Enhanced transdermal delivery of lornoxicam by nanostructured lipid carrier gels modified with polyarginine peptide for treatment of carrageenan-induced rat paw edema

Background: Nanostructured lipid carriers (NLCs) are emerging as attractive drug carriers in transdermal drug delivery. The surface modification of NLCs with cell-penetrating peptides (CPPs) can enhance the skin permeation of drugs. Purpose: The objective of the current study was to evaluate the ability of the cell-penetrating peptide (CPP) polyarginine to translocate NLCs loaded with lornoxicam (LN) into the skin layers and to evaluate its anti-inflammatory effect. Methods: The NLCs were prepared using an emulsion evaporation and low temperature solidification technique using glyceryl monostearates, triglycerides, DOGS-NTA-Ni lipids and surfactants, and then six histidine-tagged polyarginine containing 11 arginine (R11) peptides was modified on the surface of NLCs. Results: The developed NLCs formulated with LN and R11 (LN-NLC-R11) were incorporated into 2% HPMC gels. NLCs were prepared with a particle size of (121.81 +/- 3.61)-(145.72 +/- 4.78) nm, and the zeta potential decreased from (-30.30 +/- 2.07) to (-14.66 +/- 0.74) mV after the modification of R11 peptides. The encapsulation efficiency and drug loading were (74.61 +/- 1.13) % and (7.92 +/- 0.33) %, respectively, regardless of the surface modification. Cellular uptake assays using HaCaT cells suggested that the NLC modified with R11 (0.02%, w/w) significantly enhanced the cell internalization of nanoparticles relative to unmodified NLCs (P<0.05 or P<0.01). An in vitro skin permeation study showed better permeation-enhancing ability of R11 (0.02%, w/w) than that of other content (0.01% or 0.04%). In carrageenan-induced rat paw edema models, LN-NLC-R11 gels inhibited rat paw edema and the production of inflammatory cytokines compared with LN-NLC gels and LN gels (P<0.01). Conclusion: In our investigation, it was strongly demonstrated that the surface modification of NLC with R11 enhanced the translocation of LN across the skin, thereby alleviating inflammation.