Introduction

One of the main challenges in successfully using nanoparticles for drug delivery and biomedical imaging is overcoming biological barriers, especially the Mononuclear Phagocytic System (MPS). Any nanoparticles, regardless of its material composition and physio- chemical properties, is subject to recognition, uptake and, eventually, removal from the blood stream by the MPS. This occurs mostly in the liver and spleen, where a high abundance of macrophages resides. Various methods including PEGylation, Discoidal Polymeric Nanoconstructs, and empty vectors have been used to overcome MPS detection. Most recently methods aiming at temporarily disabling the macrophages, especially the Kupffer cells, have been investigated in order to allow the nanoparticles to reach the targeted site by eluding detection.

Technical features

Nanoparticles, ranging between 180 nm and 240 nm in diameter, carrying methyl palmitate and at least one serum globular protein (albumin, plasmin, transferrin, haemoglobin, or ferritin) have been designed to temporarily and reversibly disable the uptake function of macrophages. By inhibiting the macrophages activity, preferably intravenously, the nanoparticles can deliver the active or imaging agent to the biological target, which may be a cancerous lesion, vascular plaque, blood clot, edematous tissue, inflamed tissue, etc. Furthermore, these nanoparticles can be in the form of a cream, ointment, gel, suspension suitable for administration by injection or spray, or as a lyophilized product for reconstitution before use with water or other suitable vehicles. Depending the nanoparticles route of administration, excipients and/or carriers such as preservatives, thickeners, antioxidants, emollients, moisturizers, natural or artificial fragrances, surfactants, may be loaded.

Possible Applications

• Medical imaging;
• Targeted therapeutic drug administration;
• Acute or chronic inflammation, scar formation, generation of fibrotic tissue, transplant rejection, atherosclerosis, cancer, wound healing;
• Cosmetic composition, for example for the prevention and treatment of scars.

Advantages

• Able to elude and cross the Mononuclear Phagocytic System;
• Immunomodulatory effect with no immunodepression;
• Safe, temporary and reversible process.