**6. Conclusions**

Intravesical instillation using liposomes to encapsulate BoNT-A proteins is a potential treatment option to treat functional bladder disorders such as OAB, IC/BPS, and bladder oversensitivity. Although current clinical data regarding liposomal BoNT-A instillation are still limited in terms of its clinical efficacy on OAB and IC/BPS, adverse events due to intravesical BoNT-A injection can be avoided. With the future adjustment of the dose of BoNT-A, an increase in the instillation duration, and pretreatment with low-energy shock waves, liposome plus BoNT-A might play an important role in the treatment of bladder oversensitivity, OAB, and IC/BPS refractory to conventional medication.

**Author Contributions:** F.-C.H.: literature search and manuscript writing, H.-C.K.: critical comments and manuscript rearrangement. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was supported by the gran<sup>t</sup> from the Buddhist Tzu Chi Medical Foundation TCMF-MP-110-03-01.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

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