Physico-Chemical
Contract Research | Absorption/Transport
| Metabolism | Induction
| Physico-Chemical | Toxicity
| Sponsor-Initiated Protocols
 Solubility
Effective delivery of drugs to the biological site of action (e.g. oral
or intravenous bioavailability) is influenced by the solubility of the
drug. For example, a drug must be soluble to allow intestinal absorption
to occur or for preparation of a formulation suitable for IV injection.
In addition, information regarding solubility can be used to qualify biochemical
assays. We would determine the solubility of your compounds by one of
two methods. In the first option, we would determine aqueous solubility
by traditional "shake-flask" method. Aqueous solubility is determined
by HPLC and UV-absorbance analysis of DMSO stock solutions and samples
equilibrated in buffer. In the second option, we would determine solubility
in high throughput mode using the BD Gentest™ Solubility Scanner. For
more information about the principles of operation, refer to the Solubility,
Formulation and Distribution chapter of this catalog. Unlike plate nephelometry,
the Solubility Scanner uses BD's flow cytometry technology to accurately
detect and characterize individual particles. As a result, the system
can reproducibly detect solubilities below 1 µM.
Log P
Log P is a physico-chemical parameter of aqueous and lipid solubility
that influences the delivery of drugs to their target. After equilibration
in water (or buffer) and octanol, phases are diluted in water/methanol
and analyzed by LC/MS.
Plasma Protein Binding
Drug-plasma protein binding is one of the many factors which influence
bioavailability of a drug. Efficacy, distribution and elimination of a
drug can be affected by the reversible binding of the drug to plasma proteins,
such as albumin and acid glycoprotein. BD Gentestsm Contract
Research Services now offers the following GLP Plasma Protein Binding
(PPB) services, to determine the % drug bound to plasma proteins and associated
with blood cells: PPB by ultrafiltration, PPB by equilibrium dialysis,
and Blood Cell Partitioning, with human, rat, mouse, monkey, dog and rabbit
plasma and blood.
Protein Binding [ PDF
]
Consult the ADME experts at 888.334.5229 or via email
to discuss your needs.
The complete FDA guidance document can be viewed on the web at:
http://www.fda.gov/cder/guidance/clin3.pdf
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