Powder Distribution and Weighing System for Library Compounds
Compound libraries are the potential gold mines
of pharmaceutical and chemical companies.
Liquid handling for the dissolution of the library compounds has been automated for many years.
The most tedious procedure, though, the distribution
and weighing of the original solid dry-stored
library compound, is still done manually. The
CALLI-L fills this gap. It is specifically designed for
the distribution of dry, powder library samples for
dissolution, distributing the samples directly from
their original library vial without any additional
CALLI-L is based on the well-proven Zinsser liquid handling
platform with integrated powder and liquid handling, a weighing cell, mixing devices, a capper/
decapper and a visual camera. The customer library
vials are placed in racks on the platform.
CALLI-L is an automatic workbench system,
1.5 or 2m long, customized to the
individual requirements for medium or
high throughput. It is based on a X,Y,Z
pipetting station with an integrated
robotic arm which can be equipped with
all the functions needed for dissolution
of the compounds:
Accurate weighing of compounds
Powder Dispensing from 1mg to 50mg
Precise liquid handling
Capper/Decapper for screw neck vials
Efficient mixing and stirring
Visual Control of the dissolution status
The combination of clever hardware and software
make CALLI-L the ideal workhorse for sample
preparation of library samples. By automating
the entire workflow and using the original sample
containers, it frees laboratory staff from the
tedious, time-consuming and repetitive work so
that they can concentrate on more intelligent
For sample identification the library
compounds are placed in barcode labeled
vials on the platform.
CALLI-L reads from the barcode
which compound it is handling, how
many dissolution vials shall be prepared,
which target concentration
should be reached. Each sample is
tracked throughout the run.
The distribution process is controlled
by a built-in weighing cell to monitor
the mass distribution of powders
in the range from less than 1mg to
50mg. CALLI-L detects the level of
the solid material in the library vial.
Even a small layer on the bottom
can be transferred to the dissolution
vial or plate.
Addition of solvent
Based on the actual weight and the
given target concentration the solvent
is added. Up to 6 different solvents
can be handled in one run,
using the integrated 6-way valve.
An integrated camera checks the
dissolution status of the compound
and based on its result it can trigger
different actions: Mixing by vortexing,
sonication, addition of a different
solvent or in the end it can
discard the sample from the rest of
the run. The camera can check the
dissolution status of the samples at
any given time.
For efficient mixing vortexers, magnetic
stirrers or overhead stirring
are available which are integrated
into the platform.
All mixing devices can be equipped
with software-controlled temperature
The samples can be sonicated by either
using a sonication probe or by
placing the sample containers into a
sonication bath. The sonication step
can either be implemented as a
standard routine in the method for
all samples or it can be used as an
extra treatment where necessary.
For hygroscopic compounds and
when handling DMSO to minimize
the risk of compound precipitation
the entire dissolution step can be
performed under argon. With its enhanced
technology it is not necessary
to flood the entire system with argon
thus keeping the cost and weight of
the instrument to a minimum.
The WinCALLI software controls the
weighing, dissolution and sample
distribution. It keeps track of the
samples and exchanges data with
all commercial mass storage databases
such as ORACLE®. With the
scheduler, it controls and optimizes the methods, enabling
the system to work with both arms completely independently.
A complete sample audit trail is provided,
which is used to control the system and for the documentation
of each run.
Capping & Decapping
A capper/decapper unit can open and
close screw capped sample vials to
minimize their exposure to air. It can
also close the reactors to prevent
High Reproducibility & Precision
Weight reproducibility depends upon
the particle size distribution within
the sample. Powders with narrow
particle size show precise distribution
with excellent reproducibilities. Test results with different
powders have given reproducibilities of ±5% for 1mg,±3% for 10mg, ±1% for 50mg, and 1% for 150mg.