Polyethylene glycol (PEG): a versatile polymer for pharmaceutical applications

Degradable poly(ethylene oxide) through metal-free copolymerization of ethylene oxide with l-lactide

A simple and convenient method for the preparation of degradable poly(ethylene oxide) (PEO) is presented in this work.

Adsorption and in vitro release study of curcumin form polyethyleneglycol functionalized multi walled carbon nanotube: kinetic and isotherm study

Polyethylene glycol functionalized with oxygenated multi-walled carbon nanotubes (O-PEG-MWCNTs) as an efficient nanomaterial for the in vitro adsorption/release of curcumin (CUR) anticancer agent. The synthesized material was morphologically characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and transmission electron microscopy. In addition, the CUR adsorption process was assessed with kinetic and isotherm models fitting well with pseudo-second order and Langmuir isotherms. The results showed that the proposed O-PEG-MWCNTs has a high adsorption capacity for CUR (2.0 × 10³ mg/g) based on the Langmuir model. The in vitro release of CUR from O-PEG-MWCNTs was studied in simulating human body fluids with different pHs (ABS pH 5, intestinal fluid pH 6.6 and body fluid pH 7.4). Lastly, to confirm the success compliance of the O-PEG-MWCNT nanocomposite as a drug delivery system, the parameters affecting the CUR release such as temperature and PEG content were investigated. As a result, the proposed nanocomposite could be used as an efficient carrier for CUR delivery with an enhanced prolonged release property. Graphical Abstract ᅟ.

Mixing Poly(ethylene glycol) and Poly(2-alkyl-2-oxazoline)s Enhances Hydration and Viscoelasticity of Polymer Brushes and Determines Their Nanotribological and Antifouling Properties

Poly(2-alkyl-2-oxazoline)s (PAOXAs) have progressively emerged as suitable alternatives for replacing poly(ethylene glycol) (PEG) in a variety of biomaterial-related applications, especially in the designing of polymer brush-based biointerfaces because of their stealth properties and chemical robustness. When equimolar mixtures of PEG and PAOXAs are assembled on surfaces to yield mixed polymer brushes, the interfacial physicochemical properties of the obtained films are significantly altered, in some cases, surpassing the biopassive and lubricious characteristics displayed by single-component PAOXA and PEG counterparts. With a combination of variable angle spectroscopic ellipsometry, quartz crystal microbalance with dissipation, and atomic force microscopy-based methods, we demonstrate that mixing of PEG brushes with equimolar amounts of PAOXA grafts determines an increment in film's hydration and viscoelasticity. In the case of mixtures of PEG and poly(2-methyl-2-oxazoline) or poly(2-ethyl-2-oxazoline), brushes displaying full inertness toward serum proteins and improved lubricity with respect to the corresponding single-component layers can be generated, while providing a multifunctional surface that substantially enlarges the applicability of the designed coatings.

Poly(ethylene glycol) induces cell toxicity in melanoma cells by producing a hyperosmotic extracellular medium

Poly(ethylene glycol) is a polymer that is widely used as a biomaterial and has been approved in a host of applications. While generally viewed as inert, recent studies with poly(ethylene glycol) suggest that it may have some effects on cells and tissues, making it potentially attractive as a therapeutic agent. In this study, the effect of poly(ethylene glycol) on the cell viability, membrane transport and apoptotic markers of metastatic melanoma cells was examined. The data were combined with observed effects of the polymer on the cell media, including osmolality and viscosity, in order to elucidate any structure-function relationship between the polymer and cells. It was observed that poly(ethylene glycol) reduced the cellular viability of A375 cells, and that the effect was dependent on poly(ethylene glycol) molecular weight and concentration. The mechanism was highly correlated with changes in the osmolality of the cell medium, which is determined by the inherent structure of poly(ethylene glycol), and in particular the ethylene oxide units. This mechanism was specific to poly(ethylene glycol) and was not observed with the similar linear, hydrophilic polymer poly(vinyl pyrrolidone). Overall, the data suggest that poly(ethylene glycol) and poly(ethylene glycol)-like compounds have a distinct effect on cellular activity, presumably mediated in part by their osmotic effects, supporting the further investigation of these polymers as pharmaceutically active compounds.

Molecular self-assembly of copolymer from renewable phenols: new class of antimicrobial ointment base

Ointments are highly viscous forms intended for external applications either medicated or non-medicated means. Formulation of ointment depends upon the base ingredients to measure the viscosity difference. Several limitations of ointment bases has been encountered timely as agglomeration, oil phase ingredients can form lumps, poor dispersion, poor drug delivery efficiency, make stained, immiscible, and difficult to wash off. Therefore, it is necessary to make a new type of ointment bases that can overcome those limitations. This review summarizes a new type of ointment base preparation from the copolymer of renewable phenolic derivatives. The nanohydrogel preparation from these copolymers are especially effortless and highly efficient in drug delivery, exhibited versatile biological activities such as antioxidant, anti-inflammatory and wound healing in addition to antimicrobial property. Molecular self-assembly mechanisms have been addressed for nanogel formulation. The strategy makes a significant value in health-care application and be supposed to come marketed soon.

Smartly Engineered PEGylated Di-Block Nanopolymeric Micelles: Duo Delivery of Isoniazid and Rifampicin Against Mycobacterium tuberculosis

In an attempt to deliver multiple drugs through a nanoparticulate platform, the present study was designed to deliver isoniazid (INH) and rifampicin (RMP) together through conjugation/encapsulation approaches using PEG-PLA (polyethylene glycol-poly-L-lactic acid) polymeric micelles. The objective of this study is to identify the preparation and evaluation of PEGylated polymeric micelles with dual drug delivery of INH and RMP for the effective treatment of tuberculosis (TB). Synthesized PEG-PLA di-block-copolymer was further conjugated to INH-forming PEG-PLA-INH (PPI) conjugate. Separately, these conjugates were loaded with RMP building the rifampicin-loaded PEG-PLA-INH polymeric micelles (PMC). The critical micelle concentration (CMC) for the PEG-PLA copolymer was found to be 8.9 ± 0.96 mg/L, and the size and zeta potential were observed to be 187.9 ± 2.68 nm and - 8.15 ± 1.24 mV (0.251 ± 0.042 pdi), respectively. Percent drug loading of PMC was 16.66 ± 1.52 and 23.07 ± 1.05 with entrapment efficiency of 72.30 ± 3.49 and 78.60 ± 2.67% for RMP and INH, respectively. RBC hemolysis capacity of PMC was significantly less than pure RMP and INH. Microplate Alamar blue assay (MABA) along with microscopy showed that the nanoconstructed PMC were more effective than the drugs, and approximately 8-fold reduction in overall minimum inhibitory concentration (MIC) was observed. The prepared duo drug-loaded nano-engineered polymeric micelles were highly effective against sensitive Mycobacterium tuberculosis strains and found to be less hemolytic in nature. The micelles could be further explored (in the future) for in vivo anti-TB studies to establish further to achieve better treatment for TB.

Hydrazone-Linkage-Based Self-Healing and Injectable Xanthan-Poly(ethylene glycol) Hydrogels for Controlled Drug Release and 3D Cell Culture

Polymeric hydrogels have been extensively explored for controlled drug-delivery applications, but there is an increasing demand for smart drug delivery combined with tunable physicochemical attributes and tissue engineering potential. In this work, novel xanthan-poly(ethylene glycol) (PEG) hydrogels were developed by cross-linking polysaccharide, oxidized xanthan, and 8-arm PEG hydrazine through dynamic, pH-responsive, and biodegradable hydrazone linkages. Aqueous solutions (pH 6.5) of oxidized xanthan and PEG hydrazine were mixed together at 37 °C to obtain hydrogels within minutes, and the formation of hydrazone linkages was ascertained using Fourier transform infrared spectroscopy. Fabrication of xanthan-PEG hydrogels using hydrazone linkages has not been reported previously. The 3% hydrogels exhibited the storage modulus of 194 Pa, which increased to 770 Pa for 5% hydrogels. When subjected to alternating cycles of varying strains of 1 and 800% (5 cycles), hydrogels demonstrated instant recovery each time the extreme strain was relieved, thus suggesting excellent self-healing capabilities. Doxorubicin (DOX), chemotherapeutic agent, was loaded onto hydrogels, and release studies were carried out at pH 5.5 (tumoral) and 7.4 (physiological). The cumulative release from 3, 4, and 5% hydrogels at pH 5.5 was 81.06, 61.98, and 41.67%, whereas the release at pH 7.4 was 47.43, 37.01, and 35.34% at 30 days. MTT assay showed that oxidized xanthan and PEG hydrazine are not toxic to mammalian cells (NIH-3T3), as the cell viabilities were found to be 84.66 and 102% for concentrations up to 1 mg/mL. The live/dead assay with encapsulated NIH-3T3 cells showed no significant dead cell population, suggesting excellent compatibility of hydrogels in 2D and 3D culture. DOX-loaded hydrogels exhibited cytotoxicity against A549 cells when exposed to media released from hydrogels. Overall, hydrogels developed in this work may have potential applications in drug delivery and 3D cell culture for cell delivery.

Multifunctional polymer coatings for titanium implants

The aim of this work was to modify the surface of the titanium implants by application of multifunctional polymer coatings based on polyurethane and its composites with graphene and β-TCP. Graphene was used as an antibacterial agent, TCP as a bioactive component, and polymer coating as a corrosion protection of metal. As a result, materials with different surface characteristic, from hydrophilic to hydrophobic, varying in bioactivity and biocompatibility, were obtained. Wettability of the materials was tested by the sessile drop method; surface roughness was assessed on the basis of R_a parameter, measured by contact profilometry. The surface characteristic was complemented by microhardness testing. Also, in vitro immersion tests in fluids and cell tests were performed. Obtained results suggest that it is possible to fabricate, on the surface of titanium implants, multifunctional composite coatings based on polyurethane, with optimal composition for bone surgery and dentistry applications. The study further showed that the chemical structure (composition) of the polymer and the graphene content are crucial in terms of biocompatibility of the final material, while addition of tricalcium phosphate affects its bioactivity.

Ice Recrystallization Inhibiting Polymers Enable Glycerol-Free Cryopreservation of Microorganisms

All modern molecular biology and microbiology is underpinned by not only the tools to handle and manipulate microorganisms but also those to store, bank, and transport them. Glycerol is the current gold-standard cryoprotectant, but it is intrinsically toxic to most microorganisms: only a fraction of cells survive freezing and the presence of glycerol can impact downstream applications and assays. Extremophile organisms survive repeated freeze/thaw cycles by producing antifreeze proteins which are potent ice recrystallization inhibitors. Here we introduce a new concept for the storage/transport of microorganisms by using ice recrystallization inhibiting poly(vinyl alcohol) in tandem with poly(ethylene glycol). This cryopreserving formulation is shown to result in a 4-fold increase in E. coli yield post-thaw, compared to glycerol, utilizing lower concentrations, and successful cryopreservation shown as low as 1.1 wt % of additive. The mechanism of protection is demonstrated to be linked not only to inhibiting ice recrystallization (by comparison to a recombinant antifreeze protein) but also to the significantly lower toxicity of the polymers compared to glycerol. Optimized formulations are presented and shown to be broadly applicable to the cryopreservation of a panel of Gram-negative, Gram-positive, and mycobacteria strains. This represents a step-change in how microorganisms will be stored by the design of new macromolecular ice growth inhibitors; it should enable a transition from traditional solvent-based to macromolecular microbiology storage methods.

Poly(3-hydroxybutyrate)/poly(ethylene glycol) scaffolds with different microstructure: the effect on growth of mesenchymal stem cells

Development of biocompatible 3D scaffolds is one of the most important challenges in tissue engineering. In this study, we developed polymer scaffolds of different design and microstructure to study cell growth in them. To obtain scaffolds of various microstructure, e.g., size of pores, we used double- and one-stage leaching methods using porogens with selected size of crystals. A composite of poly(3-hydroxybutyrate) (PHB) with poly(ethylene glycol) (PEG) (PHB/PEG) was used as polymer biomaterial for scaffolds. The morphology of scaffolds was analyzed by scanning electron microscopy; the Young modulus of scaffolds was measured by rheometry. The ability to support growth of mesenchymal stem cells (MSCs) in scaffolds was studied using the XTT assay; the phenotype of MSC was preliminarily confirmed by flow cytometry and the activity of alkaline phosphatase and expression level of CD45 marker was studied to test possible MSC osteogenic differentiation. The obtained scaffolds had different microstructure: the scaffolds with uniform pore size of about 125 µm (normal pores) and 45 µm (small pores) and scaffolds with broadly distributed pores size from about 50-100 µm. It was shown that PHB/PEG scaffolds with uniform pores of normal size did not support MSCs growth probably due to their marked spontaneous osteogenic differentiation in these scaffolds, whereas PHB/PEG scaffolds with diverse pore size promoted stem cells growth that was not accompanied by pronounced differentiation. In scaffolds with small pores (about 45 µm), the growth of MSC was the lowest and cell growth suppression was only partially related to stem cells differentiation. Thus, apparently, the broadly distributed pore size of PHB/PEG scaffolds promoted MSC growth in them, whereas uniform size of scaffold pores stimulated MSC osteogenic differentiation.

Drug-gut microbiota interactions: implications for neuropharmacology

The fate and activity of drugs are frequently dictated not only by the host per se but also by the microorganisms present in the gastrointestinal tract. The gut microbiome is known to, both directly and indirectly, affect drug metabolism. More evidence now hints at the effects that drugs can have on the function and composition of the gut microbiome. Both microbiota-mediated alterations in drug metabolism and drug-mediated alterations in the gut microbiome can have beneficial or detrimental effects on the host. Greater insights into the mechanisms driving these reciprocal drug-gut microbiota interactions are needed to guide the development of microbiome-targeted dietary or pharmacological interventions, which may have the potential to enhance drug efficacy or reduce drug side effects. In this review, we explore the relationship between drugs and the gut microbiome, with a specific focus on potential mechanisms underpinning the drug-mediated alterations on the gut microbiome and the potential implications for psychoactive drugs. LINKED ARTICLES: This article is part of a themed section on When Pharmacology Meets the Microbiome: New Targets for Therapeutics? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.24/issuetoc.

Effects of PCL, PEG and PLGA polymers on curcumin release from calcium phosphate matrix for in vitro and in vivo bone regeneration

Calcium phosphate materials are widely used as bone-like scaffolds or coating for metallic hip and knee implants due to their excellent biocompatibility, compositional similarity to natural bone and controllable bioresorbability. Local delivery of drugs or osteogenic factors from scaffolds and implants are required over a desired period of time for an effectual treatment of various musculoskeletal disorders. Curcumin, an antioxidant and anti-inflammatory molecule, enhances osteoblastc activity in addition to its anti-osteoclastic activity. However, due to its poor solubility and high intestinal liver metabolism, it showed limited oral efficacy in various preclinical and clinical studies. To enhance its bioavailability and to provide higher release, we have used poly (ε-caprolactone) (PCL), poly ethylene glycol (PEG) and poly lactide co glycolide (PLGA) as the polymeric system to enable continuous release of curcumin from the hydroxyapatite matrix for 22 days. Additionally, curcumin was incorporated in plasma sprayed hydroxyapatite coated Ti6Al4V substrate to study in vitro cell material interaction using human fetal osteoblast (hFOB) cells for load bearing implants. MTT cell viability assay and morphological characterization by FESEM showed highest cell viability with samples coated with curcumin-PCL-PEG. Finally, 3D printed interconnected macro porous β-TCP scaffolds were prepared and curcumin-PCL-PEG was loaded to assess the effects of curcumin on in vivo bone regeneration. The presence of curcumin in TCP results in enhanced bone formation after 6 weeks. Complete mineralized bone formation increased from 29.6 % to 44.9% in curcumin-coated scaffolds compared to pure TCP. Results show that local release of curcumin can be designed for both load bearing or non-load bearing implants with the aid of polymers, which can be considered an excellent candidate for wound healing and tissue regeneration applications in bone tissue engineering.

Nanopharmaceuticals for wound healing - Lost in translation?

Today, many of the newly developed pharmaceuticals and medical devices take advantage of nanotechnology and with a rising incidence of chronic diseases such as diabetes and cardiovascular disease, the number of patients afflicted globally with non-healing wounds is growing. This has created a requirement for improved therapies and wound care. However, converting the strategies applied in early research into new products is still challenging. Many of them fail to comply with the market requirements. This review discusses the legal and scientific challenges in the design of nanomedicines for wound healing. Are they lost in translation or is there a new generation of therapeutics in the pipeline?

A switchable polymer brush system for antifouling and controlled detection

A stimuli-responsive polymer brush system is designed to switch on and off surface functionality and prevent functional groups from fouling by grafting together two polymer brushes with precisely controlled lengths. The polymer brush with functional groups has a fixed length, while the other brush extends and collapses as the environment changes.

Fabrication of surfactant-stabilized nanosuspension of naringenin to surpass its poor physiochemical properties and low oral bioavailability

BACKGROUND

Nanosuspension is a biphasic system consisting of native drug particles dispersed in an aqueous surfactant or polymeric solution with a particle size between 10 to 1000 nm. In contrast to other drug delivery systems, nanosuspension offer the unique advantage of increasing solubility of the native drug resulting into faster drug absorption and hence achieving faster maximum plasma concentration.

HYPOTHESIS/PURPOSE

The present study aims to evaluate surfactants/polymer stabilized nanosuspensions of naringenin (NN), a phytomedicine, to surpass its poor physiochemical properties and low oral bioavailability.

STUDY DESIGN

Optimization and characterization (DLS, SEM, PXRD and DSC) of nanosuspensions followed by in-vitro drug dissolution studies and pharmacokinetic study in male Sprague-Dawley rats were performed.

METHODS

Nanosuspensions were prepared by precipitation-ultrasonication method with varying concentrations of different surfactants and polymer such as sodium cholate (SC), sodium lauryl sulphate (SLS), poly ethylene glycol 4000 (PEG), polysorbate 80 (Tween^® 80), poloxomer-188 and D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS or Vitamin E-TPGS).

RESULTS

Nanosuspension prepared with 0.5% w/v d-α-Tocopherol polyethylene glycol 1000 succinate (TPNS) and 7.5 mg NN, showed the smallest size of 118.1 ± 2.7 nm. TPNS showed increase in drug dissolution in simulated gastric fluid pH 1.2 (SGF) and phosphate buffer pH 6.8 (PB). TPNS demonstrated an improved pharmacokinetic profile compared to pure NN resulting 2.14 and 3.76 folds increase in C_max and AUC, respectively. In addition, TPNS were stable over a period of six months.

CONCLUSION

The developed formulation strategy of nanosuspension could be exploited to improve the solubility and bio-availability of poorly soluble NN and other phytomedicines.

Peptide chemistry toolbox - Transforming natural peptides into peptide therapeutics

The development of solid phase peptide synthesis has released tremendous opportunities for using synthetic peptides in medicinal applications. In the last decades, peptide therapeutics became an emerging market in pharmaceutical industry. The need for synthetic strategies in order to improve peptidic properties, such as longer half-life, higher bioavailability, increased potency and efficiency is accordingly rising. In this mini-review, we present a toolbox of modifications in peptide chemistry for overcoming the main drawbacks during the transition from natural peptides to peptide therapeutics. Modifications at the level of the peptide backbone, amino acid side chains and higher orders of structures are described. Furthermore, we are discussing the future of peptide therapeutics development and their impact on the pharmaceutical market.

Lowering side effects of NSAID usage in osteoarthritis: recent attempts at minimizing dosage

INTRODUCTION

Osteoarthritis is a burdensome disease that causes progressive damage to articular cartilage. Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the preferred treatments for symptomatic relief. However, NSAIDs can cause serious dose-dependent side effects, which has prompted experts to recommend the minimization of NSAID dosage.

AREAS COVERED

This review focuses on three broad strategies that are currently being investigated or implemented to minimize NSAID dosage: nano-formulation, encapsulation, and topical delivery. The benefits, challenges and current status of these methods are discussed.

EXPERT OPINION

Multiple strategies are under investigation to lower NSAID dosage. There is great potential in developing formulations that utilize more than one of these strategies together. However, there are challenges to developing these lower dose preparations. In order to maximize the clinical potential of the abundance of NSAIDs that are both available and being developed, there is a major need for additional clinical studies directly comparing safety and efficacy of different preparations.

EGFR-targeting PLGA-PEG nanoparticles as a curcumin delivery system for breast cancer therapy

Poor bioavailability and non-specificity of chemotherapeutic agents are major challenges in breast cancer treatment. Antibodies and small molecules that block cell signaling pathways have shown promise in the clinic, but their application is also limited by the high costs and treatment dosages required. Novel therapies that aim to rapidly and specifically target malignant cells with long-lasting impact in the tumor microenvironment may ultimately improve clinical outcome in cancer patients. Here, we demonstrate that epidermal growth factor receptor (EGFR)-targeting GE11 peptides conjugated with PEGylated polylactic-co-glycolic acid (PLGA) nanoparticles can be used to effectively deliver an anti-cancer agent, curcumin, into EGFR-expressing MCF-7 cells in vitro and in vivo. Treatment of breast cancer cells and tumor-bearing mice with these curcumin-loaded nanoparticles gave rise to reduced phosphoinositide 3-kinase signaling, decreased cancer cell viability, attenuated drug clearance from the circulation, and suppressed tumor burden compared with free curcumin or non-EGFR targeting nanoparticles. The targeted nanoscale drug delivery system we describe here may provide a new strategy for the design of targeted cancer therapy vectors. Our study provides evidence that the efficacy of pharmacologic anti-cancer agents can be enhanced through their delivery in the form of modified nanoparticles that effectively target specific malignant cell types.

Characterization of pegylated and non-pegylated liposomal formulation for the delivery of hypoxia activated vinblastine-N-oxide for the treatment of solid tumors

Solid tumors often contain hypoxic regions which are resistant to standard chemotherapy and radiotherapy. We have developed a liposomal delivery system for a prodrug of vinblastine (CPD100) which converts to the parent compound only in the presence of lower oxygen levels. As a part of this work we have developed and optimized two formulations of CPD100: one composed of sphingomyelin/cholesterol (55/45; mol/mol) (CPD100Li) and the other composed of sphingomyelin/cholesterol/PEG (55/40/5; mol/mol) (CPD100 PEGLi). We evaluated the antiproliferative effect of CPD100 and the two formulations against A549 non-small lung cancer cell. A549 cell line showed to be sensitive to CPD100 and the two formulations displayed a higher hypoxic: air cytotoxicity ratio compared to the pro-drug. CPD100 elimination from the circulation after injection in mouse was characterized by a very short circulation time (~0.44h), lower area under the curve (AUC) (33μgh/mL) and high clearance (916mL/h/kg) and lower volume of distribution (17.4mL/kg).Total drug elimination from the circulation after the administration of liposomal formulation was characterized by prolonged circulation time (5.5h) along with increase in the AUC (56μgh/mL) for CPD100 Li and (9.5h) with AUC (170μgh/mL) for CPD100PEGLi. This was observed along with increase in volume of distribution and decrease in clearance for the liposomes. The systemic exposure of the free drug was much lower than that achieved with the liposomes. When evaluated for the efficacy in A549 xenograft model in mice, both the liposomes demonstrated excellent tumor suppression and reduction for 3months. The blood chemistry panel and the comprehensive blood analysis showed no increase or decrease in the markers and blood count. In summary, the pharmacokinetic analysis along with the efficacy data emphasis on how the delivery vehicle modifies and enhances the accumulation of the drug and at the same time the increased systemic exposure is not related to toxicity.

Ganglioside inserted into PEGylated liposome attenuates anti-PEG immunity

Despite the clinical introduction of a vast number of polyethylene glycol (PEG)-conjugated therapeutics, conjugated PEG is also known for an unfortunate inclination toward immunogenicity. Immunogenicity of PEG, manifested by the robust production of anti-PEG IgM, is known to compromise the therapeutic efficacy and/or reduce the tolerance of PEGylated therapeutics. In the present study, we inserted ganglioside into the membrane of PEGylated liposome (PL) to prepare ganglioside-modified PEGylated liposomes (G-PL), and investigated its efficacy in attenuating the anti-PEG IgM response against PL. A single intravenous injection of G-PL significantly attenuated the anti-PEG IgM production, compared with that of naïve PL. In addition, pretreatment with G-PL substantially alleviated the anti-PEG IgM response elicited by a subsequent dose of PL, presumably via inducing B cell tolerance, and as a consequence, this modification abrogated/attenuated the incidence of the rapid clearance of subsequently administrated PL. These results indicate that incorporating gangliosides in PEGylated liposome membrane not only prevents the immunogenicity of PEG but also induces the tolerance of B cells to subsequent doses of the immunogenic PL. Consequently, liposomal membrane modification with ganglioside might represent a promising approach to attenuating the immunogenicity of PEGylated liposomes while preserving their therapeutic efficacy, particularly upon repeated administration.

Analysis of individual block length of amphiphilic di- & tri-block copolymers containing poly(ethylene oxide) and poly(methyl methacrylate)

Estimation of individual block lengths and extent of homopolymers.