Introduction

Betamethasone, a steroid, is administered to reduce tissue inflammation or to suppress the human immune system. While several pharmacopoeias say that its quality should be verified by HPLC analysis, there are a lot of demands that it wants to be verified faster than the conventional method (HPLC).

This article shows the utility of an X-PressPak C18S column (2.1 mm I.D. x 50 mm L.) packed with 2 µm diameter packing material for the ultra-high speed separation of the above steroid drug.

LC-4000 UHPLC system

Experimental

Chromatographic conditions
Column: X-PressPak C18S (2.1 mm I.D. x 50 mmL, 2 µm)
Mobile phase: CH₃CN/H₂O (40/60)
Column temperature: 25 ºC
Flow rate: 0.7 mL/min
Detection wavelength: 240 nm
Injection volume: 1 µL

Results

Figure 1 shows the separation of a standard mixture of betamethazone (0.04 mg/mL) and butyl paraben (0.057 mg/mL).  UHPLC system provides an analysis time 9 times shorter  than conventional HPLC while the resolution between the betamethazone and butyl paraben was 18.8; the reproducibility of the peak ratio is 0.44%.

Figure 1  UHPLC chromatogram of the standard mixture (1: betamethazone (0.04 mg/mL), 2: p-oxybenzoate butyl (0.057 mg/mL))