Design and pharmacodynamic evaluation of DPK-060 loaded Nanostructured lipid carrier embedded gel for dermal delivery: A novel approach in the treatment of atopic dermatitis.

DPK-060 is a synthetic, 17 amino acid peptide, structurally derived from the human protein kininogen. DPK-060 mainly acts by membrane disruption mechanism, thus demonstrating strong broad-spectrum antimicrobial activity against both gram-positive and gram-negative microbes, including methicillin-resistant S. aureus (MRSA) in-vitro and in-vivo. Apart from its antimicrobial effect, DPK-060 also possesses anti-inflammatory activity. In addition, DPK-060 has demonstrated positive results in phase II clinical trials in atopic dermatitis (AD) patients; but was not statistically conclusive due to the instability of DPK-060 as a drug substance in the formulation. Thus, the present investigation was aimed to assess and compare the efficacy of DPK-060 nanostructured lipid (NLC) based gel with conventional formulations (free DPK-060 gel and lotion) in AD mice animal models. DPK-060 loaded NLCs were formulated by meltemulsification technique and loaded into Carbopol 934 P gel and characterized for various physicochemical parameters such as particle size, zeta-potential, shape and surface morphology, rheological parameters, in-vitro drug release, cytotoxicity, cellular uptake, ex-vivo skin permeation/deposition, in-vitro antimicrobial activity, and proteolytic stability studies. NLCs exhibited 85 % encapsulation with 6.7 % loading efficacy, a size, and zeta potential of 128.6 nm and -22.5 mv, respectively. Additionally, DPK-060 NLC gel demonstrated controlled release and a better permeation profile in comparison to free DPK-060 gel and lotion. A substantial reduction in pro-inflammatory cytokines levels and improvement in AD lesions was achieved by DPK-060 NLC gel compared to free DPK-060 gel and lotion-based formulations. The present study confirms that DPK-060 NLC gel-based formulation can be an effective, safe, and novel alternative for the treatment of AD.