**4. Conclusions**

From the results that were obtained in this study, it is possible to state that the complexation of DAS with HP-β-CD is successful both in solution and in the solid state. In particular, the presence of the cyclodextrin allows for obtaining an increase in the drug water solubility and a favorable dissolution profile especially at pH 7.4 as compared to the non-complexed drug Moreover, cytotoxicity studies highlight that DAS complexation with HP-β-CD increases the cytotoxicity of the drug and PK results of a one-week pilot study with DAS/HP-β-CD inclusion complex in WT mice provided the basis for further long-term in vivo treatment with this new oral formulation of DAS in treadmill-exercised *mdx* mice.

In conclusion, this new inclusion complex could allow the development of a liquid formulation to be administered orally, which could be a valid alternative to the one currently present on the market that is solid, especially in the case of an administration in paediatric age. Moreover, considering that HP-β-CD is FDA approved for parenteral formulations, the DAS/HP-β-CD inclusion complex could also be an interesting tool for the administration of DAS by this route.

**Author Contributions:** Conceptualization, A.D.L. and N.D.; methodology, A.C. and F.S.; software, V.L.; validation, N.D., A.L. (Angela Lopedota) and M.F.; formal analysis, A.L. (Antonio Lopalco); investigation, V.L., B.B., P.M. and A.L. (Antonio Lopalco); resources, A.L. (Angela Lopedota) and M.F.; data curation, A.C. and F.S.; writing—original draft preparation, A.C. and F.S.; writing—review and editing, A.C. and F.S.; visualization, A.C., F.S and A.L. (Antonio Lopalco); supervision, A.D.L. and N.D.; project administration, N.D.; funding acquisition, A.D.L.

**Funding:** The University of Bari (Italy), and the Inter-University Consortium for Research on the Chemistry of Metal Ions in Biological Systems (C.I.R.C.M.S.B.) are gratefully acknowledged. This research has been supported by PRIN-MIUR (Research Project of National Interest—Ministry of Education, University and Research) project no. 20108YB5W3\_004. This work has been supported also by a gran<sup>t</sup> to ADL from Dutch Duchenne Parent Project (NL\_DPP) 2015, entitled "Preclinical studies to validate cSrc tyrosine kinase as therapeutic target in Duchenne muscular dystrophy".

**Acknowledgments:** We thank Antonio Palermo for his skillful technical assistance.

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