Bioadhesive, collagen-modified liposomes: molecular and cellular level studies on the kinetics of drug release and on binding to cell monolayers

Yerushalmi, Noga; Margalit, Rimona

doi:10.1016/0005-2736(94)90274-7

Cited by 37 publications

(37 citation statements)

References 18 publications

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“…The release rates were measured in sink conditions; otherwise, the evaluation of the drug release from liposomal dispersions will be problematic due to the dependence of the analysis from the test conditions [50]. In the traditional dialysis technique, the carrier is suspended in a small volume of continuous phase and separated from a sink solution by permeable dialysis membrane [51], providing a physical separation between nanoparticles and free drug at various time points during the kinetic study. The validation of the drug release model was obtained making assumptions to justify the mathematical model used, for example: (1) analysis is based on one-dimensional diffusion; thus, edge effects must be negligible; (2) the suspended drug is in a fine state that particles are much smaller in diameter than the thickness of the system; (3) the diffusivity of the drug is constant; (4) perfect sink conditions are maintained; and (5) the appearance of drug in the Bsink^is the result of the diffusion from the nanoparticles followed by diffusion across the dialysis membrane (although it is generally treated as a simple first-order process).…”

Section: Drug Releasementioning

confidence: 99%

Influence of cholesterol on liposome stability and on in vitro drug release

Briuglia

Rotella

McFarlane

et al. 2015

Drug Deliv. and Transl. Res.

515

268

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Cholesterol plays a strategic role in liposome composition; however, the quantity used to achieve an appropriate formulation has not been yet clarified. Therefore, by screening arrangement of lipids and cholesterol ratio, the main aim of this study is to investigate the most suitable amount of cholesterol in lipids in order to prepare stable and controlled drug release vehicles. For the preparation of liposomes, DMPC, DPPC and DSPC phospholipids were used and combined with different molar ratios of cholesterol (e.g. 100, 80-20, 70-30, 60-40 and 50-50%). Stability studies were conducted by storing the formulations at 37 and 50 °C for 30 days and by analysing them by AFM, DLS and FT-IR. By detecting the two most stable formulations from the stability results, drug encapsulation and in vitro release studies in PBS were performed by encapsulating atenolol and quinine. The release results were validated using a simulation model to ensure the reliability and suitable interpretation of the data. The generated model showed a good correlation between the prediction and the in vitro obtained results. By using 70:30% ratio (known in literature as 2:1), it is possible to reach the most stable formulation to guarantee a controlled and reproducible release for drugs with different physicochemical characteristics and pharmaceutical applications.

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Section: Drug Releasementioning

confidence: 99%

Influence of cholesterol on liposome stability and on in vitro drug release

Briuglia

Rotella

McFarlane

et al. 2015

Drug Deliv. and Transl. Res.

515

268

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“…These similarities may be attributed to drug diffusion from intact liposomes under the extremely low liposome concentrations being assayed. The general phenomena of an inverse relationship between the kinetics of drug release and liposome concentration 24,25,29 indicates that complete and fast depletion of the liposomes can take place under the conditions of the assay, where the liposome concentrations in the samples plated onto the disks are extremely low, with dilution factors ranging from 1 × 10 4 to 2 × 10 3 . Finally, the encapsulated ampicillin was active against bacterial colonies residing outside cells.…”

Section: Resultsmentioning

confidence: 99%

“…Liposome Preparation and Drug Encapsulationsmultilamellar liposomes (multilamellar vesicles, MLV) were prepared as previously described [24][25][26][27][28][29] from lipid compositions of PC:CH at 3:1 mole ratios. Briefly, the lipids were dissolved in a methanol:chloroform (1:2, v/v) solution in a round-bottomed flask, and the organic solvent was evaporated to dryness under low pressure in a rotary evaporator.…”

Section: Introductionmentioning

confidence: 99%

“…[24][25][26][27][28][29] Briefly, a suspension of liposomes (1.0 mL) was placed in a dialysis sac that was immersed in a constantly stirred receiver vessel containing 10 mL of drug-free buffer (PBS). At designated periods, the dialysis sac was moved from one receiver vessel to another containing fresh (i.e., drug-free) buffer.…”

Section: Introductionmentioning

confidence: 99%

“…Efficiency of Drug EncapsulationsThe efficiency of drug encapsulation, defined as the fraction of the total drug in the system encapsulated within the liposomes, was determined by centrifugation [24][25][26][27][28][29] and by processing data of kinetic studies. Samples of the liposome preparation were subjected to high-speed centrifugation.…”

Section: Introductionmentioning

confidence: 99%

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Liposome-Encapsulated Ampicillin: Physicochemical and Antibacterial Properties

Schumacher

Margalit

1997

Journal of Pharmaceutical Sciences

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The objectives of this study were to develop high-performance liquid chromatography (HPLC) and antibacterial assays for ampicillin encapsulated in multilamellar liposomes (MLV) and investigate the physicochemical and antibacterial properties of ampicillin-liposome systems. The major findings were fourfold. First, ammonium acetate (0.575%) in methanol:water (450:550; v/v), adjusted to pH 7.2, was suitable as the mobile phase for the HPLC determinations of ampicillin in both aqueous and liposomal systems. This mobile phase also provided (alone or with additional methanol) complete dissolution of liposomal assay samples in a precolumn treatment that made all of the encapsulated drug available for chromatography. Multiple samples were assayed without any technical limitations. Second, the growth-inhibition antibacterial assay developed, which used the USP test organism Micrococcus Luteus and paper disks, was quantitative for both free and liposome-encapsulated ampicillin. Third, the physicochemical properties of encapsulated ampicillin include encapsulation efficiencies of 10 to 50% for liposome concentrations in the range 10-200 mM (lipid), and a single rate constant to sufficiently and quantitatively describe the diffusion of encapsulated ampicillin, with half-lives in the range of 40 h. Fourth, the biological properties include the first direct evidence that encapsulated ampicillin retains full biological activity; that is, liposome-encapsulated ampicillin was active against extracellular bacterial colonies of Micrococcus luteus. Furthermore, encapsulation enhanced ampicillin stability. For example, free ampicillin in an aqueous solution that was stored for 5 weeks at 4 degrees C lost 50% of its initial activity, whereas liposome-encapsulated ampicillin (freed from unencapsulated drug) stored under the same conditions lost only 17% of its initial activity. The findings of this study, provide strong support for ampicillin-liposome formulations as valid dosage forms for this drug that are worthy of further experimental evaluations.

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Liposomes and Drug Delivery

Antimisiaris

Kallinteri

Fatouros³

2010

Pharmaceutical Sciences Encyclopedia

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Liposomes are vesicles in which an aqueous volume is entirely surrounded by a phospholipid membrane and their size can range between 30 and 50 nm up to several micrometers. Liposomes serve as a drug delivery system because of their versatile structure and because they are nontoxic, nonimmunogenic, and fully biodegradable. This chapter focuses on basic characteristics and applications of liposomes, their fate after in vivo administration by different routes, and other possible routes for in vivo administration of liposomes.

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Bioadhesive, collagen-modified liposomes: molecular and cellular level studies on the kinetics of drug release and on binding to cell monolayers

Cited by 37 publications

References 18 publications

Influence of cholesterol on liposome stability and on in vitro drug release

Influence of cholesterol on liposome stability and on in vitro drug release

Liposome-Encapsulated Ampicillin: Physicochemical and Antibacterial Properties

Liposomes and Drug Delivery

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