Quality by design-driven approach to develop a nanocarrier-based sulfasalazine topical system for rheumatoid...

This study was conducted to improve the transdermal delivery of sulfasalazine (SSZ) by encapsulating it into the nanostructured lipid carrier (NLC)-based gel products.

Sulfasalazine was loaded into NLCs through solvent diffusion evaporation method. Box-Behnken design (BBD) was used to optimize formulation variables such as lipid concentration, ethanol concentration, and ultrasonication time. The optimized NLCs were analyzed for particle size, polydispersity index (PDI), and entrapment efficiency (%EE), and then morphological analysis was performed using scanning electronic microscopy (SEM). The NLC dispersion was added to a 1% gel base of Carbopol 934. The developed gel formulation was assessed for its in vitro release, ex vivo skin permeation, and anti-inflammatory activity (BSA protein denaturation assay).

Optimized SSZ-NLCs had a mean particle size of 112.5 nm, PDI of 0.090, and EE of 89%. SEM ensured spherical and uniform particle morphology. The SSZ-NLC gel exhibited higher drug release (∼65.17% in 24 h) compared to the SSZ-conventional gel (∼25.73%). The ex vivo permeation exhibited higher skin permeation than conventional gel. The anti-inflammatory studies indicated concentration-dependent suppression of BSA denaturation with 77.2% inhibition at 5000 μg/mL.

The developed gel formulation has shown desired characteristics to serve as a topical treatment of rheumatoid arthritis.