Ocular drug bioavailability from topically applied liposomes

Lee, Vincent H.L.; Urrea, Paul T.; Smith, Ronald E.; Schanzlin, David J.

doi:10.1016/0039-6257(85)90109-2

Cited by 75 publications

(19 citation statements)

References 137 publications

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“…This may be explained by the fact that an electrostatic attraction force occurs between positively charged liposomes and negatively charged corneal membrane; we speculate then that liposomes adsorbed to the corneal surface and transfer their membrane associated drug directly to the corneal epithelial cell membrane, thereby facilitating drug passage across the cornea (54,55). Another reason is due to lower solubility of ofloxacin at pH 7.4; at this pH, ofloxacin presents as unionized form.…”

Section: In Vitro Transcorneal Permeationmentioning

confidence: 98%

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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Section: In Vitro Transcorneal Permeationmentioning

confidence: 98%

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

Hosny

2009

AAPS PharmSciTech

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“…This may explained by the fact that an electrostatic attraction force occur between positively charged liposomes and negatively charge corneal membrane. We speculate then that liposomes, adsorbed to the corneal surface, transfer their membrane-associated drug directly to the corneal epithelial cell membranes, thereby facilitating drug transport across the cornea (41,42). Other mechanisms such as endocytosis of liposomes or fusion of liposome membrane with the plasmalemma are also involved in enhanced transport (43).…”

Section: In Vitro Drug Transcorneal Permeationmentioning

confidence: 99%

Ciprofloxacin as Ocular Liposomal Hydrogel

Hosny

2010

AAPS PharmSciTech

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Abstract. The purpose of this study was to prepare and characterize an ocular effective prolonged-release liposomal hydrogel formulation containing ciprofloxacin. Reverse-phase evaporation was used for preparation of liposomes consisting of soybean phosphatidylcholine (PC) and cholesterol (CH). The effect of PC/CH molar ratio on the percentage drug encapsulation was investigated. The effect of additives such as stearylamine (SA) or dicetyl phosphate (DP) as positive and negative charge inducers, respectively, were studied. Morphology, mean size, encapsulation efficiency, and in vitro release of ciprofloxacin from liposomes were evaluated. For hydrogel preparation, Carbopol 940 was applied. In vitro transcorneal permeation through excised albino rabbit cornea was also determined. Optimal encapsulation efficiency of 73.04±3.06% was obtained from liposomes formulated with PC/CH at molar ratio of 5:3 and by increasing CH content above this limit, the encapsulation decreased. Positively charged liposomes showed superior entrapment efficiency (82.01±0.52) over the negatively charged and the neutral liposomes. Hydrogel containing liposomes with lipid content PC, CH, and SA in molar ratio 5:3:1, respectively, showed the best release and transcorneal permeation with the percentage permeation of 30.6%. These results suggest that the degree of encapsulation of ciprofloxacin into liposomes and prolonged in vitro release depend on composition of the vesicles. In addition, the polymer hydrogel used in preparation ensure steady and prolonged transcorneal permeation. In conclusion, ciprofloxacin liposomal hydrogel is a suitable delivery system for improving the ocular bioavailability of ciprofloxacin.

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“…Additionally, the requirement of prolonged sustained drug delivery also warrants manipulations of the liposome characteristics. Efficacy of liposomes as a drug carrier depends upon various factors such as charge, size, lipid composition of the liposomal membrane, stability and corneal residence time (Lee et al, 1985).…”

Section: Conventional Liposomes: Modifications To Meet the Challengesmentioning

confidence: 99%

Liposomes in topical ophthalmic drug delivery: an update

et al. 2014

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Topical route of administration is the most commonly used method for the treatment of ophthalmic diseases. However, presence of several layers of permeation barriers starting from the tear film till the inner layers of cornea make it difficult to achieve the therapeutic concentrations in the target tissue within the eye. In order to circumvent these barriers and to provide sustained and targeted drug delivery, tremendous advances have been made in developing efficient and safe drug delivery systems. Liposomes due to their unique structure prove to be extremely beneficial drug carriers as they can entrap both the hydrophilic and hydrophobic drugs. The conventional liposomes had several drawbacks particularly their tendency to aggregate, the instability and leakage of entrapped drug and susceptibility to phagocytosis. Due to this reason, for a long time, liposomes as drug delivery systems did not attract much attention of researchers and clinicians. However, over recent years development of new generation liposomes has opened up new approaches for targeted and sustained drug delivery using liposomes and has rejuvenated the interest of researchers in this field. In this review we present a summary of current literature to understand the anatomical and physiological limitation in achieving adequate ocular bioavailability of topically applied drugs and utility of liposomes in overcoming these limitations. The recent developments related to new generation liposomes are discussed.

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Ocular drug bioavailability from topically applied liposomes

Cited by 75 publications

References 137 publications

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

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

Ciprofloxacin as Ocular Liposomal Hydrogel

Liposomes in topical ophthalmic drug delivery: an update

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