Oral Delivery of Kidney Targeting Nanotherapeutics for Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited renal disorder. Although a variety of candidate drugs have been found to modulate cystogenesis in animal studies, results from clinical trials have often been unfavorable due to low renal bioavailability and drug-induced side effects. To mitigate this, nanoparticles can be designed to deliver drugs directly to the target organ to increase effective dose while limiting off-target side effects. Unfortunately, there are no kidney-targeted nanomedicines clinically available, and most of the existing FDA-approved nanoparticles require intravenous administration which is not suitable for ADPKD that require lifelong therapy. To address this, we developed an oral drug delivery system using chitosan nanoparticles (CS-NP) that were loaded with peptide amphiphile micelles carrying metformin (met), an ADPKD drug candidate (CS-KM-met). We previously showed that CS-NP can shield met in the gastrointestinal tract; thus, we hypothesized that CS-NP could also enhance bioavailability of kidney-targeting micelles (KMs) upon oral administration. Specifically, we measured the loading capacity of KM-met in CS-NP, evaluated the stability of CS-KM-met under acidic conditions that mimic the gastric environment, and measured in vitro therapeutic effects. Upon oral administration in C57BL/6J mice, CS-KM-met showed significantly greater bioavailability and accumulation in the kidneys as compared to KM-met without CS-NP or free met for up to 24 hours. As such, CS-KM-met showed enhanced therapeutic efficacy in vivo upon oral administration in PKD mice (Pkd1fl/fl; Pax8-rtTA; Tet-O-Cre) compared to KM-met only. Herein, we demonstrate the potential of an oral delivery nanoformulation for the treatment of chronic kidney diseases such as ADPKD for the first time.