Nanocarriers, such as micelles, liposomes, polymeric nanoparticles and inorganic nanoparticles are promising tools for controlled drug delivery or imaging in cancer therapy and many other applications. Up to date, a number of nanocarriers have been approved for clinical treatment of a variety of therapeutics. Our enormous knowledge, advanced skills and excellent capabilities will provide you with the most optimized synthesis route, the PEGylated products with the best quality, and offer you a value-added service to meet development needs.
Fig. 1 Schematic representation of different nanocarriers with the PEG-exposed surface. (Journal of controlled release 2014, 192, 67-81)
PEGylation of Polymeric Nanoparticles
Fig.2 Schematic diagram of formation of PEGylated lecithin-chitosan nanoparticle. (AAPS PharmSciTech 2020, 21 (7), 285)
Biodegradable polymeric nanoparticles have many advantages for drug delivery, such as controlled release and targeting. However, after intravenous administration of polymeric nanoparticles, they will be cleared by the endothelial reticulum system within a few seconds or minutes. In order to overcome this shortcoming, hydrophilic PEG is introduced to modify the polymer. The introduction of PEG will not only affect the biodegradation behavior of nanoparticles, but also affect the release and distribution of drugs in the body. Polymeric nanoparticles are usually PEGylated by (1) physical surface coverage with PEG or PEG derivatives, (2) preparation of nanoparticles with PEG block co-polymers and (3) grafting PEG onto the nanoparticles surface.
PEGylation of Inorganic Nanoparticles
Fig.3 Schematic illustration of the function of PEG to prevent uptake by the reticuloendothelial system. (Nanomedicine 2011, 6 (4), 715-728.)
Inorganic nanoparticles made of calcium phosphate, gold, silica and iron oxide are preferred for drug delivery due to ease of preparation and uniform size and amenability for surface functionalization. However, these are less stable and could be toxic in biological systems. Therefore, in order to improve the biological stability and biocompatibility, surface modification has been carried out with PEG.
PEGylation of Liposomes
Fig.4 Schematic diagram of PEGylated liposome.
Liposome is an ideal drug delivery carrier. It has targeted properties, longer blood retention time and higher organ distribution selectivity, can improve the efficacy of drugs and reduce toxic side effects. Ordinary liposomes have the disadvantage of being easily cleared from the systemic circulation by liver and spleen macrophages. In this case, PEGylation can solve the above shortcomings, making liposomes stay in the blood for a longer time and increasing the passive targeting function of drugs. Moreover, it is simple to prepare PEG-phospholipid derivatives in advance, which has become the current research focus of PEGylation technique.
PEGylation of Micelles
Fig.5 Schematic representation of the micelle formation using heterobifunctional PEG and PEG derivatives. (Advanced drug delivery reviews 2003, 55 (3), 403-419)
Micelles are frequently preferred choice for anticancer drug delivery. Preparation of PEGylated micelles mostly utilizes PEGylated polymers or lipids through synthetic approaches. Block copolymer micelles with PEG coronas have emerged as systems with great potential in drug delivery, as they combine biocompatibility with the synthetic versatility of PEG. A variety of activated PEGs can be used exploited for these systems, such as block copolymer structures, providing control over the type and stability of covalent. linkage formed.
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