In
bi-polar parallel nozzle electroencapsulation, two oppositely charged droplet jets
are produced by electrospraying (electrostatic atomization), a method of extracting
micro- or nanodroplets from a body of liquid using electrical forces. The two
species of droplets are attracted to each other due to Coulombic forces. Upon
contact, droplets of similar size can merge into a single-phase, or form a core-shell
capsule structure, depending on the mutual miscibility of the liquids.

In
this work, an electroencapsulation setup was designed and experimented for the
single-step production of two types of drug carrier particles of 10–50 μm in
size: wrinkled, solid Eudragit L 100 enteric polymer micromatrix particles; and
spherical microcapsules consisting of a solid Eudragit E 100 polymer shell and
a liquid glycerol core. The carrier particle payload consisted of a model drug
(griseofulvin); or griseofulvin loaded, mesoporous silicon (PSi) nano- and microparticles,
which themselves are functional drug carriers. The goal was to obtain the
carrier particle payloads as either stable drug dispersions in a disordered
solid state, or non-agglomerated PSi nanoparticle dispersions, to enhance the
drug dissolution properties at release. The carrier formulations would
effectively render the payload in the form of an inert micropowder for purposes
of handling and dosing. In oral administration, the formulations were to shield
the payload from intestinal metabolism, and to restrain its release until
arrival to target pH-conditions.

The
carrier particles were characterized to evaluate these properties. The micromatrix
particles were proven stable and gastro-resistant in
vitro. Griseofulvin dissolution and
absorption properties improved significantly, the latter especially for the
drug loaded PSi payloads. Finally, the efficiency of the asymmetric core-shell
microcapsule production was optimized using Taguchi techniques. In conclusion,
electroencapsulation was found to be a potentially feasible method to improve
the oral bioavailability of poorly soluble drugs.

Furthermore,
partially crystalline piroxicam microparticles were produced by
electrospraying, and characterized. The crystalline phase was shown to consist
of a previously unknown, stable polymorphic form of piroxicam. The result
suggests the method could provide a unique way to produce novel drug polymorphs.
Thus, it is possible that the dissolution properties of certain drug materials
could be improved sufficiently to facilitate oral administration, without the
necessity to use more complex formulations.