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Table 1 Optimization of the chromatographic conditions for determination of VPS by Method 1

From: Two novel UPLC methods utilizing two different analytical columns and different detection approaches for the simultaneous analysis of velpatasvir and sofosbuvir: application to their co-formulated tablet

Parameter

No. of theoretical plates (N)

Capacity factor (k′)

Tailing factor (Tf)

Column (A)

Column (B)

Column (A)

Column (B)

Column (A)

Column (B)

Column temperature °C

 Room temperature

2900.3

406.2

1.839

2.675

0.532

0.831

 30 °C

2941.6

1.987

0.660

 40 °C

4547.4

1009.7

2.183

2.038

0.536

0.900

 50 °C

5030.4

644.4

2.348

3.179

0.517

0.877

 60 °C

799.3

3.454

0.908

pH of mobile phase

 2.5

2900.3

406.2

1.839

2.675

0.532

0.831

 3.3

3921.4

408.2

2.744

4.150

0.528

0.947

 4.0

3305.7

410.6

3.976

6.425

0.491

0.924

Type of organic modifier of Conc 40% (v/v)

 Acetonitrile

2720.4

378.8

1.831

2.583

0.556

0.867

 Methanol

1140.1

365.4

1.843

2.621

0.514

0.907

 Ethanol

2304.3

352.9

1.870

2.592

0.413

0.871

Ratio organic modifier: mobile phase (acetonitrile) (v/v)

 40:60

3145.5

372.7

1.824

2.554

0.525

0.825

 60:40

2720.4

378.8

1.831

2.583

0.556

0.867

 80:20

2386.9

314.5

1.844

2.642

0.552

0.906

 90:10

2210.2

316.7

1.848

2.654

0.575

0.866

Effect of flow rate (mL/min)

 0.3

452.8

4.613

0.768

 0.5

 

205.0

 

1.433

 

0.750

 1.0

3551.6

 

2.376

 

0.571

 

 1.2

2900.3

1.839

0.532

  1. \( {\text{Number of theoretical plates }}\left( {\text{N}} \right)\, = \,5.54\left( {\frac{{{t}_{{R}} }}{{{Wh}/2}} } \right)^{2} \)
  2. \( {\text{Tailing factor }}\left( {\text{T}} \right)\, = \,\frac{{{W}_{0.5} }}{{2{f}}} {\text{k}^{\prime}} \, = \,{{({\text{tR}} {-}{\text{ t}}0)} \mathord{\left/ {\vphantom {{({\text{tR}} {-}{\text{ t}}0)} {{\text{t}}0}}} \right. \kern-0pt} {{\text{t}}0}} \),