# A Novel Drug Delivery System for the Treatment of Lupus Nephritis: From Delivery System Design and Optimization to Treatment

## TL;DR

This study develops a new drug delivery system combining two compounds to treat lupus nephritis, showing improved effectiveness and reduced inflammation in mice.

## Contribution

A self-nanoemulsifying drug delivery system co-loading TGP and DHA is designed and optimized for lupus nephritis treatment.

## Key findings

- The optimized SNEDDS achieved high drug loading and small particle size with low polydispersity.
- In mice, the treatment reduced urinary protein, autoantibodies, and inflammatory cytokines significantly.
- Renal tissue damage was also alleviated in the treated mice.

## Abstract

Lupus nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE), characterized by immune system disorders and multiple organ damage. Current clinical treatment of LN requires a complex multi-drug combination, which is often associated with severe side effects and low patient compliance. The aim of this study was to design a self-nanoemulsifying drug delivery system (SNEDDS) co-loading total glucosides of Paeonia (TGP) and dihydroartemisinin (DHA) to increase the solubility of the drug as well as achieve synergistic anti-inflammatory and immunomodulatory effects for LN therapy. Network pharmacology, molecular docking and molecular dynamics simulations were employed to predict the core therapeutic targets and related signaling pathways. The SNEDDS co-loaded with TGP and DHA was optimized via central composite design response surface methodology (CCD-RSM). Its physicochemical properties, particle size and the polydispersity index (PDI) of the optimized formulation were characterized. In vivo therapeutic efficacy was evaluated in MRL/lpr mice by measuring disease-related indicators (urinary protein, serum ANA, and anti-ds-DNA) and inflammatory cytokines (TNF-α, IL-6, and IL-1β). Renal tissue pathology was also examined. All data were analyzed by one-way analysis of variance (ANOVA) with p < 0.05 considered statistically significant. The core therapeutic targets predicted with high relevance were AKT1, MAPK1, MAPK3, and RELA. The optimized SNEDDS achieved a high loading capacity of 16.11 ± 0.43 mg/g for TGP and 12.79 ± 1.33 mg/g for DHA, with a particle size of (25.84 ± 0.30) nm and PDI of (0.07 ± 0.02). In MRL/lpr mice, SNEDDS treatment significantly reduced urinary protein levels (p < 0.01), serum ANA (p < 0.01) and anti-ds-DNA titers (p < 0.01) compared with the model group. Additionally, the levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) were markedly decreased (p < 0.05), and renal tissue damage was alleviated. Conclusions: The SNEDDS co-loaded TGP and DHA is a promising oral nanotherapeutic strategy for LN, offering synergistic anti-inflammatory and immunomodulatory effects.