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Table 6 Binding to plasma and media proteins

From: An in vitro toolbox to accelerate anti-malarial drug discovery and development

Compound

Fraction unbound ± SD

Human Plasmaa

Albumaxa

10% FCS in DMEMa

HLMa

Ionized or partially ionized bases at physiological pH

 Cycloguanil

0.75 ± 0.040

0.88 ± 0.057

0.94 ± 0.064

0.72 ± 0.083

 Doxycyclin

0.23 ± 0.090b

0.41 ± 0.023

0.44 ± 0.070

0.93 ± 0.045

 Pyronaridine

0.090 ± 0.012b

0.69 ± 0.023

Not assessed

0.29 ± 0.018

 Proguanil

0.34 ± 0.010

0.80 ± 0.021

Not assessed

0.33 ± 0.014

 Primaquine

0.26 ± 0.023

0.96 ± 0.056

0.78 ± 0.025

0.56 ± 0.050

 Chloroquine

0.54 ± 0.048

0.97 ± 0.069

Not assessed

0.50 ± 0.032

 Chlorproguanil

0.10 ± 0.0070

0.50 ± 0.020

Not assessed

0.052 ± 0.004

 Azithromycin

0.34, 0.35b

0.76 ± 0.065

Not assessed

0.70 ± 0.060

 AQ-13

0.43 ± 0.022

0.85 ± 0.028

Not assessed

0.66 ± 0.048

 Desethylamodiaquine

0.17 ± 0.0020

0.75 ± 0.074

Not assessed

not assessed

 Quinine

0.37 ± 0.040b

0.69 ± 0.090

Not assessed

0.57 ± 0.036

 Clindamycin

0.19 ± 0.011

0.65 ± 0.066

Not assessed

0.67 ± 0.084

 KAF156

0.069 ± 0.013b

0.38 ± 0.017

0.477 ± 0.032

0.14 ± 0.0060

 M5717

0.24 ± 0.0020b

0.55 ± 0.041

0.638 ± 0.065

0.50 ± 0.041

 OZ277

0.086 ± 0.0080

0.29 ± 0.021

Not assessed

0.044 ± 0.0050

 Mefloquine

0.015 ± 0.0010b

0.27 ± 0.019

Not assessed

0.050 ± 0.0060

 Amodiaquine

0.089 ± 0.0080

0.67 ± 0.033

Not assessed

0.91 ± 0.094

 NPC1161B

0.00074 ± 0.00016c

0.035 ± 0.0020

0.043 ± 0.004

CNDe

 Ferroquine

0.041 ± 0.0010c

0.52 ± 0.031

0.364 ± 0.026

0.27 ± 0.032

 Naphthoquine

0.018 ± 0.0010c

0.27 ± 0.035

Not assessed

0.21 ± 0.015

 Tafenoquine

0.00070 ± 0.00017c

CNDe

0.038 ± 0.001

0.0020 ± 0.00030

 MMV253

0.017 ± 0.00020c

0.48 ± 0.026

Not assessed

0.11 ± 0.017

 MMV052

0.00040 ± 0.00010c

0.014 ± 0.0010

Not assessed

0.0010 ± 0.00010

 Piperaquine

0.0003 ± 0.0001c

0.019 ± 0.0040

0.092 ± 0.0030

0.013 ± 0.0020

 Halofantrine

< 0.0001c

0.0080 ± 0.0010

Not assessed

0.0020 ± 0.00020

 TDD-E209

< 0.0001c

0.0070 ± 0.0010

Not assessed

0.00030 ± 0.000010

 Lumefantrine

< 0.0001c

CNDe

Not assessed

CNDe

Ionized acids at physiological pH

 Sulfadoxine

0.036 ± 0.0010

0.50 ± 0.030

0.86 ± 0.044

0.93 ± 0.086

 Sulfamethoxazole

0.32 ± 0.024

0.67 ± 0.120

0.87 ± 0.058

1.00 ± 0.033

 Artesunate

0.27 ± 0.0080d

0.14 ± 0.0070d

0.72 ± 0.026

CNDd

 Atovaquone

< 0.0001c

CNDe

CNDe

~ 0.0020

Zwitterionic or partially zwitterionic at physiological pH

 P218

0.13 ± 0.013

0.41 ± 0.022

0.684 ± 0.017

0.88 ± 0.041

 JPC3210

0.0028 ± 0.00020c

0.21 ± 0.012

0.227 ± 0.012

0.029 ± 0.0030

Neutral at physiological pH

 Dapsone

0.27 ± 0.019

0.63 ± 0.11

Not assessed

0.86 ± 0.059

 Dihydroartemisinin

0.21 ± 0.010d

0.34 ± 0.018d

Not assessed

0.87 ± 0.10d

 DSM421

0.039 ± 0.007

0.43 ± 0.020

0.615 ± 0.043

0.77 ± 0.065f

 Pyrimethamine

0.095 ± 0.0010b

0.46 ± 0.090

0.48 ± 0.034

0.54 ± 0.097

 MMV048

0.11 ± 0.0070b

0.46 ± 0.022

0.653 ± 0.060

0.61 ± 0.014

 Artemisone

0.12 ± 0.0060

0.46 ± 0.013

Not assessed

0.44 ± 0.024

 Artemether

0.038 ± 0.0090c

0.46 ± 0.039

Not assessed

0.50 ± 0.052

 SJ733

0.085 ± 0.012c

0.40 ± 0.040

Not assessed

0.58 ± 0.069

 DSM265

0.0018 ± 0.00010c

0.18 ± 0.0050f

0.366 ± 0.041

0.28 ± 0.0070f

 KAE609

0.0016 ± 0.00010c

0.044 ± 0.0040

Not assessed

0.019 ± 0.0010

 OZ439

< 0.0001c

0.010 ± 0.0010

Not assessed

0.0010 ± 0.00010

 ELQ300

0.00010 ± 0.000010c

CNDe

0.001 ± 0.001

0.002 ± 0.00010

  1. CND could not determine
  2. aMean ± SD, n = 3–4 replicates; ultracentrifugation used unless indicated otherwise
  3. bRED device with diluted plasma correcting for the dilution factor with 6 h dialysis
  4. cRED device with diluted plasma correcting for the dilution factor; presaturation of device and 24 h dialysis
  5. dInstability evident; where values are given they represent an estimate only
  6. eCompound not detected in free fraction
  7. fData for DSM265 from [79] and for DSM421 from [78]