Chemistry Reference
In-Depth Information
lipophilic compounds have a tendency to have particle size-dependent dissolution.
Particle size is often a CQA that must be optimized around the dissolution
performance of the SDD and maintained upon scale-up.
Physical Stability Risks
: SDDs are formulated with high-
T
g
polymers in either the
stable or metastable region. Selection of the drug loading and the polymer should
enable formulation robustness for process-relevant times and temperature expo-
sures, as well as in-process hold times before and during secondary drying (see
Figure 9.4).
Solubility in Common Solvents
: Selection of a common solvent for the drug,
polymer, and other excipients is critical to forming a homogeneous dispersion. It is
also important to identify a system that not only allows rapid drying, but also
reduces the potential for physical instability due to potential concentration gradients
as the droplet undergoes composition changes during drying (see Figure 9.5)
nition is a critical
component during formulation and process selection. The following considerations should
be accounted for to ensure both homogeneity of the SDD formulation and an ef
9.4.1.1 Spray Solution De
nition
Spray solution de
cient
process.
Figure 9.5.
Theoretical ternary phase diagram with example path from droplet-to-particle
composition.
