A comprehensive review on hydrogel materials in urology: Problems, methods, and new opportunities

Current and emerging strategies to curb antibiotic-resistant urinary tract infections

Rising rates of antibiotic resistance in uropathogenic bacteria compromise patient outcomes and prolong hospital stays. Consequently, new strategies are needed to prevent and control the spread of antibiotic resistance in uropathogenic bacteria. Over the past two decades, sizeable clinical efforts and research advances have changed urinary tract infection (UTI) treatment and prevention strategies to conserve antibiotic use. The emergence of antimicrobial stewardship, policies from national societies, and the development of new antimicrobials have shaped modern UTI practices. Future UTI management practices could be driven by the evolution of antimicrobial stewardship, improved and readily available diagnostics, and an improved understanding of how the microbiome affects UTI. Forthcoming UTI treatment and prevention strategies could employ novel bactericidal compounds, combinations of new and classic antimicrobials that enhance bacterial killing, medications that prevent bacterial attachment to uroepithelial cells, repurposing drugs, and vaccines to curtail the rising rates of antibiotic resistance in uropathogenic bacteria and improve outcomes in people with UTI.

Mucoadhesive Thiolated Hyaluronic Acid/Pluronic F127 Nanogel Formation via Thiol-Maleimide Click Reaction for Intravesical Drug Delivery

The development of nanocarriers to prolong the residence time and enhance the permeability of chemotherapeutic drugs on bladder mucosa is important in the postsurgery treatment of superficial bladder cancers (BCs). Here, the mucoadhesive HA-SH/PF127 nanogels composed of a temperature-sensitive Pluronic F127 (PF127) core and thiolated hyaluronic acid (HA-SH) shell were prepared by the emulsification/solvent evaporation method. The nanogels were constructed through the thiol-maleimide click reaction in the HA-SH aqueous side of the oil-water interface and self-oxidized cross-linking thiols between HA-SH. The HA-SH/PF127 nanogels prepared at different thiol-to-maleimide group molar ratios, water-to-oil volume ratios, and cross-linking reaction times were characterized regarding hydrodynamic diameter (Dh) and zeta potential (ζ), and the optimal formulation was obtained. The excellent mucoadhesive properties of the HA-SH/PF127 nanogels were evaluated by using the mucin particle method. Doxorubicin (DOX) was encapsulated in the PF127 core of DOX@HA-SH/PF127 nanogels with a high loading efficiency (87.5%) and sustained release from the nanogels in artificial urine. Ex vivo studies on porcine bladder mucosa showed that the DOX@HA-SH/PF127 nanogels enhanced the penetration of the DOX into the bladder mucosa without disrupting the mucus structure or the bladder tissue. A significant dose-dependent cytotoxic effect of DOX@HA-SH/PF127 nanogels on both T24 and MB49 cells was observed. The present study demonstrates that the mucoadhesive HA-SH/PF127 nanogels are a promising intravesical drug delivery system for superficial BC therapy.

Progress and challenges in intravesical drug delivery

INTRODUCTION

Intravesical drug delivery (IDD) has gained recognition as a viable approach for treating bladder-related diseases over the years. However, it comes with its set of challenges, including voiding difficulties and limitations in mucosal and epithelial penetration. These challenges lead to drug dilution and clearance, resulting in poor efficacy. Various strategies for drug delivery have been devised to overcome these issues, all aimed at optimizing drug delivery. Nevertheless, there has been minimal translation to clinical settings.

AREAS COVERED

This review provides a detailed description of IDD, including its history, advantages, and challenges. It also explores the physical barriers encountered in IDD, such as voiding, mucosal penetration, and epithelial penetration, and discusses current strategies for overcoming these challenges. Additionally, it offers a comprehensive roadmap for advancing IDD into clinical trials.

EXPERT OPINION

Physical bladder barriers and limitations of conventional treatments result in unsatisfactory efficacy against bladder diseases. Nevertheless, substantial recent efforts in this field have led to significant progress in overcoming these challenges and have raised important attributes for an optimal IDD system. However, there is still a lack of well-defined steps in the workflow to optimize the IDD system for clinical settings, and further research is required to establish more comprehensive in vitro and in vivo models to expedite clinical translation.

Local Drug Delivery in Bladder Cancer: Advances of Nano/Micro/Macro-Scale Drug Delivery Systems

Treatment of bladder cancer remains a critical unmet need and requires advanced approaches, particularly the development of local drug delivery systems. The physiology of the urinary bladder causes the main difficulties in the local treatment of bladder cancer: regular voiding prevents the maintenance of optimal concentration of the instilled drugs, while poor permeability of the urothelium limits the penetration of the drugs into the bladder wall. Therefore, great research efforts have been spent to overcome these hurdles, thereby improving the efficacy of available therapies. The explosive development of nanotechnology, polymer science, and related fields has contributed to the emergence of a number of nanostructured vehicles (nano- and micro-scale) applicable for intravesical drug delivery. Moreover, the engineering approach has facilitated the design of several macro-sized depot systems (centimeter scale) capable of remaining in the bladder for weeks and months. In this article, the main rationales and strategies for improved intravesical delivery are reviewed. Here, we focused on analysis of colloidal nano- and micro-sized drug carriers and indwelling macro-scale devices, which were evaluated for applicability in local therapy for bladder cancer in vivo.