**4. Conclusions**

New liquisolid-tablet formulations of GLY, based on the use of a mesoporous clay (Neusilin®US2) or silica (Aeroperl®300), were successfully developed.

Both the selected mesoporous clay and silica, in virtue of their very marked adsorbent power joined to excellent flow and compactability properties, allowed to replace the use of combinations of carrier and coating materials, which are instead commonly employed for the preparation of conventional liquisolid systems.

The use of 2-PYR and DMA as very powerful solvents towards GLY (never employed before, to the best of our knowledge, in liquisolid formulations), enabled to strongly reduce the solvent volume necessary (0.05 mL) to completely dissolve the drug therapeutic dose (5 mg). Moreover, the selected highly-porous clay (Neusilin®US2) and silica (Aeroperl®300) enabled a high liquid load factor (1.1), because of their small amount necessary to convert drug solutions into well-flowable powders.

All the obtained liquisolid-tablets exhibited satisfying technological properties and exhibited a marked improvement of GLY dissolution properties, allowing in all cases to overcome 90% of dissolved drug after 60 min, with respect to only 40% obtained with the reference formulation containing the plain drug. However, the mesoporous clay Neusilin®US2 showed a superior performance with respect to the mesoporous silica Aeroperl®300 since it allowed to obtain tablets with more suitable technological properties.

The improved GLY dissolution behavior was attributed to its increased wetting properties and surface area, in virtue of its solubilization or almost molecular dispersion within the liquisolid matrix, as confirmed by DSC and PXRD studies.

In conclusion, the proposed strategy offers the benefits not only of simplifying the liquisolid formulation development, reducing the number of components, but also, and above all, of considerably increasing the liquid loading capacity, thus strongly reducing the amount of adsorbent material necessary to obtain dry-looking, freely-flowing powders, and ultimately decreasing the final tablet weight. Finally, simplicity, ease of handling, high cost-effectiveness of the proposed approach, make it particularly advisable for a possible industrial scale-up.

**Author Contributions:** Conceptualization, M.C., P.M. and M.V.; methodology, M.V.; formal analysis, M.C., P.M., and L.B.; investigation, L.B.; resources, M.V.; data curation, M.C., P.M., and L.B.; writing–original draft preparation, P.M.; writing–review and editing, P.M. and M.C.; supervision, M.V.; project administration, M.V.; All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
