Ingredient-specific particle sizing
This article describes a technique using a combination of Raman chemical imaging and optical microscopy that allows product developers to obtain particle size distributions of both API and excipient in a suspension.
Nasal and MDI suspensions that contain insoluble
excipients in addition to the API present a special
challenge for product developers who need to
determine the particle size distribution of the API.
While the pharmaceutical industry has had a number
of well-established methods for determining
the particle size distribution (PSD) of a drug in
orally inhaled and nasal drug products (OINDPs),
particularly cascade impaction, those methods cannot
differentiate between ingredients. If the PSDs
of the API and an excipient overlap, accurately
determining the PSD of the API becomes impossible
with standard instruments.