Background
Methods
Chemicals
Solutions
Apparatus and operating conditions
Operations | |
---|---|
1. Capillary rinse | 1 M HCl; 2 min; 20 psi |
2. Capillary rinse | 1 M NaOH; 1 min; 20 psi |
3. Capillary rinse | Electrolyte solution; 1 min; 20 psi |
4. Sample introduction (anodic side) | Analyte; 3 secondes; 0.3 psi (3.5 nL) |
5. Wait | Water; 0 seconde |
6. Separation | 6 min; 10 kV (500 V.cm-1); 0.17 min ramp voltage; 25°C (i = 50 μA) |
7. Detection | UV; 214 nm; spectral bandwith 10 nm; acquisition rate 4 Hz; filter normal |
8. Autozero | 1 min |
Results and discussion
Preliminary studies in capillary zone electrophoresis
Investigations in micellar electrokinetic capillary chromatography
Optimization of the surfactant concentration
Selection of a sample solvent
Optimization of the injected volume and sample concentration
Selection of an internal standard
Selection of detection wavelength
Capillary rinse between injections
Evaluation of method performances
Selectivity
Excipients | Coarsucam® | ASAQ Denk® |
---|---|---|
Sodium croscarmellose | x | x |
Povidone K30 | x | |
Magnesium stearate | x | x |
Colloidal anhydrous silica | x | x |
Calcium carbonate | x | |
Maize starch | x | |
Microcrystalline cellulose | x | x |
Talc | x | |
Calcium hydrogen phosphate dihydrate | x | |
Lactose monohydrate | x |
Linearity of the response function
System precision
Accuracy: Recovery studies
Exp. No. | Theoretical content (%) | Added amount (mg) | Found amount (%) | Recovery (%) | Mean recovery ± s (%) |
---|---|---|---|---|---|
AS | |||||
1 | 15.84 | 16.23 | 102 | ||
2 | 80 | 15.99 | 16.12 | 101 | 101 ± 0.8 |
3 | 16.16 | 16.35 | 101 | ||
1 | 19.85 | 20.21 | 102 | ||
2 | 100 | 19.97 | 20.61 | 103 | 102 ± 0.7 |
3 | 20.06 | 20.48 | 102 | ||
1 | 23.57 | 23.46 | 100 | ||
2 | 120 | 24.00 | 24.54 | 102 | 101 ± 1.4 |
3 | 24.17 | 24.44 | 101 | ||
AQH | |||||
1 | 55.26 | 54.74 | 99 | ||
2 | 80 | 55.65 | 55.03 | 99 | 99 ± 0.3 |
3 | 56.81 | 56.47 | 99 | ||
1 | 69.3 | 68.49 | 99 | ||
2 | 100 | 70.31 | 69.16 | 98 | 98 ± 0.9 |
3 | 70.87 | 68.84 | 97 | ||
1 | 83.2 | 82.69 | 99 | ||
2 | 120 | 85.05 | 83.06 | 98 | 99 ± 1.1 |
3 | 93.92 | 93.47 | 100 |
Limit of quantification (LOQ)
Application to commercial tablet formulations
Tablets | % of the labelled claim | |
---|---|---|
AS | AQH | |
Coarsucam®; 25 mg AS – 88.16 mg AQH (67.5 mg AQ base) | 101.6 | 99.6 |
Coarsucam®; 50 mg AS – 176.32 mg AQH (135 mg AQ base) | 98.1 | 100.2 |
Coarsucam®; 100 mg AS – 352.64 mg AQH (270 mg AQ base) | 97.0 | 98.1 |
ASAQ Denk®; 100 mg AS – 352.64 mg AQH (270 mg AQ base) | 98.0 | 99.5 |