The Application of Non-Combinatorial Chemistry to Lead Discovery - Presentation Transcript
The Application of Non-Combinatorial Chemistry to Lead Discovery Dr Graham F. Smith Library Design and Production Group Pfizer Global R & D Sandwich, UK See Drug Discovery Today, 2001, volume 6, No. 15, p779-785
Parallel synthesis is a powerful technique The application of automation, parallelisation and miniaturization of Organic Chemistry has radically changed Chemistry Departments in Pharmaceutical companies. Combinatorial Chemistry is only one possible use of parallel synthesis
Our Groups Initial Goals
To create a technology group which could make large numbers of HPLC pure single compounds
To create systems and processes which allow single compounds from an array to be selected and made in parallel
To combine the above with compound design at the individual compound level
These are then combined to make a library
To perform all of the above in a high throughput environment for file enrichment and later “lead optimisation”
Non Combinatorial Chemistry
Parallel synthesis of single compounds
Not all combinations of monomers
No artificial constraints on array shape or dimensions (e.g 2000 from 200 X 150 x 30)
Allows “cherry picking” of desired products from an array based on:
diversity
similarity
calculated property e.g. Rule of 5
predicted activity
gut feeling, crazy hunch, any of the above in combination…..
Allows maximum diversity or similarity from a given number of compounds
Uses all the locally available monomers
Diversity
File enrichment for hit seeking requires maximal diversity in drug space and limited redundancy
populate with low diversity and small cluster sizes
Hit follow up requires more similarity and redundancy
populate with high diversity and large cluster sizes
Need metrics which map chemical similarity to biological similarity
Large clusters high similarity Cluster algorithm from Mike Miller - PGRD Groton USA Small clusters low similarity Spotfire Shenghua Shi
IT for Non Combinatorial Chemistry - LiCRA
Li brary C reation R egistration and A nalysis
Oracle database, batch based not array (plate) based
MACCS database for structures
VB interface
Migration to Java and xml Q1 2002
Zhenwei Peng
Inputs simple and general
SDF file with batch numbers
comma separated file with batch numbers & starting materials
e.g. Batch#1,benzylamine#1,benzoic acid#1
synthesis plate format & monomer racks are created on the fly by analysis of library product composition
Output = complete registration file to corporate DB
structure, batch#, product weight, chemist, precursors etc.
Stores, analyses and reports history of synthesis and QC data
LDP - Technology
96 well 1ml Teflon plates
Robbins FlexChem solid phase filter plates
Tecan Genesis 8 needle x 6
dispensing
LLE
SPE
resin washing
Hamilton SPE x 2
Bohdan tube weighing ( for products) x 3
Genevac (HT12 & series 2) x 6
Gilson 215 based HPLC x 16
UV fraction detection
9ml 48 Well plate bar coded collection plates
Technology in use (2)
MicroMass Platform MS or TOF x 6
4 way Mux recently added for pre QC
ELSD (Polymer labs & Aztec)
Beckman ORCA 2M track robot based fraction selector (Anachem ~$1MM)
Molecular ion detection
ELSD quantification
standard at beginning and end of every plate
multi detector rule based purity decision
on the fly product plate reformatting (red, amber, green)
on line progress monitoring from remote PC
~60,000 crude fraction samples in 2002
24 x 7 operation with maintenance (1 FTE)
Unforeseen advantages of Non Combinatorial Chemistry and HPLC library purification
HPLC purification of plates ordered by clogP gives easier purification method development
Large monomers sets define bigger and better protocols after several iterations
Can take inputs from combinatorial and non combinatorial designs together
Leads are easily followed by discovery chemistry
Much larger monomer set = diversity
weighing more monomers manually intensive
inventory of more monomers needs resources (IT, $$ and FTE)
Less reliance on the activity or chemical success of single monomers in a library
Summary
Non combinatorial chemistry is easily achieved within our LiCRA IT system
High Throughput semi prep reverse phase HPLC is capable of >50,000 product samples per annum delivering ~6mg per sample
Optimisation of library derived leads is more efficient with non combinatorial chemistry
File enrichment is more efficiently achieved with non combinatorial chemistry
Sparse matrix, cherry picked libraries produce HTS actives
“ hit rate” greater than the average screening file
no false positives due to “artefacts” or mixtures
these actives have opportunity of efficient // synthesis follow up from a large chemically validated VL
The Application of Non-Combinatorial Chemistry to more
The Application of Non-Combinatorial Chemistry to Lead Discovery. The evolution of purified non-combinatorial libraries as the way forward in parallel synthesis. Given at Lab automation 2002 Palm Springs less
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