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Table 3 Control strategy for stability methods of AV obtained by CCD design

From: Comprehensive stability-indicating method development of Avanafil Phosphodiesterase type 5 inhibitor using advanced Quality-by-Design approach

Factors

Attribute or parameter

Range studied

Optimized data

Proposed range

Purpose of control

Mobile phase ratio (Buffer:ACN)

Resolution

40:60, 50:50, 60:40, 70:30, 80:20 v/v

60:40, v/v

60:40 ± 2, v/v

Better separation between peaks, to get > 2 resolution

pH of buffer

Resolution

2.5, 3.5, 4.5, 5.5, 6.5

4.5

4.5 ± 0.2

Better separation between peaks, to get > 2 resolution

Flow rate of mobile phase

Resolution

0.75, 0.5, 1, 1.25 mL/min,

0.9 mL/min

0.9 ± 0.2 mL/min

Better separation between peaks, to get > 2 resolution

Temperature of column oven

Resolution

0 °C (no control),

10, 20, 30, 40 °C,

20 °C

20 ± 2 °C

Effective parameter for changing band spacing and improving resolution

Organic phase type

Resolution

ACN,

MeOH

ACN

ACN

To improve peak shape and resolution

Degase time

Resolution

10–25 min

12–15 min

(12–15 min) ±  2

To remove air bubble from mobile phase

Sample volume

Resolution

5–20 μL

10 μL

10 μL ± 0.1

To reduce chances of more sample loading

Column type

Resolution

C18, C8

C18

C18

For better separation and resolution

Buffer type

Resolution

Ammonium formate,

ammonium acetate

Ammonium acetate

Ammonium acetate

Ammonium salts are used for LC–MS compatible method

Buffer strength

Resolution

5–10 mM

10 mM

10 mM

Buffer used to maintain consistent retention, reproducibility, and selectivity

Detection wavelength

Resolution

230–250 nm

239 nm

239 nm

More absorbance at wavelength maxima