Gel-forming erodible inserts for ocular controlled delivery of ofloxacin

Colo, Giacomo Di; Burgalassi, Susi; Chetoni, Patrizia; Fiaschi, Matteo; Zambito, Ylenia; Saettone, M. F.

doi:10.1016/s0378-5173(00)00671-2

Cited by 76 publications

(43 citation statements)

References 15 publications

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“…22) Although Wang et al 23) reported that cationized gelatin with ethylenediamine enhanced the absorption of FD-4 after nasal administration, its enhancing potency were lower than that of PLA, 24) suggesting that amount of positive charge in a molecule may have a significance for the enhancing potency of polycations because there is a significant difference in number of amine residue between PLA and ethylenediaminated gelatin with comparable molecular weight. Thus, PLA appears to have the ability to increase drug absorption into the aqueous humor in a manner similar to that of those enhancers.…”

Section: Discussionmentioning

confidence: 99%

Ability of Poly-<small>L</small>-arginine to Enhance Drug Absorption into Aqueous Humor and Vitreous Body after Instillation in Rabbits

Nemoto

Ueda

Akimoto

et al. 2007

Biological & Pharmaceutical Bulletin

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Section: Discussionmentioning

confidence: 99%

Ability of Poly-<small>L</small>-arginine to Enhance Drug Absorption into Aqueous Humor and Vitreous Body after Instillation in Rabbits

Nemoto

Ueda

Akimoto

et al. 2007

Biological & Pharmaceutical Bulletin

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“…Each formulation was tested on three albino rabbits; the experiment was performed by a single instillation (50 μl) of the niosomal preparation under test into the conjunctival sac of one eye, whilst the contralateral eye served as control. Both eyes of the rabbits under test were examined for any irritation signs, such as conjunctival: corneal edema and/or hyperemia on the basis of direct visual observation using a slit lamp, before treatment, and 1, 24 and 48 h after instillation (31,32). The animal experiments were conducted in full compliance with local, national, ethical and regulatory principles for animal care and was approved by the Cairo University Animal Care Committee…”

Section: Ocular Irritancy Test Of Niosome-encapsulated Gentamicinmentioning

confidence: 99%

Niosome-Encapsulated Gentamicin for Ophthalmic Controlled Delivery

2008

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Abstract. The objective of the present research was to investigate the feasibility of using non-ionic surfactant vesicles (niosomes) as carriers for the ophthalmic controlled delivery of a water soluble local antibiotic; gentamicin sulphate. Niosomal formulations were prepared using various surfactants (Tween 60, Tween 80 or Brij 35), in the presence of cholesterol and a negative charge inducer dicetyl phosphate (DCP) in different molar ratios and by employing a thin film hydration technique. The ability of these vesicles to entrap the studied drug was evaluated by determining the entrapment efficiency %EE after centrifugation and separation of the formed vesicles. Photomicroscopy and transmission electron microscopy as well as particle size analysis were used to study the formation, morphology and size of the drug loaded niosomes. Results showed a substantial change in the release rate and an alteration in the %EE of gentamicin sulphate from niosomal formulations upon varying type of surfactant, cholesterol content and presence or absence of DCP. In-vitro drug release results confirmed that niosomal formulations have exhibited a high retention of gentamicin sulphate inside the vesicles such that their in vitro release was slower compared to the drug solution. A preparation with 1:1:0.1 molar ratio of Tween 60, cholesterol and DCP gave the most advantageous entrapment (92.02%±1.43) and release results (Q 8h =66.29%±1.33) as compared to other compositions. Ocular irritancy test performed on albino rabbits, showed no sign of irritation for all tested niosomal formulations.

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“…Ntrimethyl chitosan (TMC) was synthesized from ChS as described by Di Colo et al [7]. N-carboxymethyl chitosan (CMCh) was synthesized from ChC as described by Di Colo et al [8]. DMS (water solubility, 0.1 mg/ml [9]) was obtained as microparticles (<1.3 μm) by spray-drying a 0.09 mg/ml solution (Mini Spray Drier BÜCHI B-191, inlet and outlet temperature, 150°C and 60°C, respectively; spray nozzle, 0.7 mm; feed flow, 8 ml/min).…”

Section: Methodsmentioning

confidence: 99%

A Novel Polyelectrolyte Complex (PEC) Hydrogel for Controlled Drug Delivery to the Distal Intestine

Zaino¹,

Zambito²,

Mollica³

et al. 2007

TODDJ

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This work was aimed at preparing and evaluating a physically crosslinked hydrogel for the controlled release of diverse drugs to the distal intestine. A solution of fluorescein isothiocyanate dextran, MW 4400 Da (FD4), or a dispersion of micronized dexamethasone (DMS) was microencapsulated into a PEC hydrogel, composed of polycationic N-trimethyl chitosan (TMC) and polyanionic N-carboxymethyl chitosan (CMCh). A fine spray of a 1% CMCh solution containing 1% FD4 in solution or 0.1% DMS in dispersion was directed into a 2% TMC solution, then the resulting microcapsules (MCPS) were lyophilized. MCPS were analyzed by SEM and solid-state NMR. Drug release from MCPS was too fast, so these were compressed into matrices (weight 20 mg; diameter 6 mm; drug load 2.5%, with FD4, or 3.7%, with DMS) which were enteric coated. Drug release from matrices was studied simulating matrix transit across GI environments of different pHs, from stomach to proximal colon. The enteric film hindered release in stomach and proximal small intestine. After film dissolution at ileum pH, release occurred with a pattern described by the Peppas equation (n=0.6, with DMS; n=0.7, with FD4). As the pH changed from 7.4 to 6 (from ileum to ascending colon) MCPS were liberated from matrix surface. This phenomenon sustained the release rate. The present MCPS allow controlled doses of macromolecular or microparticulate drugs being uniformly loaded into controlled-release matrices based on a physically crosslinked, biodegradable hydrogel.

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Gel-forming erodible inserts for ocular controlled delivery of ofloxacin

Cited by 76 publications

References 15 publications

Ability of Poly-<small>L</small>-arginine to Enhance Drug Absorption into Aqueous Humor and Vitreous Body after Instillation in Rabbits

Ability of Poly-<small>L</small>-arginine to Enhance Drug Absorption into Aqueous Humor and Vitreous Body after Instillation in Rabbits

Niosome-Encapsulated Gentamicin for Ophthalmic Controlled Delivery

A Novel Polyelectrolyte Complex (PEC) Hydrogel for Controlled Drug Delivery to the Distal Intestine

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