Chemistry Reference
In-Depth Information
3
AMORPHOUS SOLID
DISPERSION SCREENING
Ann Newman
Seventh Street Development Group, Lafayette, IN, USA
3.1 INTRODUCTION
Finding the optimal form for drug development can involve a number of different
screening activities, including a search for polymorphs, salts, cocrystals, and/or amor-
phous solid dispersions. Solid form screening activities can be performed in early or late
development with different strategies at each stage of development (Figure 3.1).
Amorphous solid dispersions are often included as part of this screening strategy,
but they can also be part of a formulation strategy, especially for preclinical studies,
based on solubility risk assessment [1]. High-risk compounds will require special
formulations that include amorphous solid dispersions. Whether the focus is on API
or formulation, an amorphous solid dispersion may be necessary to
find an optimal form
for further development.
An amorphous dispersion screen is performed to
find a suitable amorphous dispersion
that exhibits acceptable properties. The screening performed in early development may
focus on parameters such as solubility, supersaturation, short-term physical and chemical
stability, and animal bioavailability to get into early-phase clinical trials quickly and
establish proof of concept. Characterization is usually limited to essential information,
such as amorphous structure, glass transition temperature (
T
g
), water/solvent content, and
