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Ph sensitive liposomes

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https://www.readbyqxmd.com/read/29019266/liposome-loaded-thermo-sensitive-hydrogel-for-stabilization-of-sn-38-via-intratumoral-injection-optimization-characterization-and-antitumor-activity
#1
Ruixue Bai, Xueqing Deng, Qiong Wu, Xiaomian Cao, Tiantian Ye, Shujun Wang
Main challenges of the clinical use of 7-ethyl-10-hydroxycamptothecin (SN-38) are its facile transition between the active lactone form (SN-38A) and the inactive carboxylate form (SN-38I) under physiological conditions and its low solubility. The purpose of this study was to develop a thermo-sensitive hydrogel system with acidic SN-38 liposomes (SN-38-Lip-Gel) for local chemotherapy to solve these problems and to evaluate its antitumor activity and tissue distribution in tumor-bearing mice. A study of structural conversion between SN-38I and SN-38A under various pH conditions indicated that acidic solution could inhibit the conversion...
October 11, 2017: Pharmaceutical Development and Technology
https://www.readbyqxmd.com/read/28972792/a-nano-liposome-vaccine-carrying-e75-a-her-2-neu-derived-peptide-exhibits-significant-anti-tumor-activity-in-mice
#2
Atefeh Arab, Javad Behravan, Atefeh Razazan, Zahra Gholizadeh, Amin Reza Nikpoor, Nastaran Barati, Fatemeh Mosaffa, Ali Badiee, Mahmoud Reza Jaafari
E75 (HER-2/neu-369-377), is an immunogenic peptide which is highly expressed in breast cancer patients. The purpose of this study was to develop an effective vaccine delivery/adjuvant system by attachment of this peptide to the surface of liposomes consisting of phospholipids including DSPC and DSPG with high transition temperature (Tm) and DOPE (a pH-sensitive lipid for cytosolic antigen delivery) to improve anti-tumor immune activity against the E75 peptide. For this purpose, the E75 peptide was incorporated into liposomes consisting of DSPC/DSPG/Chol/DOPE (15/2/3/5 molar ratio) through conjugation with maleimide-PEG2000-DSPE...
October 3, 2017: Journal of Drug Targeting
https://www.readbyqxmd.com/read/28965079/ngr-modified-ph-sensitive-liposomes-for-controlled-release-and-tumor-target-delivery-of-docetaxel
#3
Zili Gu, Minglu Chang, Yang Fan, Yanbin Shi, Guimei Lin
As current tumor chemotherapy faces many challenges, it is important to develop drug delivery systems with increased tumor-targeting ability, enhanced therapeutic effects and reduced side effects. In this study, a pH-sensitive liposome was constructed containing CHEMS-anchored PEG2000 for extended circulation and NGR peptide as the targeting moiety. The NGR-modified docetaxel-loaded pH-sensitive extended-circulation liposomes (DTX/NGR-PLL) prepared possess suitable physiochemical properties, including particle size of approximately 200nm, drug encapsulation efficiency of approximately 70%, and pH-sensitive drug release properties...
September 23, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28836126/effects-of-micro-environmental-ph-of-liposome-on-chemical-stability-of-loaded-drug
#4
Xiao-Ru Shao, Xue-Qin Wei, Shu Zhang, Na Fu, Yun-Feng Lin, Xiao-Xiao Cai, Qiang Peng
Liposome is a promising carrier system for delivering bioactive molecules. However, the successful delivery of pH-sensitive molecules is still limited by the intrinsic instability of payloads in physiological environment. Herein, we developed a special liposome system that possesses an acidic micro-environment in the internal aqueous chamber to improve the chemical stability of pH-sensitive payloads. Curcumin-loaded liposomes (Cur-LPs) with varied internal pH values (pH 2.5, 5.0, or 7.4) were prepared. These Cur-LPs have similar particle size of 300 nm, comparable physical stabilities and analogous in vitro release profiles...
August 23, 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28799758/ph-sensitive-interactions-between-cellulose-nanocrystals-and-dopc-liposomes
#5
Yotam Navon, Harisoa Radavidson, Jean-Luc Putaux, Bruno Jean, Laurent Heux
The interaction of 1,2 dioleolyl-sn-glycero-3-phosphatidylcholine (DOPC) vesicles with cellulose nanocrystals (CNCs) using several complementary techniques. Dynamic light scattering, zeta-potential, cryo-transmission electron microscopy and isothermal titration calorimetry (ITC) analyses confirmed the formation of pH-dependent CNC-liposome complexes. ITC was used to characterize the thermodynamic properties of this interaction. Positive values of enthalpy were found at pH lower than 5 where the charge sign of the constituents was opposite...
August 29, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28779980/secretion-induces-cell-ph-dynamics-impacting-assembly-disassembly-of-the-fusion-protein-complex-a-combined-fluorescence-and-atomic-force-microscopy-study
#6
REVIEW
Kenneth T Lewis, Akshata R Naik, Suvra S Laha, Sunxi Wang, Guangzhao Mao, Eric Kuhn, Bhanu P Jena
A wide range of cellular activities including protein folding and cell secretion, such as neurotransmission or insulin release, are all governed by intracellular pH homeostasis, underscoring the importance of pH on critical life processes. Nano- scale pH measurements of cells and biomolecules therefore hold great promise in understanding a plethora of cellular functions, in addition to disease detection and therapy. In the current study, a novel approach using cadmium telluride quantum dots (CdTeQDs) as pH sensors, combined with fluorescent imaging, spectrofluorimetry, atomic force microscopy (AFM), and Western blot analysis, enabled the study of intracellular pH dynamics at 1 milli-pH sensitivity and 80nm pixel resolution, during insulin secretion...
August 2, 2017: Seminars in Cell & Developmental Biology
https://www.readbyqxmd.com/read/28777336/development-of-ph-sensitive-dextran-derivatives-with-strong-adjuvant-function-and-their-application-to-antigen-delivery
#7
Eiji Yuba, Shinya Uesugi, Maiko Miyazaki, Yuna Kado, Atsushi Harada, Kenji Kono
To achieve efficient cancer immunotherapy, the induction of cytotoxic T lymphocyte-based cellular immunity is necessary. In order to induce cellular immunity, antigen carriers that can deliver antigen into cytosol of antigen presenting cells and can activate these cells are required. We previously developed 3-methyl glutarylated dextran (MGlu-Dex) for cytoplasmic delivery of antigen via membrane disruption ability at weakly acidic pH in endosome/lysosomes. MGlu-Dex-modified liposomes delivered model antigens into cytosol of dendritic cells and induced antigen-specific cellular immunity...
August 4, 2017: Membranes
https://www.readbyqxmd.com/read/28762066/zeta-potential-a-case-study-of-cationic-anionic-and-neutral-liposomes
#8
Mackensie C Smith, Rachael M Crist, Jeffrey D Clogston, Scott E McNeil
Zeta potential is often used to approximate a nanoparticle's surface charge, i.e., cationic, anionic, or neutral character, and has become a standard characterization technique to evaluate nanoparticle surfaces. While useful, zeta potential values provide only very general conclusions about surface charge character. Without a thorough understanding of the measurement parameters and limitations of the technique, these values can become meaningless. This case study attempts to explore the sensitivity of zeta potential measurement using specifically formulated cationic, anionic, and neutral liposomes...
July 31, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28704679/ph-sensitive-polymer-modified-liposome-based-immunity-inducing-system-effects-of-inclusion-of-cationic-lipid-and-cpg-dna
#9
Yuta Yoshizaki, Eiji Yuba, Naoki Sakaguchi, Kazunori Koiwai, Atsushi Harada, Kenji Kono
Efficient vaccine carriers for cancer immunotherapy require two functions: antigen delivery to dendritic cells (DCs) and the activation of DCs, a so-called adjuvant effect. We previously reported antigen delivery system using liposomes modified with pH-sensitive polymers, such as 3-methylglutarylated hyperbranched poly(glycidol) (MGlu-HPG), for the induction of antigen-specific immune responses. We reported that inclusion of cationic lipids to MGlu-HPG-modified liposomes activates DCs and enhances antitumor effects...
July 3, 2017: Biomaterials
https://www.readbyqxmd.com/read/28671767/emergence-of-gold-mesoporous-silica-hybrid-nanotheranostics-dox-encoded-folate-targeted-chemotherapy-with-modulation-of-sers-fingerprinting-for-apoptosis-toward-tumor-eradication
#10
Adukkadan N Ramya, Manu M Joseph, Santhi Maniganda, Varsha Karunakaran, Sreelekha T T, Kaustabh Kumar Maiti
Strategically fabricated theranostic nanocarrier delivery system is an unmet need in personalized medicine. Herein, this study reports a versatile folate receptor (FR) targeted nanoenvelop delivery system (TNEDS) fabricated with gold core silica shell followed by chitosan-folic acid conjugate surface functionalization by for precise loading of doxorubicin (Dox), resembled as Au@SiO2 -Dox-CS-FA. TNEDS possesses up to 90% Dox loading efficiency and internalized through endocytosis pathway leading to pH and redox-sensitive release kinetics...
July 3, 2017: Small
https://www.readbyqxmd.com/read/28638626/effects-of-liposomal-curcumin-on-five-opportunistic-bacterial-strains-found-in-the-equine-hindgut-preliminary-study
#11
S D Bland, E B Venable, J L McPherson, R L Atkinson
BACKGROUND: The horse intestinal tract is sensitive and contains a highly complex microbial population. A shift in the microbial population can lead to various issues such as inflammation and colic. The use of nutraceuticals in the equine industry is on the rise and curcumin is thought to possess antimicrobial properties that may help to minimize the proliferation of opportunistic bacteria. METHODS: Four cecally-cannulated horses were utilized to determine the optimal dose of liposomal-curcumin (LIPC) on reducing Streptococcus bovis/equinus complex (SBEC), Escherichia coli K-12, Escherichia coli general, Clostridium difficile, and Clostridium perfringens in the equine hindgut without adversely affecting cecal characteristics...
2017: Journal of Animal Science and Technology
https://www.readbyqxmd.com/read/28580308/a-novel-approach-on-drug-delivery-investigation-of-a-new-nano-formulation-of-liposomal-doxorubicin-and-biological-evaluation-of-entrapped-doxorubicin-on-various-osteosarcoma-cell-lines
#12
Fateme Haghiralsadat, Ghasem Amoabediny, Mohammad Hasan Sheikhha, Tymour Forouzanfar, Marco N Helder, Behrouz Zandieh-Doulabi
OBJECTIVE: In this study we prepared a novel formulation of liposomal doxorubicin (L- DOX). The drug dose was optimized by analyses of cellular uptake and cell viability of osteosarcoma (OS) cell lines upon exposure to nanoliposomes that contained varying DOX concentrations. We intended to reduce the cytotoxicity of DOX and improve characteristics of the nanosystems. MATERIALS AND METHODS: In this experimental study, we prepared liposomes by the pH gradient hydration method...
2017: Cell Journal
https://www.readbyqxmd.com/read/28546107/intestinal-toxicity-evaluation-of-long-circulating-and-ph-sensitive-liposomes-loaded-with-cisplatin
#13
Raquel Silva Araújo, Ana Letícia Malheiros Silveira, Éricka Lorenna de Sales E Souza, Rachel Horta Freire, Cristina Maria de Souza, Diego Carlos Reis, Bruno Rocha Cordeiro Costa, Michelle Amantéa Sugimoto, Josianne Nicácio Silveira, Flaviano Dos Santos Martins, Geovanni Dantas Cassali, Jacqueline Isaura Alvarez Leite, Lirlândia Pires Sousa, Adaliene Versiani Matos Ferreira, Mônica Cristina Oliveira, Valbert Nascimento Cardoso
Cisplatin (CDDP) is a chemotherapeutic agent widely used in several anticancer protocols for instance head and neck, testicle, ovarian, lung and peritoneal carcinomatosis. According to the literature, the use of CDDP is associated with several side effects; among them, we highlighted the mucositis. CDDP, when administered by IP, promoted significant intestinal epithelium alterations in an experimental model. Our research group has proposed that the incorporation of CDDP into long-circulating and pH-sensitive liposomes (SpHL-CDDP) could help to overcome some side effects induced by this drug...
August 30, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28528212/targeted-co-delivery-of-polypyrrole-and-rapamycin-by-trastuzumab-conjugated-liposomes-for-combined-chemo-photothermal-therapy
#14
Hanh Thuy Nguyen, Tuan Hiep Tran, Raj Kumar Thapa, Cao Dai Phung, Beom Soo Shin, Jee-Heon Jeong, Han-Gon Choi, Chul Soon Yong, Jong Oh Kim
Trastuzumab is a therapeutic monoclonal antibody that selectively recognizes HER2/neu receptor for targeting breast cancers. In this study, we aimed to present a strategy to combine chemo and phototherapy and targeted delivery via monoclonal antibody for enhanced anticancer effects. We co-loaded a chemotherapeutic agent, rapamycin, and a photosensitizer, polypyrrole, in trastuzumab-conjugated liposomes (LRPmAb) for combined chemo-photothermal therapy. LRPmAb had small size (172.2±9.6nm), narrow distribution, and negative ζ-potential (-12...
May 18, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28493521/a-freeze-concentration-and-polyampholyte-modified-liposome-based-antigen-delivery-system-for-effective-immunotherapy
#15
Sana Ahmed, Satoshi Fujita, Kazuaki Matsumura
Immunotherapy is an exciting new approach to cancer treatment. The development of a novel freeze-concentration method is described that could be applicable in immunotherapy. The method involves freezing cells in the presence of pH-sensitive, polyampholyte-modified liposomes with encapsulated ovalbumin (OVA) as the antigen. In RAW 264.7 cells, compared to unfrozen, freeze-concentration of polyampholyte-modified liposomes encapsulating OVA resulted in efficient OVA uptake and also allowed its delivery to the cytosol...
May 11, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28471676/protonation-kinetics-compromise-liposomal-fluorescence-assay-of-membrane-permeation
#16
Deniz Sezer, Tuğçe Oruç
The membrane permeation of weak acids and bases couples to the ambient pH and can be studied using pH-sensitive dyes as reporters. Such fluorescence measurements with aliphatic amine drugs have revealed biexponential kinetics of permeation into liposomes (Eyer et al. J. Controlled Release 2014, 173, 102). Permeability coefficients have been obtained using the faster of the two kinetic components. Here, the origin of the biexponential kinetics is studied with a kinetic rate model that in addition to drug permeation accounts for the protonation of the drug and the dye...
May 16, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28463812/preparation-of-dual-stimuli-responsive-liposomes-using-methacrylate-based-copolymers-with-ph-and-temperature-sensitivities-for-precisely-controlled-release
#17
Takumi Sugimoto, Naoko Yamazaki, Takaaki Hayashi, Eiji Yuba, Atsushi Harada, Aki Kotaka, Chiharu Shinde, Takayuki Kumei, Yasushi Sumida, Mitsuhiro Fukushima, Yuki Munekata, Keiichi Maruyama, Kenji Kono
Dual-signal-sensitive copolymers were synthesized by copolymerization of methoxy diethylene glycol methacrylate, methacrylic acid, and lauroxy tetraethylene glycol methacrylate, which respectively provide temperature sensitivity, pH sensitivity, and anchoring to liposome surfaces. These novel copolymers, with water solubility that differs depending on temperature and pH, are soluble in water under neutral pH and low-temperature conditions, but they become water-insoluble and form aggregates under acidic pH and high-temperature conditions...
April 23, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28452577/novel-nano-sized-liposome-encapsulated-polyamidoamine-dendrimer-derivatives-facilitate-tumour-targeting-by-overcoming-the-polyethylene-glycol-dilemma-and-integrin-saturation-obstacle
#18
Gang Li, Yan-Zhi Song, Zhen-Jun Huang, Kang Chen, Da-Wei Chen, Yi-Hui Deng
Drug delivery systems (DDSs) commonly employ arginine-glycine-aspartic acid (RGD) peptides with polyethylene glycol (PEG)-dependent enhanced permeability and retention (EPR) effect to optimise tumour-targeting. However, the PEG dilemma and integrin saturation obstacle are major challenges. To address these issues, we constructed a novel, nano-sized DDS by encapsulating doxorubicin (DOX)-loaded folic acid derivatives of polyamidoamine dendrimer (PAMAM G5.0) in cyclic RGD-tyrosine-lysine pentapeptide (c[RGDyK])-modified liposomes (RGD-SL[FND/DOX]), prepared using thin-film hydration, film-dispersion and hydration-sonication...
September 2017: Journal of Drug Targeting
https://www.readbyqxmd.com/read/28442909/tat-functionalized-liposomes-for-the-treatment-of-meningitis-an-in-vitro-study
#19
Caterina Bartomeu Garcia, Di Shi, Thomas J Webster
Bacterial meningitis has become a global concern, because of the emergence of antibiotic-resistant bacteria. It has been demonstrated that liposomes can enter bacteria, thus providing a possible treatment for numerous infections, including meningitis. Fusogenic liposomes are pH-sensitive with a high capacity to fuse with the bacteria membrane and promote intracellular drug release. Moreover, this ability can be improved by using cell-penetrating peptides (such as Tat47-57, which is a peptide derived from the Tat protein of HIV)...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28415842/spectrophotometric-quantification-of-peroxidase-with-p-phenylene-diamine-for-analyzing-peroxidase-encapsulating-lipid-vesicles
#20
Ya Zhang, Yannick R F Schmid, Sandra Luginbühl, Qiang Wang, Petra S Dittrich, Peter Walde
A spectrophotometric assay for the determination of horseradish peroxidase (HRP) in aqueous solution with p-phenylenediamine (PPD, benzene-1,4-diamine) as electron donor substrate and hydrogen peroxide (H2O2) as oxidant was developed. The oxidation of PPD by HRP/H2O2 leads to the formation of Bandrowski's base ((3E,6E)-3,6-bis[(4-aminophenyl)imino]cyclohexa-1,4-diene-1,4-diamine), which can be quantified by following the increase in absorbance at 500 nm. The assay was applied for monitoring the activity of HRP inside ≈180 nm-sized lipid vesicles (liposomes), prepared from POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and purified by size exclusion chromatography...
May 3, 2017: Analytical Chemistry
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