Inhalation powders for nasal and pulmonary delivery
These studies are mainly addressed to dry powder inhalers (DPI). Therefore, the focus is on
the techniques for powder transformation in order to obtain particles of active substances
characterized by favorable metering, aerosolization and
lung deposition.
The unique features of the lung, namely its large
surface area, high permeability and wide blood supply,
make pulmonary route an attractive non-invasive way for
the systemic administration of peptides and proteins. The
possibility to administrate the micronized powder of
insulin ( a polipeptidic hormone) by DPI systemhas been
studied.
Pulmonary Particles
The technique of particle agglomeration is also
studied with the aim to have flowable powders composed of microparticles. These agglomerates are
defined chimeral or troian due to their dimension that, being large for agglomeration, is in reality
small, since the agglomerares are easy broken apart by water contact. These powders are suitable
for nasal, buccal or dermal administration. This concept of chimeral nasal powder was applied to an
analgesic model drug (morphine). The nasal administration of this analgesic aims to substitute the
low-accepted injection route.
Therefore, nasal powder of analgesic drug mixed with inert spray-dried particles were
agglomerated in chimeral pellets. Their larger particle size (about 300 µm) made easier the dosage.
The large agglomerates are fragmented by insufflation to obtain the deposition on the nasal mucosa.
The insufflation delivery properties of chimeral agglomerates were studied in order to
determine, quantitatively (amount of dose emitted) and qualitatively (images of delivery sequence),
the dose delivery performance.
before insufflation
during insufflation
Deposition into a human nasal cast of the chimeral agglomerates
after