Safinamide Impurity Profiling by HPLC Assay Methods
Neil J. Williams1, Jenna Milliken1
MilliporeSigma
INTRODUCTION
A simple and accurate method was developed for purity analysis of safinamide using high-performance liquid chromatography with a diode array detector (HPLC-DAD). The method was developed for a family of safinamide compounds consisting of the active pharmaceutical ingredient safinamide and multiple corresponding impurities. This is to our knowledge the first reported method for safinamide and related impurities. Safinamide free acid, safinamide mesylate, safinamide defluor-derivative, and safinamide imidazolidinone can be resolved in a 20-minute method using an Ascentis® Express C8 column (150 x 4.6 mm, 5 μm). A gradient that utilized 0.1% trifluoroacetic acid in water and acetonitrile was employed. Under the applied conditions the system suitability criteria are met. The method demonstrates good resolution and selectivity, reproducibility, and sensitivity.

Safinamide Free Acid
PHR2380
Safinamide Mesylate
PHR2379
Safinamide Deflour-Derivative
PHR2381
Safinamide Imidazolidinone
PHR2382
Column: | Ascentis® Express C8, 150 x 4.6 mm I.D., 5µm (50392-U) |
Mobile phase: | [A] Water with 0.1 % trifluoroacetic acid; |
Gradient: | Time (min) %A %B 0-5 90 10 5-8 90-80 10-20 8-10 80-70 20-30 10-15 70-60 30-40 15-17 60-85 40-15 17-18 85-90 15-10 18-20 90 10 |
Flow rate: | 1.50 mL/min |
Pressure: | 184-197 bar (2669-2858 psi) |
Temperatures: | Column: 45°C |
Detection: | UV @ 226 nm (analytical flow cell; 10 µL) |
Injection: | 10 µL |
Samples |
|
---|---|
Diluent: | Methanol |
System suitability solution: | 10.0 mg of safinamide mesylate in 25 mL diluent (0.400 mg/mL) |
Resolution solution: | 12.0 mg of each respective compound (safinamide mesylate, safinamide free acid, safinamide defluor-derivate and safinamide imidazolidinone) individually in 25 mL diluent. Then 0.25 mL of each solution were combined in a 1.5 mL vial via syringe (0.120 mg/mL) |

Figure 1.Blank chromatogram.

Figure 2.Chromatogram for safinamide mesylate system suitability solution.

Figure 3.Chromatogram for resolution solution.
Peaks | Compound | Retention Time (min) | RRT | Resolution | Theoretical plates | Tailing factor |
---|---|---|---|---|---|---|
1 | Safinamide imidazolidinone | 10.7 | 0.94 | - | 87122 | 0.93 |
2 | Safinamide defluor-derivative | 11.0 | 0.97 | 2.1 | 100843 | 0.93 |
3 | Safinamide mesylate | 11.4 | 1.00 | 2.9 | 114974 | 0.96 |
4 | Safinamide free acid | 11.7 | 1.03 | 2.7 | 93783 | 1.06 |

Figure 4.Calibration curve of safinamide mesylate.

Figure 5.Calibration curve of safinamide free acid.

Figure 6.Calibration curve of safinamide defluro-derivative.

Figure 7.Calibration curve of safinamide imidazolidinone.
CONCLUSION
A new method was developed for analyzing the purity of safinamide and its related compounds using high-performance liquid chromatography with a diode array detector. The method uses an Ascentis® Express C8 HPLC column and a gradient of 0.1% trifluoroacetic acid in water and acetonitrile and takes 20 minutes to resolve the compounds. The method is reproducible and sensitive and shows good resolution and selectivity.
See also Small Molecules Analysis & Quality Control (QC) for more information on other applications or use our chromatogram search.
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