PEGylated Liposomes Research Articles

Novel Synergistic Approach for Bioactive Macromolecules: Evaluating the Efficacy of Goat Placenta Extract in PEGylated Liposomes and Microspicules for Chemotherapy-Induced Hair Loss.

Chemotherapy-induced hair loss is a distressing side effect of cancer treatment, and medical interventions are often needed to address this problem. The objectives of this study were to evaluate the bioactivity of goat placenta (GP) extract on both normal and chemotherapy-induced hair cells and to develop PEGylated liposomes (PL) and microspicule (MS) formulations for promoting hair growth in patients with chemotherapy-induced hair loss. The bioactivities of GP extract on human follicle dermal papilla (HFDP) cells and cells damaged by chemotherapy were assessed. GP extract was incorporated into PLs and MS gel (PL-MS) and then investigated in vitro skin permeation and in vivo studies on the scalps of patients with chemotherapy-induced hair loss. GP extract stimulated HFDP cell proliferation in both normal and cisplatin-damaged cells. PL nanovesicles and MS gel worked synergistically to deliver macromolecular proteins into the skin and hair follicles. The application of GP extract-loaded PL-MS to the scalps of chemotherapy-treated patients for 12 weeks significantly enhanced the hair growth rate, without causing skin irritation. In conclusion, GP extract promoted the proliferation of hair cells damaged by chemotherapy, when this extract, combined with PL-MS, effectively delivered bioactive macromolecules across the skin and hair follicles, resulting in successful regrowth of hair post-chemotherapy.

Exploring the Antitumor Efficacy of PEGylated Liposomes Loaded with Licorice Extract for Cancer Therapy.

Glycyrrhizic Acid (GA), a compound derived from licorice, has exhibited promising anticancer properties against several cancer types, including Prostate Cancer (PCa) and Gastric Cancer (GCa). This study has introduced a novel approach involving the encapsulation of GA and Licorice extract (Lic) into Polyethylene Glycol Liposomes (PEG-Lip) and assessed their efficacy against AGS (human gastric cancer) and PC-3 (human prostate cancer) cells, marking the first report of this endeavor. We synthesized GA-loaded PEG-Lip (GA PEG-Lip) and Lic-loaded PEG-Lip (Lic PEG-Lip) through the reverse-phase evaporation method. Characterization of these liposomal formulations revealed their size, drug encapsulation, and loading efficiencies to be 110 ± 2.05 nm, 117 ± 1.24 nm; 61 ± 0.81%, 34 ± 0.47%; and 8 ± 0.41% and 4.6 ± 0.21%, respectively. Importantly, the process has retained the chemical structure of both GA and Lic. Furthermore, GA and Lic have been released from the PEG-Lip formulations in a controlled manner. In our experiments, both nanoformulations exhibited enhanced cytotoxic effects against AGS and PC-3 cells. Notably, GA PEG-Lip outperformed Lic PEG-Lip, reducing the viability of PC-3 and AGS cells by 12.5% and 15.9%, respectively. These results have been corroborated by apoptosis assays, which have demonstrated GA PEG-Lip and Lic PEG-Lip to induce stronger apoptotic effects compared to free GA and Lic on both PC-3 and AGS cells. This study has underscored the potential of encapsulating GA and Lic in PEG-Lip as a promising strategy to augment their anticancer efficacy against prostate and gastric cancers.

PEGylated nanoparticles interact with macrophages independently of immune response factors and trigger a non-phagocytic, low-inflammatory response

Poly-ethylene-glycol (PEG)-based nanoparticles (NPs) - including cylindrical micelles (CNPs), spherical micelles (SNPs), and PEGylated liposomes (PLs) - are hypothesized to be cleared in vivo by opsonization followed by liver macrophage phagocytosis. This hypothesis has been used to explain the rapid and significant localization of NPs to the liver after administration into the mammalian vasculature. Here, we show that the opsonization-phagocytosis nexus is not the major factor driving PEG-NP – macrophage interactions. First, mouse and human blood proteins had insignificant affinity for PEG-NPs. Second, PEG-NPs bound macrophages in the absence of serum proteins. Third, lipoproteins blocked PEG-NP binding to macrophages. Because of these findings, we tested the postulate that PEG-NPs bind (apo)lipoprotein receptors. Indeed, PEG-NPs triggered an in vitro macrophage transcription program that was similar to that triggered by lipoproteins and different from that triggered by lipopolysaccharide (LPS) and group A Streptococcus. Unlike LPS and pathogens, PLs did not increase transcripts involved in phagocytosis or inflammation. High-density lipoprotein (HDL) and SNPs triggered remarkably similar mouse bone-marrow-derived macrophage transcription programs. Unlike opsonized pathogens, CNPs, SNPs, and PLs lowered macrophage autophagosome levels and either reduced or did not increase the secretion of key macrophage pro-inflammatory cytokines and chemokines. Thus, the sequential opsonization and phagocytosis process is likely a minor aspect of PEG-NP – macrophage interactions. Instead, PEG-NP interactions with (apo)lipoprotein and scavenger receptors appear to be a strong driving force for PEG-NP – macrophage binding, entry, and downstream effects. We hypothesize that the high presence of these receptors on liver macrophages and on liver sinusoidal endothelial cells is the reason PEG-NPs localize rapidly and strongly to the liver.

Activation of CYP3A by ABC phenomenon potentiates the hepatocellular carcinoma-targeting therapeutic effects of PEGylated anticancer prodrug liposomes.

Reduced enzyme activity in hepatocellular carcinoma (HCC) and poor targeting limit the application of enzyme-activating prodrugs, which is also detrimental to the effective treatment of HCC. Here, we investigated whether accelerated blood clearance (ABC) phenomenon occurs in HCC models following repeated injections of PEGylated liposomes (PEG-L), thus inducing prodrugs accumulation and activation in the liver and exerting highly effective and low-toxicity therapeutic effects on HCC. Firstly, PEGylated liposomal cyclophosphamide (PEG-CP-L) was prepared by solvent injection and characterized. Importantly, pre-injection of PEG-L induced ABC phenomenon and activation of CYP3A in both HCC rats and HCC mice by investigating the effects of repeated injections of PEG-L on pharmacokinetics and tissue distribution. Next, the efficacy and toxicity of repeated injections of PEG-L in HCC mice were examined, and our data indicate that repeated injections are administered in a manner that significantly enhances the antitumor effect compared to controls with little or no toxicity to other organs. To further reveal the pharmacokinetic mechanism of PEG-L repeated administration for the treatment of HCC, the protein expression of hepatic CYP3A and the concentration of CP in the liver and spleen of HCC mice by inhibiting CYP3A were analyzed. These results revealed that inducing CYP3A to accelerate the rapid conversion of prodrugs that accumulate significantly in the liver is a key mechanism for the treatment of HCC with repeated injections of PEG-L. Collectively, this work taps into the application potential of the ABC phenomenon and provides new insights into the clinical application of PEGylated nanoformulations. Significance Statement This study revealed that repeated injections of PEG-L could induce the ABC phenomenon characterized by hepatic accumulation and CYP3A activation based on HCC rats and HCC mice. Furthermore, it was verified that induction of the ABC phenomenon dependent on hepatic accumulation and CYP3A activation could enhance the anti-hepatocellular carcinoma effects of PEGylated anticancer prodrugs in HCC mice. This elucidated the relevant pharmacokinetic mechanisms and unearths new clues for solving the clinical application of PEGylated nanoparticles.

LPS adsorption and inflammation alleviation by polymyxin B-modified liposomes for atherosclerosis treatment.

Chronic inflammation is critical in the onset and progression of atherosclerosis (AS). The lipopolysaccharide (LPS) level in the circulation system is elevated in AS patients and animal models, which is correlated with the severity of AS. Inspired by the underlying mechanism that LPS could drive the polarization of macrophages toward the M1 phenotype, aggravate inflammation, and ultimately contribute to the exacerbation of AS, LPS in the circulation system was supposed to be the therapeutic target for AS treatment. In the present study, polymyxin (PMB) covalently conjugated to PEGylated liposomes (PLPs) were formulated to adsorb LPS through specific interactions between PMB and LPS. Invitro, the experiments demonstrated that PLPs could adsorb LPS, reduce the polarization of macrophages to M1 phenotype and inhibit the formation of foam cells. Invivo, the study revealed that PLPs treatment reduced the serum levels of LPS and pro-inflammatory cytokines, decreased the proportion of M1-type macrophages in AS plaque, stabilized AS plaque, and downsized the plaque burdens in arteries, which eventually attenuated the progression of AS. Our study highlighted LPS in the circulation system as the therapeutic target for AS and provided an alternative strategy for AS treatment.

Anti-PEG IgM production induced by PEGylated liposomes as a function of administration route.

Modifying the surface of nanoparticles with polyethylene glycol (PEG) is a commonly used approach for improving the in vitro stability of nanoparticles such as liposomes and increasing their circulation half-lives. We have demonstrated that, in certain conditions, an intravenous (i.v.) injection of PEGylated liposomes (PEG-Lip) induced anti-PEG IgM antibodies, which led to rapid clearance of second doses in mice. SARS-CoV-2 vaccines, composed of mRNA-containing PEGylated lipid nanoparticles, have been widely administered as intramuscular (i.m.) injections, so it is important to determine if PEGylated formulations can induce anti-PEG antibodies. If the favorable properties that PEGylation imparts to therapeutic nanoparticles are to be widely applicable this should apply to various routes of administration. However, there are few reports on the effect of different administration routes on the in vivo production of anti-PEG IgM. In this study, we investigated anti-PEG IgM production in mice following i.m., intraperitoneal (i.p.) and subcutaneous (s.c.) administration of PEG-Lip. PEG-Lip appeared to induce anti-PEG IgM by all the tested routes of administration, although the lipid dose causing maximum responses varied. Splenectomy attenuated the anti-PEG IgM production for all routes of administration, suggesting that splenic immune cells may have contributed to anti-PEG IgM production. Interestingly, in vitro experiments indicated that not only splenic cells but also cells in the peritoneal cavity induced anti-PEG IgM following incubation with PEG-Lip. These observations confirm previous experiments that have shown that measurable amounts of PEG-Lip administered i.p., i.m. or s.c. are absorbed to some extent into the blood circulation, where they can be distributed to the spleen and/or peritoneal cavity, and are recognized by B cells, triggering anti-PEG IgM production. The results obtained in this study have important implications for developing efficient PEGylated nanoparticular delivery system.

Obesity and inflammation influence pharmacokinetic profiles of PEG-based nanoparticles.

Most patients that will be treated with soft nanoparticles (NPs) will be obese. Yet, NP testing, which begins with pharmacokinetic (PK) and toxicity studies, is carried out almost exclusively in lean rodents having healthy livers and low inflammation. To address this knowledge gap, we determined the PK and toxicity of tail-vein-injected, PEG-based cylindrical nanoparticles (CNPs) and PEGylated liposomes (PLs) as a function of obesity, liver health, and inflammation in leptin-deficient ob/ob and wild-type C57BL/6J mice. CNPs localized faster to obese livers than to healthy livers within 24h of injection. PLs localized faster to obese livers than to healthy livers but only 30min post-injection. Afterwards PL localization to lean livers was higher than localization to obese livers. Overall, PL liver signal peaked ∼6h post-injection in lean mice, ∼24h post-injection in heavy mice, and∼48h post-injection in obese mice. CNPs and PLs were non-toxic to mouse livers as assessed by histology; they reduced many cytokine and chemokine levels that were elevated by obesity. Liver macrophage depletion reduced CNP and PL liver localization as expected; liver sinusoidal endothelial cell (LSEC) depletion reduced PL liver localization but surprisingly increased CNP liver localization. The intensity of RAW264.7 macrophages was higher after CNP incubations than with PL incubations; conversely, the intensity of LSECs was higher after PL incubations than with CNP incubations. This shows the potential for key differences in NP-liver interactions. Triggering inflammation by administering lipopolysaccharide (LPS) to mice increased CNP liver localization but decreased PL liver localization. The results show that obesity and inflammation in a mouse model and in vitro affect soft PEG-based NP interaction with macrophages and LSECs, but also that these NPs can reduce pro-inflammatory pathways increased by obesity.

The Use of a Pegylated Liposome in a Phase II Trial to Enhance the Potency and Extend the Dosing Interval of Prophylactic Standard Half-Life FVIII, without Increasing the Dose

Background: Prophylactic recombinant FVIII replacement therapy currently relies on the frequent intravenous (IV) administration (once every other day/2-3 times weekly) of Standard Half-Life (SHL) FVIII at a dose 20-40 IU/kg. The evolution of Extended Half-Life (EHL) FVIII has extended the dosing interval to every 4 days or 2-3 times weekly although this also relies on administering higher doses (30-60 IU/kg). Co-formulation of a standard dose (35IU/kg) of SHL FVIII with Pegylated liposomes (PEGLip) can enhance the coagulation performance of FVIII by enhancing clotting activity and its duration of efficacy, ultimately enabling an extended dosing interval. Such benefits may also be conferred if instead of co-formulating prior to injection, the PEGLip is administered after FVIII has been injected. We have developed PEGLip ("XLR8") as the first independent adjuvant product to increase the efficacy of any SHL rFVIII, increasing their dosing intervals and providing haemostatic cover with a lower dose then is possible with current EHL rFVIII replacement products. The XLR8 adjuvant approach used with SHL factors may provide a safe, cost-effective way to reduce injection burden(potentially improving compliance) and the amount of (expensive) FVIII consumed Aims: To demonstrate (a) that PEGLip administered intravenously (IV) to severe haemophilia A (HA) patients that have received a prophylactic dose of rFVIII immediately beforehand prolongs haemostatic cover and (b) to establish a greater dosing interval. Methods: Stage A: Fourteen severe haemophilia A patients were given single IV injections of FVIII (simoctocog alfa) at a dose 35 IU/kg, which were followed after 15 minutes by single infusions of PEGLip 22mg/kg PEGLip and assessed for clotting activity at 0 hours (pre-injection) and at 20min, 1, 2, 4, 8, 24 hours, and daily thereafter up to 7 days using Rotational Thromboelastometry. Stage B: Patients received IV injections of FVIII followed by an injection of PEGLip for 6-weeks at a frequency determined by the investigator based on results obtained during Stage A. Results: These are shown in the table below. Treatment with PEGLip-FVIII was highly tolerated with no inhibitor generation. No adverse drug reactions were reported. The mean frequency of administration of PEGLip-FVIII was every 4.9±1.4 days. The mean number of bleeding episodes reported during Stage B was significantly reduced by 84% to 0.18±0.37 per month compared with 1.10±0.64 per month recorded during the 24 weeks prior to enrollment. Conclusion: The separate injection of PEGLip following a standard-of-care prophylactic injection of FVIII in severe HA patients demonstrated efficacy in preventing spontaneous bleeds with an extended dosing interval of 4.9 days. Over the course of a year this could reduce the injection burden of every-other-day SHL administration by 50%, i.e. 91 injections vs. 182 injections, potentially improving patient compliance and convenience. Compared to a once-every-4-day injection of 45 IU/kg, using 35 IU/kg per administration would reduce consumption of rFVIII by 22%, This trial has looked at the enhancement of a 4th SHL generation, B-domain deleted FVIII. Further work is required to establish if different forms of SHL can also benefit from this enhancement and also whether it can help current EHL products to maintain homeostasis at even longer dosing intervals and lower doses. Acknowledgements: The Authors acknowledge the co-operation of the following clinicians in undertaking the study: Margarita Timofeeva1, Tatiana Pospelova2, Marina Kosinova3, Igor Kurtov4,Alexandr Myasnikov5, 1Scientific Research Institute of Hematology and Blood Transfusion, Kirov, Russian Federation, 2State Medical University, City Hematology Centre, Novosibirsk, Russian Federation, 3District Clinical Hospital, Kemerovo, Russian Federation, 4State Medical University, Samara, Russian Federation, 5Republican Hospital n.a. V.A. Baranov, Petrozavodsk, Russian Federation. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Prophylactic Treatment of Severe Haemophilia a Patients with Inhibitors to FVIII with Peglip-FVIII

Background: FVIII replacement therapy is ineffective for severe haemophilia A (HA) patients who develop inhibitors to FVIII. Patients with intractable inhibitors currently require FVIII mimetics and/or bypassing agents to prevent bleeding. A previously presented interim analysis[1] demonstrated that severe haemophilia A patients with a clinical history of developing inhibitors to FVIII could be prophylactically treated with recombinant FVIII co-injected with PEGylated liposomes (PEGLip), termed PEGLip-FVIII and may present an option for the prophylactic treatment of inhibitor patients. Aims: To establish safety and efficacy of PEGLip-FVIII and demonstrate (a) that PEGLip-FVIII administered intravenously (IV) to severe HA patients with history of inhibitors to FVIII enhances their clotting activity and (b) that PEGLip-FVIII administered to severe HA patients with active inhibitors to FVIII enhances their clotting activity. Methods: Stage A: Thirteen patients that were clinically defined as inhibitor patients were given single IV injections of PEGLip-FVIII (simoctocog alfa) at a dose of 22mg/kg PEGLip + 35 IU/kg FVIII and assessed for clotting activity at 0 hours (pre-injection) and at 20min, 1, 2, 4, 8, 24 hours, and daily thereafter up to 7 days using Rotational Thromboelastometry. Stage B: Patients received IV injections of PEGLip-FVIII for 6-weeks at a frequency determined by the investigator based on results obtained during Stage A. Eight of the patients had a history of developing inhibitors to FVIII but did not have active inhibitors at screening; the remaining five patients had active low-titre inhibitors at screening. Inhibitor titres were monitored throughout. Results: Results are shown in the table. Conclusion: Treatment with PEGLip-FVIII was well tolerated with no clinically significant changes in inhibitor titres in inhibitor patients in both groups. No adverse drug reactions were reported. The mean frequency of administration of PEGLip-FVIII was every 5.5±1.3 days. The mean number of bleeding episodes reported during Stage B was significantly reduced by 74% to 0.3±0.6 per month compared with 1.0±0.4 per month recorded during the 24 weeks prior to enrollment. Conclusion: PEGLip-FVIII in inhibitor patients demonstrated efficacy in preventing spontaneous bleeds without increasing inhibitor titres, indicating a novel FVIII-based treatment for this cohort. The dosing interval of 5.5days at 35IU/kg represents a significant reduction in FVIII infusion frequency. Acknowledgements: The Authors acknowledge the co-operation of the following clinicians in undertaking the study: Nadezhda Zozulia1, Margarita Timofeeva2, Tatiana Pospelov32, Marina Kosinova4, Igor Kurtov5,Heghine Khachatryan6. 1National Medical Research Centre of Hematology, Moscow.2Scientific Research Institute of Hematology and Blood Transfusion, Kirov, Russian Federation, 3State Medical University, City Hematology Centre, Novosibirsk, Russian Federation, 4District Clinical Hospital, Kemerovo, Russian Federation, 5State Medical University, Samara, Russian Federation, 6Haematology Center after professor R. Yeolyan, Yerevan, Armenia. [1] Timofeeva M et al. Prophylactic treatment of severe haemophilia A patients with inhibitors to FVIII with PEGLip-FVIII. Blood 2021; 138 (Suppl 1): 1040 (abstract) Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

PASylation improves pharmacokinetic of liposomes and attenuates anti-PEG IgM production: An alternative to PEGylation

PASylation, which was recently reported as the conjugation of pharmacologically active compounds with polypeptide sequences mainly made of proline, alanine and serine, has been proposed as an alternative to PEGylation. In this study, we designed PAS-modified liposomes (PASylated liposomes) and studied the effect of the incorporation of PAS-lipid on the stability and pharmacokinetic properties of liposomes, and compared them both in vitro and in vivo to PEGylated liposomes. Results showed that PASylated liposomes modified with single-chained PAS-lipid C16-(PA3)7 (SC-PAS-Lip) showed comparable storage and serum stability to PEGylated liposomes (PEG-Lip), and a significantly decreased macrophage uptake compared with unmodified liposomes. SC-PAS-Lip displayed long circulating pharmacokinetic profile which was not impacted by the repeated administration of liposomes, and they were less likely to induce the production of anti-PEG IgM compared with PEGylated liposomes, presenting PASylation as an alternative liposome modification strategy to PEGylation.

A Maleimide-Terminally Modified PEGylated Liposome Induced the Accelerated Blood Clearance Independent of the Production of Anti-PEG IgM Antibodies.

PEGylated liposomes (PL) lose their long-circulating characteristic when administered repeatedly, called the accelerated blood clearance (ABC) phenomenon. The ABC phenomenon is generally thought to occur when the anti-polyethylene glycol (PEG) antibody (anti-PEG immunoglobulin M (IgM)) expressed in the spleen B cells triggered by the first dose of PL binds to the second and subsequent doses of PL, leading to activation of the complement system. MAL-PEG-DSPE, a PEG lipid with a maleimide (MAL) group at the PEG terminal, is used in various studies as a linker for ligand-bound liposomes such as antibody-modified liposomes. However, most ABC phenomenon research used PL with a terminal methoxy group (PL-OCH3). In this study, we prepared MAL-PEG-DSPE liposomes (PL-MAL) to evaluate the effect of PL-MAL on the ABC phenomenon induction compared to PL-OCH3. Pharmacokinetic, anti-PEG IgM secretion and complement activation analyses of these liposomes were conducted in mice. Interestingly, despite C3 bound to the surface of the initially administered PL-MAL, the administered PL-MAL showed high blood retention, demonstrating the same results as PL-OCH3. On the other hand, although the secretion of anti-PEG IgM induced by PL-MAL was lower than PL-OCH3, the second dose of PL-MAL rapidly disappeared from the blood. These results suggest that the antibody produced from the first dose of PL-MAL binds to the second dose of PL-MAL, thereby activating C3 to act as an opsonin which promotes phagocytic uptake. In conclusion, PL-MAL induced the ABC phenomenon independent of the production of IgM antibodies against PEG. This study provides valuable findings for further studies using ligand-bound liposomes.

The role of glutathione conjugation on the transcellular transport process of PEGylated liposomes across the blood brain barrier

Notwithstanding the growing evidence of improved drug delivery efficiency to the brain by ligand modification of PEGylated liposomes, the comprehensive knowledge of their transport processes and payload across the BBB is yet to be revealed. Herein, this study sought to understand the glutathione (GSH) ligand effect on transcellular transport mechanisms of liposomes through the blood–brain barrier (BBB) by comparing PEGylated liposomes (PEG-L) and GSH PEGylated liposomes (GSH-PEG-L). Endocytosis and exocytosis of liposomes including the role of secreted extracellular vesicles (EVs) of brain endothelial cells (BECs) were assessed. Furthermore, pharmacokinetics and brain distribution analysis of gemcitabine loaded liposomes were carried out in healthy rats to ascertain the in vivo applicability. Our findings suggested that the presence of GSH increased the cellular uptake of liposomes by up to 3-fold in human brain microvascular endothelial cells depending on the dose but not in astrocytes. The cell exposure to liposomes particularly GSH-PEG-L dramatically increased the cell secretion of small and microvesicles with liposomal components, though different liposomes preferred different vesicles for exocytosis. This correlated with GSH-PEG-L transport efficiency of 4 % across the in vitro BBB model in 24 h, 1.7-fold higher than that of PEG-L (p < 0.05). In rats, while PEG-L and GSH-PEG-L showed similar pharmacokinetic profiles and prolonged circulation properties, 3.8 % of the total injected dose (ID) of gemcitabine was found in the brain of the GSH-PEG-L group at 8 h post-injection, compared with 2.8 % ID in the PEG-L group. A brain: blood concentration ratio of 1.27 ± 0.12 indicated that an active transport mechanism to cross the BBB for GSH-PEG-L. Overall, this study revealed that GSH augmented the transcellular transport efficiency of liposomes through BBB to improve targeted brain delivery by enhancing cellular uptake and vesicular exocytosis route of BECs.

Improving cellular uptake and bioavailability of periplocymarin-linoleic acid prodrug by combining PEGylated liposome

Periplocymarin (PPM), a cardiac glycoside isolated from Cortex periplocae, has a strong anti-tumor effect against various cancer cells. However, cardiotoxicity and rapid metabolism hinder its clinical applications. In this study, small molecule prodrug was integrated into PEGylated liposome to improve the efficiency of periplocymarin in vivo. The periplocymarin-linoleic acid (PL) prodrug was constructed by conjugating the linoleic acid with PPM via esterification, which was further facilitated to form PEGylated liposome (PL-Lip) through film dispersion. Compared with PL self-assembling nano-prodrug (PL-SNP), PL-Lip showed better colloid stability, sustained drug release kinetics, and enhanced cellular uptake by tumor cells. Notably, PL-Lip performed better than PPM and PL-SNP in terms of tumor distribution and pharmacokinetics, which include bioavailability and half-life. Altogether, the prodrug PEGylated liposome represents a good strategy and method for long-circulating and tumor-targeting delivery of periplocymarin with enhanced clinical application prospect.

Estrone-Conjugated PEGylated Liposome Co-Loaded Paclitaxel and Carboplatin Improve Anti-Tumor Efficacy in Ovarian Cancer and Reduce Acute Toxicity of Chemo-Drugs.

PurposeOvarian cancer is the most lethal gynecologic malignancy. The combination of paclitaxel (PTX) and carboplatin (CBP) is the first-line remedy for clinical ovarian cancer. However, due to the limitations of adverse reaction and lacking of targeting ability, the chemotherapy of ovarian cancer is still poorly effective. Here, a novel estrone (ES)-conjugated PEGylated liposome co-loaded PTX and CBP (ES-PEG-Lip-PTX/CBP) was designed for overcoming the above disadvantages.MethodsES-PEG-Lip-PTX/CBP was prepared by film hydration method and could recognize estrogen receptor (ER) over-expressing on the surface of SKOV-3 cells. The characterizations, stability and in vitro release of ES-PEG-Lip-PTX/CBP were studied. In vitro cellular uptake and its mechanism were observed by fluorescence microscope. In vivo targeting effect in tumor-bearing mice was determined. Pharmacokinetics and biodistribution were studied in ICR mice. In vitro cytotoxicity and in vivo anti-tumor efficacy were evaluated on SKOV-3 cells and tumor-bearing mice, respectively. Finally, the acute toxicity in ICR mice was explored for assessing the preliminary safety of ES-PEG-Lip-PTX/CBP.ResultsOur results showed that ES-PEG-Lip-PTX/CBP was spherical shape without aggregation. ES-PEG-Lip-PTX/CBP exhibited the optimum targeting effect on uptake in vitro and in vivo. The pharmacokinetics demonstrated ES-PEG-Lip-PTX/CBP had improved the pharmacokinetic behavior. In vitro cytotoxicity showed that ES-PEG-Lip-PTX/CBP maximally inhibited SKOV-3 cell proliferation and its IC50 values was 1.6 times lower than that of non-ES conjugated liposomes at 72 h. The in vivo anti-tumor efficacy study demonstrated that ES-PEG-Lip-PTX/CBP could lead strong SKOV-3 tumor growth suppression with a tumor volume inhibitory rate of 81.8%. Meanwhile, acute toxicity studies confirmed that ES-PEG-Lip-PTX/CBP significantly reduced the toxicity of the chemo drugs.ConclusionES-PEG-Lip-PTX/CBP was successfully prepared with an optimal physicochemical and ER targeting property. The data of pharmacokinetics, anti-tumor efficacy and safety study indicated that ES-PEG-Lip-PTX/CBP could become a promising therapeutic formulation for human ovarian cancer in the future clinic.

PEG-grafted liposomes for enhanced antibacterial and antibiotic activities: An in vivo study

Staphylococcus aureus (S. aureus) biofilm-associated infections are a primary concern for public health worldwide. Current therapeutics cannot penetrate the biofilms efficiently, resulting in low drug concentrations at the infected sites and increasing the frequency of drug usage. To solve this issue, nanotechnology platforms seem to be a promising approach. In this study, the potential therapeutic effects of (PEG)ylated liposome (PEG-Lip) for the delivery of nafcillin (NF) antibiotic were assessed. The results demonstrated that NF-loaded liposome (Lip-NF) and NF-loaded PEG-Lip (PEG-Lip-NF) released 76.4 and 62% of the loaded NF, respectively, in a controlled manner after 50 h. Also, it was found that PEG-Lip-NF, compared to Lip-NF and NF, was more effective against a methicillin-susceptible S. aureus (MSSA; minimum inhibitory concentration (MIC): 1.0 ± 0.03, 0.5 ± 0.02, and 0.25 ± 0.01 μg/mL; and minimum biofilm inhibitory concentration (MBIC50): 4.0 ± 0.18, 1.0 ± 0.04, and 0.5 ± 0.02 μg/mL for NF, Lip-NF, and PEG-Lip-NF, respectively). PEG-Lip-NF, compared to NF and Lip-NF, could also more efficiently decrease the side effects of NF through improving human MG-63 osteoblast cell viability (cell viability at 100 μM of NF: 76, 68, and 38% for PEG-Lip-NF, Lip-NF, and NF, respectively). PEG-Lip-NF, compared to control, NF, and Lip-NF groups, was more efficacious by 45, 25, and 10%, respectively, to decrease the virulence of MSSA bacteremia through inhibiting the weight loss of the infected mice. Also, PEG-Lip-NF and Lip-NF, compared to control and NF groups, caused a considerable decrease in the mortality rate in a murine model of bacteremia (number of dead mice: 0, 0, 2, and 8 out of 15 for PEG-Lip-NF, Lip-NF, NF, and control groups, respectively). Overall, the results of this study demonstrated that the loading of NF into PEG-Lip is a promising strategy to decrease the side effects of NF with improved antibacterial effects for the treatment of MSSA biofilm-associated infections.

Prophylactic Treatment of Severe Haemophilia Á Patients with Inhibitors to FVIII with Peglip-FVIII

Background: FVIII replacement therapy is ineffective for severe haemophilia A (HA) patients who develop inhibitors to FVIII. Patients with intractable inhibitors currently require FVIII mimetics and/or bypassing agents to prevent bleeding. PEGylated liposomes (PEGLip) have been shown to protect FVIII from anti-FVIII antibodies in ex-vivo human studies and in combination with FVIII may present an option for the prophylactic treatment of inhibitor patients.Aims: To (a) demonstrate that PEGLip-FVIII administered intravenously (IV) to severe HA patients with history of inhibitors to FVIII enhances their clotting activity, (b) compare the number of bleeding episodes before and after PEG-Lip treatment, and (c) demonstrate that PEGLip-FVIII is well tolerated with no increase in inhibitor titres.Methods: Stage A: Four patients with a history of inhibitors were given single IV injections of PEGLip-FVIII (simoctocog alfa) at a dose of 22mg/kg PEGLip + 35 IU/kg FVIII and assessed for clotting activity at 0 hours (pre-injection) and at 20min, 1, 2, 4, 8, 24 hours, and daily thereafter up to 7 days using Rotational Thromboelastometry. Stage B: Patients received IV injections of PEGLip-FVIII for 6-weeks at a frequency determined by the investigator based on results obtained during Stage A. Inhibitor titres were monitored throughout.Results: Results are shown below.Treatment with PEGLip-FVIII was highly tolerated with no clinically significant changes in inhibitor titres. No Adverse Drug Reactions were reported. The mean frequency of administration of PEGLip-FVIII was every 5.7±1.4 days. The mean number of bleeding episodes reported during Stage B was 0.5±0.9 per month (due to 1 patient) compared with 0.9±0.4 per month recorded during the 24 weeks prior to enrollment.Conclusion: PEGLip-FVIII in inhibitor patients demonstrated efficacy in preventing spontaneous bleeds without increasing inhibitor titres, indicating a novel FVIII-based treatment for this cohort. Planned studies in a larger cohort may confirm our findings. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Liposomal Nanocarriers Designed for Sub-Endothelial Matrix Targeting under Vascular Flow Conditions.

Vascular interventions result in the disruption of the tunica intima and the exposure of sub-endothelial matrix proteins. Nanoparticles designed to bind to these exposed matrices could provide targeted drug delivery systems aimed at inhibiting dysfunctional vascular remodeling and improving intervention outcomes. Here, we present the progress in the development of targeted liposomal nanocarriers designed for preferential collagen IV binding under simulated static vascular flow conditions. PEGylated liposomes (PLPs), previously established as effective delivery systems in vascular cells types, served as non-targeting controls. Collagen-targeting liposomes (CT-PLPs) were formed by conjugating established collagen-binding peptides to modified lipid heads via click chemistry (CTL), and inserting them at varying mol% either at the time of PLP assembly or via micellar transfer. All groups included fluorescently labeled lipid species for imaging and quantification. Liposomes were exposed to collagen IV matrices statically or via hemodynamic flow, and binding was measured via fluorometric analyses. CT-PLPs formed with 5 mol% CTL at the time of assembly demonstrated the highest binding affinity to collagen IV under static conditions, while maintaining a nanoparticle characterization profile of ~50 nm size and a homogeneity polydispersity index (PDI) of ~0.2 favorable for clinical translation. When liposomes were exposed to collagen matrices within a pressurized flow system, empirically defined CT-PLPs demonstrated significant binding at shear stresses mimetic of physiological through pathological conditions in both the venous and arterial architectures. Furthermore, when human saphenous vein explants were perfused with liposomes within a closed bioreactor system, CT-PLPs demonstrated significant ex vivo binding to diseased vascular tissue. Ongoing studies aim to further develop CT-PLPs for controlled targeting in a rodent model of vascular injury. The CT-PLP nanocarriers established here show promise as the framework for a spatially controlled delivery platform for future application in targeted vascular therapeutics.

Effect of a Drug Delivery System Made of Quercetin Formulated into PEGylation Liposomes on Cervical Carcinoma In Vitro and In Vivo

Quercetin is a well-known flavonoid for its potent antitumor and antiproliferative effects on a wide range of human cancer cell lines. However, the delivery of quercetin is challenging due to its extreme insolubility in water. The intention of this study was to evaluate the antitumor effect of quercetin-loaded PEGylated liposomes (PEG-Que-NLs) in vitro and in vivo. We first prepared PEG-Que-NLs by method of thin film hydration; further determined, the optimum ratios of quercetin to Soybean phosphatidylcholine (SPC), to cholesterol (CHL), and to PEG-4000 were 1 : 8, 1 : 2, and 1 : 2 ( w / w ), respectively, and the optimal hydration temperature was 55°C when the mean vesicle diameter and apparent Zeta potential of PEG-Que-NLs were found to be 171.3 ± 10.4 nm and − 13.1 ± 2.1 mV, respectively; the encapsulation efficiency and the drug loading of PEG-Que-NLs were 81.25 ± 3.12 % and 8.5 ± 0.77 % , respectively. Drug release study in vitro showed that PEG-Que-NLs exhibited a slow-release effect without significant burst effect. Furthermore, the inhibition effect of PEG-Que-NLs on HeLa cells was considerably higher than free quercetin (free-Que) and quercetin liposomes (Que-NLs). Intravenous injection of PEG-Que-NLs into U14 bearing mouse models inhibited the cervical carcinoma growth significantly, and the tumor inhibition rate was much higher than free-Que and Que-NLs. These results of this study indicated that PEG-Que-NLs exhibited potential application prospects in the treatment of malignant tumors because of its tumor targeting, slow-release properties, and the solubility improvement of quercetin.

Advances in the Formulation and Assembly of Non-Cationic Lipid Nanoparticles for the Medical Application of Gene Therapeutics.

Lipid nanoparticles have become increasingly popular delivery platforms in the field of gene therapy, but bench-to-bedside success has been limited. Many liposomal gene vectors are comprised of synthetic cationic lipids, which are associated with lipid-induced cytotoxicity and immunogenicity. Natural, non-cationic PEGylated liposomes (PLPs) demonstrate favorable biocompatibility profiles but are not considered viable gene delivery vehicles due to inefficient nucleic acid loading and reduced cellular uptake. PLPs can be modified with cell-penetrating peptides (CPPs) to enhance the intracellular delivery of liposomal cargo but encapsulate leakage upon CPP-PLP assembly is problematic. Here, we aimed to identify parameters that overcome these performance barriers by incorporating nucleic acid condensers during CPP-PLP assembly and screening variable ethanol injection parameters for optimization. CPP-PLPs were formed with R8-amphiphiles via pre-insertion, post-insertion and post-conjugation techniques and liposomes were characterized for size, surface charge, homogeneity, siRNA encapsulation efficiency and retention and cell associative properties. Herein we demonstrate that pre-insertion of stearylated R8 into PLPs is an efficient method to produce non-cationic CPP-PLPs and we provide additional assembly parameter specifications for a modified ethanol injection technique that is optimized for siRNA encapsulation/retention and enhanced cell association. This assembly technique could provide improved clinical translation of liposomal based gene therapy applications.

Engineered versus hybrid cellular vesicles as efficient drug delivery systems: a comparative study with brain targeted vesicles.

Herein we elaborated on methods to load cellular vesicles (CVs) and to incorporate cholesterol (Chol) and PEG lipids in their membrane, for enhancing the potential of such engineered CVs (e-CVs) as drug carriers. Hybrids formed by fusion between PEGylated liposomes (PEG-LIP) and CVs were evaluated as alternatives to e-CV, for the first time. Freeze-thawing cycles (FT) and incubation protocols were tested, and vesicle fusion was monitored by FRET dilution. B16F10, hCMEC/D3, and LLC cells were used for e-CV or hybrid development, and FITC-dextran as a model hydrophilic drug. Results show that dehydration rehydration vesicle (DRV) method is optimal for highest CV loading and integrity, while optimal protocols for Chol/PEG enrichment were identified. FT was found to be more efficient than incubation for hybrid formation. Interestingly, despite their high Chol content, CVs had very low integrity that was not increased by enrichment with Chol, but only after PEG coating; e-CVs demonstrated higher integrity than hybrids. Vesicle uptake by hCMEC cells is in the order: LIP < e-CVs < Hybrids ≤ CVs (verified by confocal microscopy); the higher PEG content of e-CVs is possibly the reason for their reduced cell uptake. While CV and hybrid uptake are highly caveolin-dependent, e-CVs mostly follow clathrin-dependent pathways. In vivo and ex vivo results show that brain accumulation of hybrids is only slightly higher that of CVs, indicating that the surface PEG content of hybrids is not sufficient to prevent uptake by macrophages of the reticuloendothelial system. Taking together with the fact that subjection of CVs to FT cycles reduced their cellular uptake, it is concluded that PEGylated e-CVs are better than hybrids as brain-targeted drug carriers.