Novel pH-Responsive PSS-Loaded Chitosan Matrix Nanoparticles Ameliorate Pressure Overload-Induced Cardiac Hypertrophy.

Cardiac hypertrophy is a critical contributor to cardiac dysfunction and the development of heart failure, yet effective therapeutic strategies remain limited. Propylene glycol alginate sulfate sodium (PSS) is a marine sulfated polysaccharide drug used in the treatment of cardiovascular diseases and has shown cardiac function benefits. Here, we designed a pH-responsive PSS-loaded nanoparticle drug delivery system. It was self-assembled by negatively charged PSS with positively charged trimethyl chitosan glycocholic acid (TMC-GA) via electrostatic interaction, and further stabilized the nanoparticles with Hydroxypropyl methylcellulose phthalate (HP55) excipients. The prepared TMC-GA/HP55@PSS nanoparticles were spherical, with a mean particle size of 361.5 ± 1.26 nm, zeta potential of -30.3 ± 0.9 mV, and encapsulation efficiency of 92.52 ± 2.4%. In vitro release study demonstrated the pH-responsive property of TMC-GA/HP55@PSS under intestinal conditions and facilitated nanoparticles absorption in the intestinal epithelium. In vitro experiments confirmed the biocompatibility of PSS and its ability to improve myocardial cell hypertrophy. In vivo, both PSS and its nanoparticles significantly ameliorated pressure overload-induced cardiac hypertrophy in mice, with TMC-GA/HP55@PSS exhibiting better cardioprotective efficacy. This study is the first to integrate pH-responsiveness and bile acid transport-mediated uptake into PSS nanocarrier systems. The findings provide valuable data and enlightenment for designing novel formulations and expanding the clinical applications of PSS.