High Speed Analysis of Paracetamol and its Process Impurities

September 1, 2008
Silvia Marten

The Application Notebook

The Application Notebook, The Application Notebook-09-01-2008, Volume 0, Issue 0

Paracetamol is a major ingredient in numerous medications due to its analgesic and antipyretic properties. During its synthesis (Figure 1), a total of ten process-related impurities are observed. Several HPLC applications have been developed for the monitoring of these impurities (1, 2), including the European Pharmacopoeia which has adopted an isocratic HPLC method using a silica-based C8 column with 5 μm particle size, requiring a run time of 45 min (3). By using a gradient method and standard HPLC instrumentation, the analysis can be reduced to 7 min (4).

Anke Knõfel and Silvia Marten, KNAUER

Paracetamol is a major ingredient in numerous medications due to its analgesic and antipyretic properties. During its synthesis (Figure 1), a total of ten process-related impurities are observed. Several HPLC applications have been developed for the monitoring of these impurities (1, 2), including the European Pharmacopoeia which has adopted an isocratic HPLC method using a silica-based C8 column with 5 μm particle size, requiring a run time of 45 min (3). By using a gradient method and standard HPLC instrumentation, the analysis can be reduced to 7 min (4).

Figure 1

To remain competitive however, pharmaceutical laboratories require even faster methods with higher efficiency and rapid resolution. These priorities have led to the development of stable sub-2 μm columns which can meet these demands. Compared to 5 μm columns, sub-2 μm columns offer shorter analysis times, improvements in resolution, sensitivity, and peak capacity. This study describes a gradient method using a sub-2 μm column for the simultaneous determination of nine impurities and one degradation product.

Experimental

The analysis was performed on a KNAUER high pressure gradient PLATINblue UHPLC system, equipped with two P-1 Pumps, M-1 Degasser, AS-1 Autosampler, T-1 Column Temperature Manager, and UV-1 Detector.

Column: BlueOrchid 120 C18, 100 × 2 mm, 1.8 μm

Mobile Phase: A: ACN / B: Buffer (pH 3.7)

Results

Using a KNAUER PLATINblue UHPLC system and a BlueOrchid C18 1.8 μm column, paracetamol and ten impurities were separated in under 2 min (Figure 2), more than 3× faster than the conventional HPLC gradient method (4). Moreover, the UHPLC method required only one-fifth of the sample volume and eluent consumption was reduced to 18%.

Figure 2

The limit of detection (LOD) for all compounds was in the range of 0.01–0.08 μg/ml. Retention time reproducibility of the UHPLC method was in the range of 0.1– 0.7 % RSD (n = 5).

Conclusion

The high speed analysis of paracetamol in a pharmaceutical formulation illustrates how analytical labs can benefit from sub-2 μm columns like BlueOrchid in combination with a UHPLC system like PLATINblue, in terms of faster separations, higher resolution, higher sensitivity, and reduced mobile phase consumption.

References

(1) Rao R. Nageswara, A. Narasaraju, Analytical Science, 22: 287–292 (2006).

(2) B.S. Nageralli, J. Seetharamappa, B.G.Gowda, M.B. Melwanki, J. Chromatogr. B, 798, Number 1, 49–54 (2003).

(3) European Pharmacopoeia Monograph Paracetamol 01/2005:0049 / 2.2.29.

(4) KNAUER, Applications Journal, V7801, 07/2008, 79, at www.knauer.net.

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