Mucoadhesive Emulsion Microgels for Intravesical Drug Delivery: Preparation, Retention at Urothelium, and Biodistribution Study

Abstract

The intravesical instillation procedure is a proven method in modern urology for the treatment of bladder diseases. However, the low therapeutic efficiency and painfulness of the instillation procedure are significant limitations of this method. In the present study, we propose an approach to solving this problem by using microsized mucoadhesive macromolecular carriers based on whey protein isolate with the possibility of prolonged release of drugs as a drug delivery system. The optimal water-to-oil ratio (1:3) and whey protein isolate concentration (5%) were determined to obtain emulsion microgels with sufficient loading efficiency and mucoadhesive properties. The droplet diameter of emulsion microgels varies from 2.2 to 3.8 μm. The drug release kinetics from the emulsion microgels was evaluated. The release of the model dye in saline and artificial urine in vitro was observed for 96 h and reached up to 70% of loaded cargo for samples. The effect of emulsion microgels on the morphology and viability of two cell lines was observed: L929 mouse fibroblasts (normal adherent cells) and THP-1 human monocytes (cancer suspension cells). Developed emulsion microgels (5%, 1:3 and 1:5) showed sufficient mucoadhesion to a porcine bladder urothelium ex vivo. The biodistribution of emulsion microgels (5%, 1:3 and 1:5) in mice (n = 3) after intravesical (instillation) and systemic (intravenous) administration was assessed in vivo and ex vivo using nearinfrared fluorescence live imaging for real time. It was demonstrated that intravesical instillation allows approximately 10 times more efficient accumulation of emulsion microgels in the mice urinary bladder in vivo 1 h after injection compared to systemic injection. The retention of the emulsion of mucoadhesive microgels in bladders after the intravesical instillation was observed for 24 h.

Local Drug Delivery in Bladder Cancer: Advances of Nano/Micro/Macroscale Drug Delivery Systems

“…The microemulsion form yielded an increase in the penetration depth in bladder tissue from 60 to 120 µm compared to the free drug solutions. Emulsion microgels stabilized with whey protein isolate showed good mucoadhesion to the bladder urothelium, and their retention in the bladder after intravesical instillation was observed for 24 h [57]. M.S.…”

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

“…The microemulsion form yielded an increase in the penetration depth in bladder tissue from 60 to 120 μm compared to the free drug solutions. Emulsion microgels stabilized with whey protein isolate showed good mucoadhesion to the bladder urothelium, and their retention in the bladder after intravesical instillation was observed for 24 h [ 57 ]. M.S.…”

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

“…In recent years, many novel IDDs have been developed based on polymeric hydrogels, − microgels, , liposomes, polymer-drug conjugates, , nanoparticles, − nanogels, − and micelles − and shown great potential as therapeutic platforms for BC. Nanogels are three-dimensional structural hydrogels with nanoscale size ranges (typically less than 200 nm) formed by physically or chemically cross-linked polymers. , Nanogels exhibit distinctive features as nanocarriers for the application of BC therapy, such as high structural tunability and stability, good biocompatibility, facilitated delivery of multiple drugs with high loading efficiency, enhanced drug stability and efficacy, spatial and temporal drug release, and improved diffusion of drugs across bladder permeation barrier .…”