Drug-Phospholipid Complex-loaded Matrix Film Formulation for the Enhanced Transdermal Delivery of Quercetin

A novel quercetin-phospholipid-complex (QPLC)-loaded matrix film for improved transdermal delivery of quercetin was developed. QPLC formulation, prepared using a solvent-evaporation method was optimized using a central-composite design. The optimized QPLC formulation was characterized by particle size and zeta potential analysis, thermal analysis, Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance spectroscopy (1H-NMR). QPLC formulation was functionally evaluated for solubility and in vitro dissolution of quercetin. Matrix films of pure quercetin (Q-MF) or QPLC (QPLC-MF) were prepared using a solvent casting method. The prepared Q-MF and QPLC-MF were characterized for weight uniformity, folding endurance, moisture content, and moisture uptake. The films were also functionally characterized for in vitro diffusion of quercetin through a dialysis membrane and ex vivo permeability of quercetin across rat skin. Finally, the anti-inflammatory activity of the films was evaluated on carrageenan-induced paw edema in Wistar albino rats. The experimental design identified the optimal formulation and process variables for the preparation of QPLC. The validation of the obtained model using these values confirmed the suitability and robustness of the model. The physical-chemical characterization of the prepared QPLC supported the formation of a stable complex. The solubility analysis of QPLC showed a 22-fold increase in quercetin aqueous solubility, compared to pure quercetin. The dissolution results exhibited a significantly higher rate and extent of quercetin dissolution from QPLC compared to that of pure quercetin. The permeability of quercetin from Q-MF and QPLC-MF across rat skin mirrored those obtained from the dissolution studies. Topical application of QPLC-MF exhibited a significant (p