Introduction

Cortisone acetate, a steroid, is a drug to reduce tissue inflammation or to suppress the human immune system. This article shows the utility of an X-PressPak C18S column (2.1 mm I.D. x 50 mm L.) with 2 µm particle size for the high speed separation of its drug, and also shows the results to determine whether the performance of the column and chromatography separation exceed those of conventional HPLC.

LC-4000 UHPLC system

Experimental

Chromatographic conditions
Column = X-Press PakC18S (2.1mmI.D.x50mmL.)
Mobile phase = acetonitrile/water (35/65)
Column temperature = 25 ºC
Flow rate = 0.7 mL/min
Detection= UV absorption (254 nm)
Injection volume = 1 µL

Results

Figure 1 shows the separation of a standard mixture of propyl paraben (0.03 mg/mL), butyl paraben (0.03 mg/mL), and cortisone acetate (0.1 mg/mL). The UHPLC separation provides an analysis time 4 times shorter than conventional HPLC while the resolution between the propyl paraben and cortisone acetate was 12.2; the reproducibility for the peak ratio was 0.44%. These results well exceed those of conventional HPLC.

Figure 1. UHPLC chromatogram of a standard mixture (1 = propylparaben (0.03 mg/mL), 2 = butyl paraben (0.03 mg/mL), and 3 = cortisone acetate (0.1 mg/mL))