Highlights

• This invention developed a sustained-release microsphere formulation based on S-propargyl-cysteine (SPRC), using a PLGA–gelatin composite carrier, constructed via the emulsion evaporation method.
• The formulation allows sustained SPRC release (7–30 days in vitro, 1–15 days in vivo), maintaining stable hydrogen sulfide generation and minimizing toxicity.
• Animal studies showed the formulation effectively alleviated paw swelling in rheumatoid arthritis model rats. Reduced dosing frequency to once every 3 days demonstrated excellent safety and therapeutic potential.

Summary

This invention patent presents the development of a sustained-release formulation for endogenous hydrogen sulfide (H₂S). Based on the pharmacological properties of S-propargyl-cysteine (SPRC) as an H₂S donor, the formulation is prepared using an emulsion evaporation method to produce core–shell structured drug-loaded microspheres.

The formulation uses PLGA (poly(lactic-co-glycolic acid)) as the carrier and gelatin as a release retardant, enabling the controlled and sustained release of SPRC, which maintains stable in vivo H₂S levels and avoids toxic side effects caused by rapid H₂S concentration spikes.

The microspheres exhibit high drug loading and encapsulation efficiency, and significantly reduce paw swelling and inflammation scores in rheumatoid arthritis (RA) model rats. Animal experiments demonstrated that the release duration of the drug can be extended beyond 7 days, reducing the dosing frequency to once every 3 days.

This sustained-release formulation of endogenous hydrogen sulfide provides a safe and effective new strategy for the treatment of rheumatoid arthritis, with significant clinical translation potential.

朱依谆, 余越, “Endogenous Hydrogen Sulfide Sustained-Release Formulation: Preparation Method and Application,” China Patent CN114246845A, Mar. 29, 2022.