Figure 2

A typical chromatogram of a standard mixture of 50 μg/ml FEX and its four related impurities; impurity A (A), impurity B (B), impurity C (C) and impurity D (D), each at a concentration of 25 μg/ml, a), a very high concentration of FEX (1000 μg/ml), b) of which the y-axis was rescaled to view the possible presence of impurities in bulk powder, b').