The encapsulation and release of guanosine from PEGylated liposomes

Er, Yan; Barnes, Timothy J.; Fornasiero, Daniel; Prestidge, Clive A.

doi:10.1080/08982100802673940

Cited by 36 publications

(21 citation statements)

References 31 publications

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“…Moreover, the PEGylated liposomes had higher retention capability than conventional liposomes therefore this is another reason for greater cytotoxicity of conventional against PEGylated liposomes. This greater retention capability of PEGylated liposomes has been reported by other researchers …”

Section: Discussionsupporting

confidence: 60%

Preparation, characterization, and in vitro evaluation of bleomycin‐containing nanoliposomes

et al. 2016

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Bleomycin is an anticancer drug used against various types of cancers. The aim of this study was to prepare a new PEGylated and non-PEGylated nanoliposomal formulation of bleomycin (PEG-nLip-BLM and nLip-BLM) and evaluate their anticancer activity in different tumor cell lines. The liposomes were prepared by thin-film hydration method, and then, bleomycin (BLM) was loaded to the prepared vesicles. The size, zeta potential, entrapment efficiency, loading rate, release profile, and cytotoxicity of liposomal formulations in TC-1, LLC1, and HFLF-PI5 cell lines were investigated. Mean particle size and zeta potential of the PEG-nLip-BLM and nLip-BLM were found to be 99.4 ± 4.6 nm and -34.83 ± 4.7 mV; and 112.2 ± 7.2 nm and -27.5 ± 3.2 mV, respectively, which were stable for at least 2 months. Encapsulation and loading efficiency of BLM for PEG-nLip-BLM and nLip-BLM were obtained about 83.1 ± 4.2% and 14.3 ± 2.5%; and 78.3 ± 8.6% and 11.1 ± 3.3%, respectively. Drug release study showed a slow release pattern without considerable burst effect. The liposomal formulations indicated lower toxicity compared to free drug in case of TC-1 and HFLF-PI5 cells, but their cytotoxicity against LLC1 cells was significantly higher than free drug. The results of this study indicated that PEG-nLip-BLM can be a suitable candidate for drug delivery to solid tumors.

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Section: Discussionsupporting

confidence: 60%

Preparation, characterization, and in vitro evaluation of bleomycin‐containing nanoliposomes

et al. 2016

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“…In addition to the steric stabilization, PEG-phospholipids also influence the liposome permeability and the rate and mechanism of drug release [52]. For instance, the increase in DMPE-PEG level in the liposomes was found to significantly reduce the release rate constant of encapsulated guanosine [53]. The investigators also found that the mechanism of guanosine release changed from diffusion-controlled to interfacial-controlled, as the amount of PEG-phospholipid in the bilayer was increased, and the magnitude of the effect was directly dependent on the MW of PEG [53].…”

Section: Poly(ethylene Glycol)-linked-lipids (Peg-lipids)mentioning

confidence: 99%

Surface Engineering of Liposomes for Stealth Behavior

2013

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Liposomes are used as a delivery vehicle for drug molecules and imaging agents. The major impetus in their biomedical applications comes from the ability to prolong their circulation half-life after administration. Conventional liposomes are easily recognized by the mononuclear phagocyte system and are rapidly cleared from the blood stream. Modification of the liposomal surface with hydrophilic polymers delays the elimination process by endowing them with stealth properties. In recent times, the development of various materials for surface engineering of liposomes and other nanomaterials has made remarkable progress. Poly(ethylene glycol)-linked phospholipids (PEG-PLs) are the best representatives of such materials. Although PEG-PLs have served the formulation scientists amazingly well, closer scrutiny has uncovered a few shortcomings, especially pertaining to immunogenicity and pharmaceutical characteristics (drug loading, targeting, etc.) of PEG. On the other hand, researchers have also begun questioning the biological behavior of the phospholipid portion in PEG-PLs. Consequently, stealth lipopolymers consisting of non-phospholipids and PEG-alternatives are being developed. These novel lipopolymers offer the potential advantages of structural versatility, reduced complement activation, greater stability, flexible handling and storage procedures and low cost. In this article, we review the materials available as alternatives to PEG and PEG-lipopolymers for effective surface modification of liposomes.

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“…This formulation achieved an encapsulation efficiency of ~50%. Only 3.3 mol% of PEG 2000 was used in this study as a higher PEG content is known to reduce adsorption of liposomes onto cells [41]. …”

Section: Discussionmentioning

confidence: 99%

Development of a novel cell-based assay system EPISSAY for screening epigenetic drugs and liposome formulated decitabine

et al. 2013

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BackgroundDespite the potential of improving the delivery of epigenetic drugs, the subsequent assessment of changes in their epigenetic activity is largely dependent on the availability of a suitable and rapid screening bioassay. Here, we describe a cell-based assay system for screening gene reactivation.MethodsA cell-based assay system (EPISSAY) was designed based on a silenced triple-mutated bacterial nitroreductase TMnfsB fused with Red-Fluorescent Protein (RFP) expressed in the non-malignant human breast cell line MCF10A. EPISSAY was validated using the target gene TXNIP, which has previously been shown to respond to epigenetic drugs. The potency of a epigenetic drug model, decitabine, formulated with PEGylated liposomes was also validated using this assay system.ResultsFollowing treatment with DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors such as decitabine and vorinostat, increases in RFP expression were observed, indicating expression of RFP-TMnfsB. The EPISSAY system was then used to test the potency of decitabine, before and after PEGylated liposomal encapsulation. We observed a 50% higher potency of decitabine when encapsulated in PEGylated liposomes, which is likely to be due to its protection from rapid degradation.ConclusionsThe EPISSAY bioassay system provides a novel and rapid system to compare the efficiencies of existing and newly formulated drugs that reactivate gene expression.

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The encapsulation and release of guanosine from PEGylated liposomes

Cited by 36 publications

References 31 publications

Preparation, characterization, and in vitro evaluation of bleomycin‐containing nanoliposomes

Preparation, characterization, and in vitro evaluation of bleomycin‐containing nanoliposomes

Surface Engineering of Liposomes for Stealth Behavior

Development of a novel cell-based assay system EPISSAY for screening epigenetic drugs and liposome formulated decitabine

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