1 research outputs found
Microstructural Distinction of Electrospun Nanofibrous Drug Delivery Systems Formulated with Different Excipients
The
electrospun nanofiber-based orally dissolving webs are promising candidates
for rapid drug release, which is due to the high surface area to volume
ratio of the fibers and the high amorphization efficacy of the fiber
formation process. Although the latter is responsible for the physical
and/or chemical instability of these systems. The primary aim of the
present study was to elucidate how the addition of polysorbate 80
(PS80) and hydroxypropyl-Ī²-cyclodextrin (HP-Ī²-CD) influenced
the electrospinning process, the properties, and the behavior of the
obtained nanofibers. In order to reveal any subtle changes attributable
to the applied excipients, the prepared samples were subjected to
several state of the art imaging and solid state characterization
techniques at both macroscopic and microscopic levels. Atomic force
microscopy (AFM) revealed the viscoelastic nature of the fibrous samples.
At relatively low forces mostly elastic deformation was observed,
while at higher loads plasticity predominated. The use of polysorbate
led to about two times stiffer, less plastic fibers than the addition
of cyclodextrin. The <sup>1</sup>Hā<sup>13</sup>C nuclear magnetic
resonance (NMR) cross-polarization build-up curves pointed out that
cyclodextrin acts as an inner, while polysorbate acts as an outer
plasticizer and, due to its āliquid-likeā behavior,
can migrate in the polymer-matrix, which results in the less plastic
behavior of this formulation. Positron annihilation lifetime spectroscopy
(PALS) measurements also confirmed the enhanced mobility of the polysorbate
and the molecular packing enhancer properties of the cyclodextrin.
Solid-state methods suggested amorphous precipitation of the active
ingredient in the course of the electrospinning process; furthermore,
the nature of the amorphous systems was verified by NMR spectroscopy,
which revealed that the use of the examined additives enabled the
development of a molecularly dispersed systems of different homogeneities.
An accelerated stability study was carried out to track physical state
related changes of the incorporated drug and the polymeric carrier.
Recrystallization of the active ingredient could not be observed,
which indicated a large stress tolerance capacity, but time-dependent
microstructural changes were seen in the presence of polysorbate.
Raman mapping verified homogeneous drug distribution in the nanofibrous
orally dissolving webs. The performed dissolution study indicated
that the drug dissolution from the fibers was rapid and complete,
but the formed stronger interaction in the case of the PVA-CD-MH system
resulted in a little bit slower drug release, compared to the PS80
containing formulation. The results obviously show that the complex
physicochemical characterization of the polymer-based fibrous delivery
systems is of great impact since it enables the better understanding
of material properties including the supramolecular interactions of
multicomponent systems and consequently the rational design of drug-loaded
nanocarriers of required stability