drug discovery library design by biomimetic hplc

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Good drug efficiency

Solubility

Permeability

Good absorption

Low dose

Potency

SelectivityNon-toxic

Cellular potency

In vivo potencyefficacy

In vivo exposureGood PK/PD

structure

N

NN

NS

S

O


Drug discovery and development is a multi-parameter optimization process

DRUG


•After designing potent molecules project teams can apply various rules of thumb• Design a screening cascade and filtering process to find the best compounds for in vivo studies.

Potency

Ligand efficiency

Cellular potency

In vitro metabolism


Property CriterionPharmacologyPotency against target (Ki) <100 nMSelectivity against related off-targets

>100 x

Physicochemical propertieslogP <4Solubility >100 uMMW <450ADMECell permeability (Papp) <200 nm/sIntrinsic clearance <125 ul/min/mg proteinNo PGP <3SafetyCyp inhibition <1 uMhERG >10 uM


Filtering criteria should be flexible, with different weighing

The measurement errors should be considered in the cut off values and filtering

Improving one property may destroy another property

By sequential screening and decision making we may throw away good molecules


Potency/Selectivity

Physico-chemical and biomimetic properties

In vivo ADME/DMPK

properties


P. Barton, R. Riley, A new paradigm for navigating compound property related to drug attrition. Drug Discovery Today, 21 (2016) 72

LLEAT

AEI (2016)


BEI=-logKi/(MW/1000) LE = pIC50*1.37/nheavy LLE = pIC50 – clogP LLE(AT) = 0.111 + 1.36*LLE/nheavy BEI/LE ≈1000loge/13.3*0.594 ≈ 54.8 DEI= pIC50 +logDRUGeff logDRUGeffmax ≈ -logP DEI ≈ -LLE

Various efficiency parameters are in principle very similar

Ligand Efficiency Indices for Drug Discovery Towards an Atlas-Guided ParadigmAuthor(s):Celerino Abad-ZapateroISBN: 978-0-12-404635-1


LLE

DEI

Nearly all efficiency parameters relates to lipophilicity of the molecules

LLEAT

Find the optimum lipophilicity range


Reversed phase gradient retention time is proportional to the Chromatographic Hydrophobicity Index (CHI) (5 min method)

gradient tR at pH7.47.4 CHI at pH 7.4 Compound1.671 18.40 Theophylline1.768 23.60 Phenyltetrazole1.911 34.30 Benzimidazole2.132 42.00 Colchicine2.271 51.20 Phenyltheophylline2.475 65.10 Acetophenone2.642 71.50 Indole2.734 77.40 Propiophenone2.932 87.50 Butyrophenone3.113 96.20 Valerophenone


CHI TM1

Time0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80

AU

0.0

5.0e-2

1.0e-1

1.5e-1

2.0e-1

2.5e-1

3.0e-1

CHI TM1_LunapH74 Diode Array 254

Range: 3.969e-11.02

0.86

0.64

0.590.72

0.92

1.27

1.16

1.10

1.37

The CHI test mix is separated in less than 90 secNow we can determine compound’s lipophilicity in 90 sec using

various starting mobile phase pH

Courtesy of Shenaz Bunally

Chromatographic Hydrophobicity Index (CHI) – ChromlogD (90 sec method)

logP=-0.5 logP=5.5


PFI = ChromlogD + Number of aromatic rings

Calculate the number of aromatic rings

Convert CHI to ChromlogD

Convert it to Chromato-graphic Hydrophob-icity Index (CHI)

Measure reversed phase gradient retention time

Property Forecast Index, PFIChromlogD + Number of Aromatic rings


Property Forecast Index, PFICan be calculated in silico

In silico model developed by InSilicoLynx Ltd, by Mark Wenlock


PFI should be around 3 and 6

Young et al. Getting Physical in drug discovery II. – the impact of chromatographic hydrophobicity measurements and aromaticity, Drug Discovery Today, 16 (2011) 822 – 830.


MoA

pKi

Non SpecificBinding

DOSEDOSE

EFFECTEFFECT

F%AbsVdCLb

TBPBBPgpPerm.

MoApKi

BIO

PHA

SEA

DM

ETi

ssue

ratio

DOSEDOSE

EFFECTEFFECT

IN-VITROIN-VITRO IN-VIVOIN-VIVO

100% xDose

ConcseFreeBiophaEfficiency

[C]

[c]

EFF

ICIE

NC

Y

Drug efficiency definition – Dose and effect (PK/PD)

Braggio S, Montanari D, Rossi T, Ratti E. Drug efficiency: a new concept to guide lead optimization programs towards the selection of better clinical candidates. Expert Opinion on Drug Discovery. 2010;5:609–18.


Immobilised human serum albumin (HSA) Immobilised alpha-1-acid-glicoprotein (AGP) Immobilised artificial membrane (IAM)

These phases are commercially available!

Biomimetic stationary phase to measure protein and phospholipid binding


HSAkHSAK logexp

2 min

Similarly, we can derive phospholipid binding from gradient retention time measured on Immobilized Artificial Membrane stationary phase.

Retention times can be converted to % binding or partition coefficient K


VDss and Vdu

N

NN

NS

S

O

N

NN

NS

S

ON

NN

NS

S

O

N

NN

NS

S

O

N

NN

NS

S

O

N

NN

NS

S

O

N

NN

NS

S

O


HSA binding

IAM binding

Human clinical volume of distribution (Vdss) showed good correlation to the binding difference of compounds between phospholipids (IAM) and albumin (HSA)Drug efficiency showed good correlation with the sum of the two types of binding (IAM + HSA) which is the reciprocal value of the unbound volume of distribution Vdu

Schematic in vivo distribution of compounds between plasma and tissues

N

NN

NS

S

O

N

NN

NS

S

ON

NN

NS

S

O

N

NN

NS

S

O

N

NN

NS

S

O

N

NN

NS

S

O

N

NN

NS

S

O


What is the difference between IAM and HSA binding?


Nifedipine AmlodipineVd= 0.7 L/kg Vd= 21 L/kgt1/2= 6 h t1/2= 34 hHSA% = 88.8% HSA%= 91.4%CHI IAM = 30.4 CHI IAM= 51.0Predicted Vd= 0.7 L/kg Predicted Vd = 12.2 L/kgCalc logD=logP=3.58 calc logD= 1.50 calclogP=3.01No charge at pH 7.4 basic pKa = 9.45

The model from HSA and CHI IAM predicts the big differences in volume of distribution.

Examples for structural changes caused changes in volume of distribution


Human clinical logVdu can be modelled from the sum of the HSA and IAM binding

Valkó KL, NunhuckSB, Hill AP. Estimating unbound volume of distribution and tissue binding by in vitro HPLC-based human serum albumin and immobilised artificial membrane-binding measurements. Journal of pharmaceutical sciences 2011 ;100:849–62


Drugeff max is the reciprocal value of unbound volume of distribution (Vdu)

Vdu =Dose

Free plasma concentration

DEmax =Dose


DEmax =

Vdu


DEmax =

1

Vdu


100% absorption

No active transport or permeability

barrier

All non-specific binding

Maximum drug efficiency

logDEmax = 2-(0.23*logKHSA +0.43*logKIAM-0.72)

Drugeff max is the reciprocal value of unbound volume of distribution (Vdu)

Log Vdu


log(DRUGeff max HPLC)-1.5 -1 -0.5 0 0.5 1 1.5 2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

XY 0231.10423.0

81.02 R

Biomimetic DRUGEff Max

DR

UG

Eff M

ax

100Vu1Max% DRUGEff

In vivo and biomimetic DEmax show good correlation


Scatter Plot

logKHSA-0.5 0 0.5 1 1.5 2

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

HP

LC D

RU

GE

ff Max

Log k HSA

Size by: dose Colour by target class:

Scatter Plot

logkIAM0 0.5 1 1.5 2 2.5 3

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

Log k IAM7TM

Enzyme

Ion Channels

Nuclear Receptors

Undefined

Influence of HSA binding and IAM binding on HPLC derived DRUGEff max


Dose – a single parameter that combines potency and DMPK/ADME properties together

Dose *100[ free Bio phase conc]

DRUGeff

=


How early dose estimation correlates with real dose of 128 marketed drugs?

Valko K, Chiarparin E, Nunhuck S, Montanari D. In vitro measurement of drug efficiency index to aid early lead optimization. Journal of pharmaceutical sciences 2012, 101:4155–69.


In vitro DEmax improves the dose prediction

Incorporating DEmax improves the dose prediction


Bio-Mimetic Chromatography Consultancy offers:


Recent Publications (BMCC)


Thank you for your attention

Contact InformationName: Klara ValkoPhone: +44 7521 989 558Email: Klara_Valko@bio-mimetic-

chromatography.com

drug discovery library design by biomimetic hplc

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