.

Dexamethasone, Betamethasone, Dexamethasone Acetate, Desoxiametasone chemical structure

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Blank Solution

Standard solution

Standard solution

System Suitability Solution

System Suitability Solution

Dexamethasone (Test Solution)

Dexamethasone (Test Solution)

Reference Solution

Reference Solution
Table 1.Chromatographic Data (System Suitability Solution)
Table 2.Chromatographic Data (Reference solution)
Table 3.Repeatability (Reference solution)
Materials
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