Introduction: Intravesical instillation is preferred over the systemic route of administration, as an efficient route of drug administration to treat bladder cancer. However, the periodic voiding of urine washes out the instilled drugs, eventually resulting in reduced drug exposure. Moreover, the presence of the bladder permeability barrier limits drug permeation into tumor tissues. It is therefore important to develop a novel delivery system that not only promotes prolonged retention of drugs in the bladder but also enables drugs to penetrate the barrier.
Areas covered: This review addresses the limitations of conventional therapeutic regimens and reports the use of polymeric hydrogels and nano/microcarriers for enhanced intravesical drug delivery in bladder cancer. Strategies to prolong residence time in the bladder and enhance cell penetration and target-cell specificity are discussed.
Expert opinion: Although promising results have been obtained in the field of intravesical drug delivery, numerous questions remain unanswered in terms of therapeutic efficacy. Specialized function covering extended drug exposure and/or enhanced drug uptake should be considered. Assessment protocols that adequately mimic the human bladder environment in vitro and in vivo experiments are needed to expedite formulation development.
Keywords: Bladder cancer; bladder retention; cell uptake; hydrogel; intravesical drug delivery; nanocarrier; target ligand.