Physiological blood-brain transport is impaired with age by a shift in transcytosis.

The vascular interface of the brain, known as the blood-brain barrier (BBB), is understood to maintain brain function in part via its low transcellular permeability1-3. Yet, recent studies have demonstrated that brain ageing is sensitive to circulatory proteins4,5. Thus, it is unclear whether permeability to individually injected exogenous tracers-as is standard in BBB studies-fully represents blood-to-brain transport. Here we label hundreds of proteins constituting the mouse blood plasma proteome, and upon their systemic administration, study the BBB with its physiological ligand. We find that plasma proteins readily permeate the healthy brain parenchyma, with transport maintained by BBB-specific transcriptional programmes. Unlike IgG antibody, plasma protein uptake diminishes in the aged brain, driven by an age-related shift in transport from ligand-specific receptor-mediated to non-specific caveolar transcytosis. This age-related shift occurs alongside a specific loss of pericyte coverage. Pharmacological inhibition of the age-upregulated phosphatase ALPL, a predicted negative regulator of transport, enhances brain uptake of therapeutically relevant transferrin, transferrin receptor antibody and plasma. These findings reveal the extent of physiological protein transcytosis to the healthy brain, a mechanism of widespread BBB dysfunction with age and a strategy for enhanced drug delivery.

Direct quantification of intact FIM in monkey plasma using a selective chromatography-tandem mass spectrometry method: Application in a pharmacokinetic study.

FIM protein, which consists of 155 amino acids, was developed as a novel GLP-1 analog to reduce blood glucose, and pharmacodynamic results showed that it had a certain effect when used in treating Alzheimer's disease. The molecular weight of FIM is 16,304 Da. In theory, the concentration of FIM in biological samples should be determined by the ligand binding assay method or indirectly quantified using LC-MS/MS instrumentation. However, the above methods are complex and time-consuming. In this study, we successfully developed a simpler LC-MS/MS method for directly quantifying the intact FIM protein in monkey plasma for the first time. The chromatographic separation of FIM was achieved using an InertSustain Bio C18 column with a mobile phase of acetonitrile containing 0.1% formic acid (A)-water containing 0.1% formic acid (B) at a flow rate of 0.3 ml/min. Good linearity was observed in the concentration range of 5-500 ng/ml (r2 > 0.99). The intra- and inter-day precisions (expressed as relative standard deviation, RSD) of FIM were 2.30-12.8 and 7.30-13.2%, respectively. The intra- and inter-day accuracies (expressed as a relative error, RE) were -12.7-6.55 and - 10.1-0.892%, respectively. This method was successfully applied for a pharmacokinetic study of the FIM protein in four monkeys after subcutaneous administration.

Clinical Pharmacology Review of Plasma-derived and Recombinant Protein Products: CBER Experience and Perspectives on Model-Informed Drug Development.

INTRODUCTION: Clinical pharmacology studies are one of the major types of regulatory data submitted for review of therapeutic proteins regulated by the Center for Biologics Evaluation and Research (CBER). AIM: The primary objective of the current study is to provide an overview of the role of clinical pharmacology including pharmacokinetics (PK), pharmacodynamics (PD) and exposure-response analysis at CBER. Furthermore, we aim to provide a baseline estimate for the use of quantitative clinical pharmacology studies prior to implementation of FDA's model-informed drug development (MIDD) pilot programme. METHODS: We survey original Biologics License Applications (BLAs) for plasma-derived and related recombinant therapeutic protein products approved by CBER/FDA (2008-2017). RESULTS: There were 37 original BLAs that met our inclusion criteria, and 34 of these products (92%) contained human PK data as part of the biological licensing. The products were broadly classified as coagulation factors (54%), IgG and related proteins (24%), and other therapeutic proteins (22%). Coagulation factor VIII and IX products constitute 32% of the BLAs and indicated for treatment of haemophilia A and B, respectively. Twelve products (35%) used model-based approaches (population PK/PD and exposure-response). Over the past 5 years (2013 to 2017), there is a trend for increased application of MIDD approaches as compared to the previous cohort years (2008 to 2012). CONCLUSION: In conclusion, clinical pharmacology has played a major role in regulatory review of plasma-derived products, and we expect that the application of quantitative methods will further evolve for these products under the FDA MIDD programme.

Determination of permeability, plasma protein binding, blood partitioning, pharmacokinetics and tissue distribution of Withanolide A in rats: A neuroprotective steroidal lactone.

Preclinical Research & Development Withanolide A (WA), a steroidal lactone is a major bioactive constituent of Withania somnifera (L.) with remarkable neuropharmacological activity. In this study, we investigated the permeability, plasma protein binding (PPB), blood partitioning, intravenous (i.v.), and oral pharmacokinetics as well as i.v. tissue distribution (TD) of pure WA in a rat model. The PPB, RBCs partitioning, and permeability of WA were determined by Ultra Performance Liquid Chromatography (UPLC) method. However, the pharmacokinetics and TD of WA were evaluated by validated and sensitive liquid chromatography coupled mass spectrometry (LC-ESI-MS/MS) method. The PPB and permeability of WA were determined by equilibrium dialysis and parallel artificial membrane permeability assay method, respectively. The results demonstrated that WA has high PPB and passive permeability. Furthermore, WA was found to have fast equilibration between RBCs and plasma. Following i.v. (2 mg/kg) and per-oral (25 mg/kg) administration of WA, the max concentration (Cmax ) in plasma was found as 85.53 ± 6.54 and 48.04 ±5.78 ng/mL, respectively. The TD study results indicated that WA has a rapid and wide TD. The maximum concentration in various tissues was found in following order: Clung > Cliver > Ckidney ≈ Cspleen > Cheart > Cbrain . The preclinical in vitro, as well as pharmacokinetics and TD results, are anticipated to support the future preclinical and clinical application of WA.

[Estimation of time detection limit for human cytochrome b in females of Lutzomyia evansi].

INTRODUCTION: Molecular biology techniques have allowed a better knowledge of sources of blood meals in vector insects. However, the usefulness of these techniques depends on both the quantity of ingested blood and the digestion process in the insect. OBJECTIVE: To identify the time limit for detection of the human cytochrome b (Cyt b) gene in experimentally fed females of Lutzomyia evansi. MATERIALS AND METHODS: Eight groups of L. evansi females were fed on human blood and sacrificed at intervals of 24 hours post-ingestion. Total DNA was extracted from each female and a segment of 358 bp of Cyt b was amplified. In order to eliminate false positives, amplification products were subjected to a restriction fragment length polymorphism (RFLP) analysis. RESULTS: The human Cyt b gene segment was detected in 86% (49/57) of the females of L. evansi, from 0 to 168 hours after blood ingestion. In 7% (4/57) of the individuals we amplified insect DNA, while in the remaining 7%, the band of interest was not amplified. We did not find any statistical differences between groups of females sacrificed at different times post-blood meal regarding the amplification of the human Cyt b gene segment or the number of samples amplified. CONCLUSION: The human Cyt b gene segment was detectable in L. evansi females up to 168 hours after blood ingestion.

Estimación del tiempo límite de detección del gen citocromo b de humanos en hembras de Lutzomyia evansi / Estimation of time detection limit for human cytochrome b in females of Lutzomyia evansi

Resumen Introducción. Las técnicas de biología molecular han permitido ampliar el conocimiento sobre las fuentes de ingestión de sangre de los insectos vectores. Sin embargo, la utilidad de estas técnicas depende de la cantidad de sangre ingerida y del proceso de digestión en el insecto. Objetivo. Determinar el tiempo límite de detección del gen citocromo b (Cyt b) de humanos en hembras de Lutzomyia evansi alimentadas experimentalmente. Materiales y métodos. Se evaluaron ocho grupos de hembras de L. evansi alimentadas con sangre humana, las cuales fueron sacrificadas en intervalos de 24 horas desde el momento de la ingestión sanguínea. Se extrajo el ADN total de cada hembra y se amplificó un segmento de 358 pb del gen Cyt b. Los productos amplificados fueron sometidos a un análisis de polimorfismos en la longitud de los fragmentos de restricción (Restriction Fragment Length Polymorphism, RFLP), con el fin de descartar falsos positivos. Resultados. El segmento del gen Cyt b de humanos fue detectado en 86 % (49/57) de las hembras de L. evansi a partir de las 0 horas y hasta 168 horas después de la ingestión de sangre. En 7 % (4/57) de los individuos se amplificó el ADN del insecto y en el 7 % restante no se amplificó la banda de interés. No se encontraron diferencias estadísticas en cuanto a la amplificación del segmento del gen Cyt b de humanos ni al número de muestras amplificadas entre los grupos de hembras sacrificadas a distintas horas después de la ingestión. Conclusión. El segmento del gen Cyt b de humanos fue detectable en hembras de L. evansi hasta 168 horas después de la ingestión de sangre.

Abstract Introduction: Molecular biology techniques have allowed a better knowledge of sources of blood meals in vector insects. However, the usefulness of these techniques depends on both the quantity of ingested blood and the digestion process in the insect. Objective: To identify the time limit for detection of the human cytochrome b (Cyt b) gene in experimentally fed females of Lutzomyia evansi. Materials and methods: Eight groups of L. evansi females were fed on human blood and sacrificed at intervals of 24 hours post-ingestion. Total DNA was extracted from each female and a segment of 358 bp of Cyt b was amplified. In order to eliminate false positives, amplification products were subjected to a restriction fragment length polymorphism (RFLP) analysis. Results: The human Cyt b gene segment was detected in 86% (49/57) of the females of L. evansi, from 0 to 168 hours after blood ingestion. In 7% (4/57) of the individuals we amplified insect DNA, while in the remaining 7%, the band of interest was not amplified. We did not find any statistical differences between groups of females sacrificed at different times post-blood meal regarding the amplification of the human Cyt b gene segment or the number of samples amplified. Conclusion: The human Cyt b gene segment was detectable in L. evansi females up to 168 hours after blood ingestion.

The Combination of PlGF Inhibition and MMC as a Novel Anti-Scarring Strategy for Glaucoma Filtration Surgery.

PURPOSE: The complementary effects of mitomycin-C (MMC) and anti-placental growth factor (PlGF) therapy were explored and compared to the combined administration of MMC and aflibercept. Additionally, the effect of PlGF (inhibition) on IOP was investigated, since aqueous PlGF is known to be upregulated in glaucoma patients. METHODS: In the trabeculectomy mouse model, intracameral injection(s) of the PlGF inhibitor (5D11D4) were compared to MMC or aflibercept and to the combination of both compounds. Treatment outcome was studied by bleb investigation and by Sirius Red staining. The effect of subconjunctival PlGF administration and topical 5D11D4 on IOP was investigated in normotensive mice and was compared to topical administration of latanoprost, the gold standard for IOP-lowering. RESULTS: Combination of MMC and 5D11D4 was able to significantly improve surgical outcome compared to monotherapy of MMC or 5D11D4 (n = 20; P < 0.001). Compared to combined treatment of MMC with aflibercept, the simultaneous administration of MMC and 5D11D4 was equally efficacious in improving surgical outcome (n = 15; P = 0.88). In normotensive mice, 5D11D4 was able to significantly reduce the IOP-elevation induced by PlGF (n = 10; P < 0.05), whereas no effect of 5D11D4 was seen in naive mice, which was in contrast to latanoprost. CONCLUSIONS: The current data suggest that application of MMC together with PlGF inhibition may have complementary effects in the improvement of surgical outcome and is equally efficacious as the combined treatment of MMC and aflibercept. Inhibition of PlGF also might open alternative perspectives as IOP-lowering strategy for glaucoma patients with increased aqueous PlGF levels.

Protein Corona Formation on Magnetite Nanoparticles: Effects of Culture Medium Composition, and Its Consequences on Superparamagnetic Nanoparticle Cytotoxicity.

The physicochemical properties and potential cytotoxicity of nanoparticles (NPs) are significantly influenced by their inter- action with proteins, which results in corona formation. Here, we have determined whether corona formation, resulting from interactions between superparamagnetic iron oxide nanoparticles (SPIONs) and different cell culture media, may have consequences for driving NP toxic effects. To address this issue, complementary methods were used. The deter- mination of the hydrodynamic size distribution by ζ (zeta) potential measurement indicated that SPIONs were negatively charged under all conditions but that the actual charge was differed with the cell culture medium used. In vitro protein adsorption studies were carried out using the Bradford protein assay and Fourier transform infrared spectroscopy (FTIR). The Bradford assay revealed that the concentration of unadsorbed proteins and other biomolecules decreased when the SPION concentration increased. FTIR showed that the proteins were, indeed, adsorbed onto the NP surface. This was followed by matrix-assisted laser desorption/ionization time-of-flight secondary ion mass spectrometry (MALDI TOF-SIMS), to identify the adsorbed proteins. Ultimately, three different cell viability assays led to the conclusion that the SPIONs were not toxic for all the concentrations used here. In summary, we found that corona formation on the SPIONs depends on the composition of the culture media but has no consequence for nanotoxicity. We have shown that the application of complementary methods has provided novel insights into SPION/protein interactions.

Pyrazolo[3,4-d]pyrimidines as inhibitor of anti-coagulation and inflammation activities of phospholipase A 2 : insight from molecular docking studies.

Phospholipase A2 (PLA2), isolated from Daboia russelli pulchella (Russell's viper), is enzymatically active as well as induces several pharmacological disorders including neurotoxicity, myotoxicity, cardiotoxicity, anti-coagulant, hemolytic, and platelet effects. Indomethacin reduces the effects of anti-coagulant and pro-inflammatory actions of PLA2. Pyrazolo[3,4-d]pyrimidines constitute a class of naturally occurring fused uracils that posses diverse biological activities. The in-silico docking studies of nine pyrazolo[3,4-d]pyrimidine molecules have been carried out with the X-ray crystal structure of Russell's viper PLA2 (PDB ID: 3H1X) to predict the binding affinity, molecular recognition, and to explicate the binding modes, using AUTODOCK and GLIDE (Standard precision and Extra precision) modules, respectively. Docking results through each method make obvious that pyrazolo[3,4-d]pyrimidine molecules with trimethylene linker can bind with both anti-coagulation and enzymatic regions of PLA2.

Proteomic investigations on the effect of different membrane materials on blood protein adsorption during haemodialysis.

BACKGROUND: During haemodialysis procedure, the contact of blood with the membrane material contained in the hemodialyser results in protein deposition and adsorption, and surface-adsorbed proteins may trigger a variety of biological pathways with potential pathophysiologic consequences. The present work was undertaken to examine for protein adsorption capacity of two membranes used for clinical haemodialysis, namely cellulose triacetate (a derivatized cellulosic membrane) and the synthetic polymer polysulfone-based helixone. MATERIALS AND METHODS: We performed a prospective cross-over study in chronic haemodialysis patients, routinely treated with a cellulose triacetate dialyser (n=3) or with a helixone dialyser (n=3). Dialysers from each patient were obtained after dialysis session, and flushed with a litre of saline to remove residual blood. Adsorbed proteins were then eluted by a strong chaotropic buffer. Patients were next switched to the other membrane dialyser for four weeks, at the end of this period protein adsorption being evaluated again. After silver staining, expression profile protein of the two groups was analyzed by 2-DE gels, analyzed and identified by Peptide Mass-finger printing and MALDI-TOF-MS/MS sequency. Moreover nanoLC-MS/MS shotgun profiling was pursued using a semi-quantitative label free approach by emPAI data analysis. RESULTS: A total of 54 differentially expressed proteins were identified: 22 proteins more concentrated in helixone membrane (predominantly low abundant plasma proteins) and 32 in cellulose triacetate (most represented by high abundant plasma proteins). The difference proved to be related to membrane material and not to patient's characteristics. DISCUSSION: Proteomic techniques represent a useful approach for the investigation of proteins surface-adsorbed onto a haemodialysis membrane, and can also be applied for critical assessment to compare efficiencies of different dialyser membrane materials in the adsorption of plasma proteins.

Poly(N-vinylpyrrolidone)-modified poly(dimethylsiloxane) elastomers as anti-biofouling materials.

A new method for the modification of poly(dimethylsiloxane) (PDMS) elastomer surfaces with hydrophilic poly(N-vinylpyrrolidone) (PVP) has been developed. PVP chains were grafted from the PDMS surface by surface-initiated atom transfer radical polymerization (SI-ATRP). The resulting surfaces were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), atomic force microscopy (AFM) and water contact angle measurements. It was shown that the modified surfaces were strongly hydrophilic, indicating that the PVP grafts dominate the surface and define its properties. The anti-fouling properties of the grafted surfaces were demonstrated in protein adsorption and cell adhesion experiments. Both protein adsorption and cell adhesion were inhibited significantly on the PVP-modified PDMS surfaces compared to unmodified controls. It is concluded that modification by SI-ATRP grafting of PVP is an effective method for the preparation of anti-biofouling PDMS materials.

Gold-peptide nanoconjugate cellular uptake is modulated by serum proteins.

Gold nanoparticles (Au NPs, 20 nm) were conjugated with two different cysteine-terminated peptides. Radio-ligand binding studies were conducted to characterize Au NP-peptide binding, suggesting both covalent and noncovalent interactions. The interactions of serum proteins with Au NP-peptide nanoconjugates were determined using gel electrophoresis and dynamic light scattering. Serum proteins rapidly bound the nanoconjugates (15 minutes). The cellular uptake of free peptides and nanoconjugates into mouse myogenic (Sol8) cells was investigated in the absence or presence of serum. In the absence of serum, peptides presented as nanoconjugates showed significantly higher intracellular fluorescence signals compared to those in the presence of serum (P < 0.05), suggesting that serum proteins inhibit Au NP-mediated peptide delivery. The cellular uptake of nanoconjugates was also confirmed using transmission electron microscopy. These data suggest that Au NP-peptide nanoconjugates are a useful platform for intracellular delivery of therapeutics. However, a deeper understanding of the mechanisms regulating their uptake and intracellular trafficking is needed.

The influence of clonidine co-administration on the extent of lidocaine protein binding to rat serum and tissues.

Lidocaine is an amide local anesthetic and clonidine is an antihypertensive (α2-adrenergic agonist). The use of these two drugs in combination is recommended to enhance the analgesic effect of lidocaine. The aim of this study was to investigate the influence of clonidine co-administration on the extent of lidocaine binding to rat serum, heart and maxillofacial tissues in vivo and in vitro. Thirty-two Wistar rats received either lidocaine alone, or lidocaine and clonidine, in the masseter muscle, and were then sacrificed 15 or 30 min after treatment. Serum, masseter, mandible and heart samples were then isolated and incubated in 0.9% NaCl solution for 12 h at 8°C. The extent of binding in the incubation medium and the serum was estimated by ultrafiltration, and the free lidocaine fraction was determined by the radioscopic method in a ß-counter. An in vitro procedure was also performed. Serum, heart, masseter and mandible samples were incubated at 37°C for 15 or 30 min in Ringer's solution containing either lidocaine or lidocaine and clonidine, and the samples were similarly subjected to ultrafiltration. The percentage binding of lidocaine was again estimated by the radioscopic method. Lidocaine levels were found to be increased by clonidine co-administration in vivo and the free lidocaine fraction was enhanced in vitro as well in the examined tissues, obviously through mechanisms related to protein binding alterations.

Effect of surface microstructure and wettability on plasma protein adsorption to ZnO thin films prepared at different RF powers.

In this paper, the adsorption behavior of plasma proteins on the surface of ZnO thin films prepared by radio frequency (RF) sputtering under different sputtering powers was studied. The microstructures and surface properties of the ZnO thin films were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible optical absorption spectroscopy and contact angle techniques. The results show that the ZnO thin films have better orientation of the (0 0 2) peak with increasing RF power, especially at around 160 W, and the optical band gap of the ZnO films varies from 3.2 to 3.4 eV. The contact angle test carried out by the sessile drop technique denoted a hydrophobic surface of the ZnO films, and the surface energy and adhesive work of the ZnO thin films decreased with increasing sputtering power. The amounts of human fibrinogen (HFG) and human serum albumin (HSA) adsorbing on the ZnO films and reference samples were determined by using enzyme-linked immunosorbent assay (ELISA). The results show that fewer plasma proteins and a smaller HFG/HSA ratio adsorb on the ZnO thin films' surface.

El proceso farmacocinético: ¿llega el fármaco al sitio de acción?. Distribución de fármacos en el organismo (LADME) / The pharmacokinetic process: is the drug getting to its site of action?: drug distribution (ADME)

La mayoría de los fármacos son transportados en la sangre unidos a proteínas plasmáticas tales como la albúmina (ácidos débiles), globulinas (hormonas), lipoproteínas (bases débiles) y la ?-glucoproteína (bases débiles). Solamente la fracción libre del fármaco, no la que se encuentra unida a las proteínas del plasma, puede actuar en los receptores celulares, atravesar las membranas de las células en los tejidos, acceder a las enzimas y, de esta forma, distribuirse por todo el organismo además de experimentar procesos metabólicos y de excreción (principalmente renal). Las modificaciones acontecidas en la unión del fármaco a las proteínas plasmáticas pueden ocasionar cambios en la distribución farmacológica. Dichas modificaciones pueden tener relevancia clínica cuando el fármaco se encuentra unido a las proteínas plasmáticas en una proporción superior al 90% de la cantidad total de fármaco presente en el plasma y alcanza un intervalo terapéutico reducido. Además, se precisa que tenga un volumen de distribución pequeño (inferior a 0,15 L/kg), ya que si se encuentra ampliamente distribuido en los tejidos, incrementos (incluso importantes) en la fracción de fármaco libre, pueden carecer de significación clínica(AU)

Many drugs are bound to circulating proteins, usually albumin (acidic drugs), but also globulins (hormones), lipoproteins (basic drugs), and acid glycoproteins (basic drugs). Only the fraction of drug that is not protein-bound can bind to cellular receptors, pass across tissue membranes, and gain access to cellular enzymes, thus being distributed to body tissues, metabolized, and excreted (for example by the kidney). Changes in protein binding can therefore sometimes cause changes in drug distribution. For such changes to be important, the bound drug must constitute more than 90% of the total drug in the plasma and possess a reduced therapeutic window. Besides this, the extent of distribution of the drug to the tissues must be small (less than 0.15 L/kg). This is because if the drug is widely distributed to the body tissues, then even large increases in the amount of unbound drug in the plasma will be unimportant(AU)

Prolonged effect of GlycoPEGylated rFVIIa (40k-PEG-rFVIIa) in rabbits correlates to activity in plasma.

The pharmacokinetics and pharmacodynamics of 40k-PEG-rFVIIa, a GlycoPEGylated derivative of recombinant wild-type FVIIa, were compared with rFVIIa in rabbits. The procoagulant effect was determined as the weight of the clot formed in a defined segment of a facial vein. A time course study was conducted where ligation was made 10 minutes, 12 or 24 hours after i.v. injection of equimolar doses of 40k-PEG-FVIIa or rFVIIa (2 mg/kg). This dose was selected based on a dose response study and a duration of effect study with rFVIIa. The clot weight increased with increasing doses of rFVIIa, and the duration of effect correlated with the plasma FVIIa clot activity. The plasma half-life of 40k-PEG-rFVIIa measured as FVIIa clot activity was found to be 25 hours, which was 5-6 times longer than rFVIIa. The aPTT and PT were reduced, and the measured increase in thrombin-antithrombin correlated to the effect on clot formation. Thus, the effect was similar at ligation 10 minutes after administration of 40k-PEG-rFVIIa or rFVIIa. At 12 hours, the effect of rFVIIa was absent while significant effect was seen 12 and 24 hours post dosing with 40k-PEG-rFVIIa. No consumption of platelets or fibrinogen was found and no thrombi formation was seen in histological examination of various organs. In conclusion, 40k-PEG-rFVIIa has shown prolonged duration of effect that correlated to various plasma markers and FVIIa clot activity. In perspective, the data support further clinical development of 40k-PEG-rFVIIa to potentially become a long-acting recombinant treatment option for prophylaxis in haemophilia patients with inhibitors.

Preparation and properties of branched oligoglycerol modifiers for stabilization of liposomes.

We examined the effect on drug delivery of liposomes with surfaces that were modified with branched oligoglycerols (BGLs) and explored possible formulation advantages to increase drug exposure. BGL012 is a branched oligoglycerol derivative with a cascade-like structure of 12 glycerol units, characterized as a widely spread structure in aqueous solution. We prepared BGL-phospholipid derivatives (BGL-PEs), including BGL012, by coupling 1,2-distearoylphosphatidylethanolamine to BGLs. BGL012-PE modification of the liposomes (BGL012L) achieved a long circulation time after intravenous injection in rats. The circulation lifetime of BGL012L was almost the same as that of polyethylene glycol (PEG)-modified liposomes. The surface of BGL012L induced the formation of a fixed aqueous layer and reduced protein adsorption on the liposome surface, without strong interference with the binding reaction on the liposome. Thus, the newly synthesized branched oligoglycerol derivatives are considered to have useful hydrophilic and physical properties for modifying the liposome surface to increase drug exposure.