Characterization of functionalized calcium carbonate as a new pharmaceutical excipient

Excipients are indispensable functional components, which are used to develop innovative, robust,
and reproducible formulations with good patient compliance due to optimized plasma concentrations
and less side effects. Nowadays, new excipients have to show a multifunctionality in order to
be used for unique applications that are not feasible with existing excipients. This multifunctionality
can be achieved by co-processing excipients, where undesirable properties of an excipient are
masked, favorable attributes are retained, and new properties supplement the substance.
The main aim of this thesis was to map the applicability of such a co-processed novel excipient,
FCC, in the field of pharmaceutical technology.
The results of the mechanistic study showed that the attributes of FCC present a striking success
in the field of excipient research. FCC-based tablet formulations had mechanical properties equal
or superior to those of conventionally used excipients such as microcrystalline cellulose (MCC),
mannitol, or calcium carbonate. FCC tablets with high tensile strength and high porosity were
obtained already at low compressive pressures. The key factor for the outstanding performance
of FCC was the lamellar structure of the particle, which formed a porous meshwork (intraparticle
porosity), resulting in a high specific surface area available for particle bonding.
The limitations of poor flowability and high bulk density of FCC powder during direct compression
were overcome by granulation. FCC granules prepared by roller compaction showed excellent
flowability and reduced bulk volume, whereas all the outstanding properties of the powder, such as
compactability and compressibility, were preserved. The dry granulation process converted FCC
into a suitable form for scale-up processes on high-throughput tablet presses. Roller compaction is
the process of choice if porosity and high surface area of FCC particles have to be preserved during
granulation process.
On the examplary model of direct compressed ODTs, the applicability of FCC was investigated.
ODTs containing FCC were produced by direct compression. Owing to the lamellar structure, FCC
was able to overcome the limitation of insufficient hardness during the production of highly porous
ODTs. These findings could revolutionize the production of ODTs and hence open up new vistas.
To protect the valuable findings, a patent was applied for the production of ODTs made of FCC.
The characterization of co-processed FCC revealed a promising new pharmaceutical excipient with a
broad range of applicability. Applicability of FCC seems to be of particular interest for formulations
that are characterized by high porosity, high tensile strength, or both. This is the case, amongst
others, for ODTs, carriers, adsorbents, floating tablets, effervescent tablets, controlled-released
formulations, ultra hard tablet (UHT), and cushioning agents.