Formulation parameters of fluoroquinolone-loaded liposomes and in vitro antimicrobial activity

Puglisi, Giovanni; Fresta, Massimo; Mazzone, G; Furneri, Pio Maria; Tempera, G

doi:10.1016/0378-5173(94)00340-b

Cited by 41 publications

(23 citation statements)

References 21 publications

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“…They reported a gentamicin encapsulation capacity in the anionicformulation DOPE/DOPS/PEG at a level of 2.8%. The encapsulation efficiency of the drug was thus relatively low, but similar results were obtained by other investigators [20,30,31]. No noticeable differences in encapsulation efficiency were observed in relation to the composition, fluidity, or charge of the liposomes.…”

Section: Resultssupporting

confidence: 72%

A comparison of the in vitro antimicrobial activity of liposomes containing meropenem and gentamicin

Drulis-Kawa

Gubernator

Dorotkiewicz-Jach

et al. 2006

Cellular and Molecular Biology Letters

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Mueller Hinton II Broth; MLVs -the multilamellar vesicles; MIC -minimum inhibitory concentration; MPS -the mononuclear phagocytic system; NBS -normal bovine serum; NCCLS -National Committee for Clinical Laboratory Standards; OPA -o-phthaldialdehyde; PBSphosphate-buffered solution; PC -phosphatidylcholine, PI--phosphatidyl inositol; SAoctadecylamine; ULVs -unilamellar vesicles. A COMPARISON OF THE in vitro ANTIMICROBIAL ACTIVITY OF LIPOSOMES CONTAINING MEROPENEM AND GENTAMICINZUZANNA Abstract: The antimicrobial activity of eight cationic, two neutral and three anionic liposome compositions containing meropenem and gentamicin was tested in vitro in broth and serum medium. The cationic formulations showed better antibacterial efficacy against both Gram-positive and Gram-negative bacteria than the anionic and neutral ones, regardless of the encapsulated drug. The most effective formulations were the cationic PC/DOPE/DOTAP 3:4:3 and PC/Chol/DOTAP 3:4:3, as the MICs with meropenem were 2 to 4 times lower than those of the free drug.

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Section: Resultssupporting

confidence: 72%

A comparison of the in vitro antimicrobial activity of liposomes containing meropenem and gentamicin

Drulis-Kawa

Gubernator

Dorotkiewicz-Jach

et al. 2006

Cellular and Molecular Biology Letters

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“…This behavior could be due to the presence of the charged phospholipids leading to a slight increase in size of liposomes, thus due to the interlamellar electrostatic repulsion forces that lead to an enhancement of the captured water phase (43). This effect appears in MLVs more than in REVs, which are poorly influenced by the presence of charged phospholipids, owing to the presence of one lamellae per vesicle.…”

Section: Factors Affecting Encapsulation Efficiencymentioning

confidence: 97%

“…This result may be because the encapsulation of ofloxacin depends on the fluidity of the phospholipids bilayer; the lower the fluidity, the greater the EE%. DPPC is a synthetic product that has higher phase transition temperature (42.5±0.25°C) than egg PC (−7°C) (43), so the fluidity of DPPC is less than egg PC; this leads to an increase EE% in the case of liposomes containing DPPC. Concerning the effect of CH content on EE% of ofloxacin in liposomes, results showed that the EE% increases by increasing the CH content until a certain limit, above which the EE% decreases by increasing CH concentration.…”

Section: Factors Affecting Encapsulation Efficiencymentioning

confidence: 99%

Preparation and Evaluation of Thermosensitive Liposomal Hydrogel for Enhanced Transcorneal Permeation of Ofloxacin

Hosny

2009

AAPS PharmSciTech

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Abstract. Ofloxacin, available as ophthalmic solution, has two major problems: first, it needs frequent administration every 4 hours or even every 1 hour to treat severe eye infection; second, there is formation of white crystalline deposit on cornea due to its pH-dependent solubility, which is very low at pH of corneal fluid. In order to provide a solution to previous problems, ofloxacin in this study is prepared as topically effective in situ thermosensitive prolonged release liposomal hydrogel. Two preparation procedures were carried out, leading to the formation of multilamellar vesicles (MLVs) and reverse-phase evaporation vesicles (REVs) at pH 7.4. Effects of method of preparation, lipid content, and charge inducers on encapsulation efficiency were studied. For the preparation of in situ thermosensitive hydrogel, chitosan/β-glycerophosphate system was synthesized and used as carrier for ofloxacin liposomes. The effect of addition of liposomes on gelation temperature, gelation time, and rheological behaviors of the hydrogel were evaluated. In vitro transcorneal permeation was also determined. MLVs entrapped greater amount of ofloxacin than REVs liposomes at pH 7.4; drug loading was increased by including charge-inducing agent and by increasing cholesterol content until a certain limit. The gelation time was decreased by the addition of liposomes into the hydrogel. The prepared liposomal hydrogel enhances the transcorneal permeation sevenfold more than the aqueous solution. These results suggested that the in situ thermosensitive ofloxacin liposomal hydrogel ensures steady and prolonged transcorneal permeation, which improves the ocular bioavailability, minimizes the need for frequent administration, and decreases the ocular side effect of ofloxacin.

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“…Our preliminary experiments demonstrated that ofloxacin-loaded liposomes showed an antibacterial activity that was the same as or better than that of the free drug (45). Moreover, the liposome formulation was able to deliver ofloxacin into McCoy cells in a greater amount (2.6-fold) than the free drug, improving antibiotic accumulation (16).…”

mentioning

confidence: 95%

“…The liposome suspension containing ofloxacin was added in order to obtain an equivalent drug concentration with respect to that of the free drug solution, thus making the direct comparison of the results possible to evaluate the effectiveness of the liposome carrier. Mueller-Hinton broth was replaced by Iso-Sensitest broth (Oxoid, Basingstoke, United Kingdom) as previously described (45). Stock solutions of liposomo-ofloxacin (2,560 g/ml in Iso-Senstitest broth) and ofloxacin (512 g/ml in Iso-Sensitest from an original stock in water at 5,120 g/ml) were prepared and diluted as proposed by National Committee for Clinical Laboratory Standards (37).…”

mentioning

confidence: 99%

Ofloxacin-Loaded Liposomes: In Vitro Activity and Drug Accumulation in Bacteria

Furneri¹,

Fresta

Puglisi

et al. 2000

Antimicrob Agents Chemother

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Different ofloxacin-loaded unilamellar vesicles were prepared by the extrusion technique, and their antimicrobial activities were determined in comparison to those of the free drug by means of MIC determinations with both American Type Culture Collection standards and wild-type bacterial strains (six strains of Enterococcus faecalis, seven strains of Escherichia coli, six strains of Staphylococcus aureus, and six strains of Pseudomonas aeruginosa). The accumulation of ofloxacin and liposome-ofloxacin was measured by determining the amount of the drug inside the bacteria as a function of time. Encapsulated fluoroquinolone yielded MICs which were at least twofold lower than those obtained with the free drug. In particular, liposomes made up of dimyristoylphosphatidylcholine-cholesterol-dipalmitoylphosphatidylserine and dimyristoylphosphatidylcholine-cholesterol-dihexadecylphosphate (4:3:4 molar ratio) provided the best improvement in antimicrobial activity against the various bacterial strains investigated. The liposome formulation produced higher intracellular fluoroquinolone concentrations than those achieved simultaneously with the free drug in both E. coli and P. aeruginosa.Since the discovery of the original DNA gyrase inhibitor nalidixic acid, numerous structural modifications have been carried out to the quinolone nucleus to increase antimicrobial activity and improve pharmacokinetic performance (12,22,29,46).The efficacy of fluoroquinolone antibiotics has led to their proposed use for the treatment and prophylaxis of different bacterial diseases: therapy for the respiratory tract, skin structure, and bone and gastrointestinal infections, as well as urinary tract infections (20,21,23,36,41). However, many studies were developed to improve the potency and spectrum, to achieve sustained blood levels, and to reduce as much as possible drug interactions with various metabolic pathways and physiological processes. Particularly, the use of antibiotic "carrier/delivery systems" would result in enhanced concentrations of the antimicrobial agent at the site of infection. In fact, delivery systems can contribute to (i) targeting of the drug to the infected tissues, (ii) increasing intracellular antibiotic concentrations, and (iii) reducing toxicity of potentially toxic drugs resulting from the targeting to the infectious organisms.Liposomes are possible carriers for controlled drug delivery and targeting by the intravenous route. As with most drug carriers, liposomes have been extensively used in an attempt to improve the selective delivery and the therapeutic index of antimicrobial agents (3, 47). Liposomes, artificial phospholipid membranes, are usually produced from naturally occurring, biodegradable, and nontoxic lipids, such as lecithin, cholesterol, and phosphatidylserine.The aim of the study described here was to investigate the antimicrobial activity against and accumulation in bacteria of ofloxacin-loaded liposomes (of different lipid compositions) in comparison to those of free drugs. Our preliminary experi...

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Formulation parameters of fluoroquinolone-loaded liposomes and in vitro antimicrobial activity

Cited by 41 publications

References 21 publications

A comparison of the in vitro antimicrobial activity of liposomes containing meropenem and gentamicin

A comparison of the in vitro antimicrobial activity of liposomes containing meropenem and gentamicin

Preparation and Evaluation of Thermosensitive Liposomal Hydrogel for Enhanced Transcorneal Permeation of Ofloxacin

Ofloxacin-Loaded Liposomes: In Vitro Activity and Drug Accumulation in Bacteria

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