Formulation Scientist, Recipharm
Many newly discovered compounds are limited by is- sues associated with poor water solubility, meaning that drugs do not adequately dissolve in physiological
fluids. Poor solubility can lead to low bioavailability resulting
in suboptimal drug delivery, and despite possessing superior
pharmacological properties, these drug molecules risk withdrawal from development.
Solubility is critical in achieving the required concentration of
a compound for the desired pharmacological response. In the initial stages of drug design and development, simple liquid formulations are used to evaluate a compound’s pharmacology, phar-macokinetics and toxicology. During this process, compounds
that suffer from low aqueous solubility need to be paired with
excipients that can adequately solubilize them.1,2 Until recently,
the identification of an appropriate excipient has relied on a trial-and-error-based methodology. The time-consuming and expensive nature of this process has paved the way for the development
of a new high-throughput screen (HTS) method that can optimize the selection of appropriate solubilization excipients.
DRUG SOLUBILITY ENHANCEMENT TECHNIQUES
Solubility issues complicate the formulation and development of
new chemical entities (NCEs), but there is an array of techniques
available to enhance the solubility and improve the bioavailability
of these drugs. The strategies include either solid form manipulation using amorphous, salt or cocrystal form, or solvation methods
using materials that can solubilize the drug compound such as cosolvents, surfactants or cyclodextrins.
3, 4 Selection of the solubility
method will depend on several factors, including a compound’s
unique properties, the physical state of the formulation, the site of
adsorption and the required dosage form characteristics. Generally,
solvent modifications and carrier systems are the most widely used
approaches in developing liquid formulations due to their ability
to only impact the solvation characteristics of a compound rather
than its solid-state properties and ease of preparation.
EXPLORING A MORE EFFICIENT APPROACH
While there are many solubilization techniques available to formulation scientists, the trial-and-error-based approach of selecting the
Optimizing Drug Solubility
Selecting excipients for drug solubilization with a new high-throughput screen method