Ocular drug delivery in veterinary medicine

Baeyens, Vincent; Percicot, Christine L.; Zignani, M.; Deshpande, Arati; Kaltsatos, V.; Gurny, Robert

doi:10.1016/s0169-409x(97)00088-4

Cited by 40 publications

(11 citation statements)

References 173 publications

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“…between 4-5 o C at a concentration range of 20-30% w/w, while converting into a gel upon increasing the temperature of the medium. P407 is a non-ionic polymer (polyoxyethylenepolyoxypropylene-polyoxyethylene; PEOn-PPOn-PEOn), consisting of a central hydrophobic block of polypropylene glycol in addition to hydrophilic blocks of polyoxyethylene (Baeyens et al, 1997). P407 has been widely used in nasal , ophthalmic (Hao et al, 2014), vaginal (Rossi et al, 2014), and topical (Heilmann et al, 2013) formulations.…”

Section: Introductionmentioning

confidence: 99%

Poloxamer-based thermoresponsive ketorolac tromethamine in situ gel preparations: Design, characterisation, toxicity and transcorneal permeation studies

Fathalla

Vangala

Longman

et al. 2017

European Journal of Pharmaceutics and Biopharmaceutics

143

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, Poloxamer-based thermoresponsive ketorolac tromethamine in situ gel preparations: Design, characterisation, toxicity and transcorneal permeation studies, European Journal of Pharmaceutics and Biopharmaceutics (2017), doi: http://dx.doi.org/10. 1016/j.ejpb.2017.01.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThis study was aimed at preparing, characterising and evaluating in situ gel formulations based on a blend of two hydrophilic polymers i.e. poloxamer 407 (P407) and poloxamer 188 (P188) for a sustained ocular delivery of ketorolac tromethamine (KT). Drug-polymer interaction studies were performed using DSC and FT-IR. The gelation temperature (T sol-gel ), gelation time, rheological behaviour, mucoadhesive characteristics of these gels, transcorneal permeation and ocular irritation as well as toxicity was investigated. DSC and FT-IR studies revealed that there may be electrostatic interactions between the drug and the polymers used.P188 modified the T sol/gel of P407 bringing it close to eye temperature (35 o C) compared with the formulation containing P407 alone. Moreover, gels that comprised P407 and P188 exhibited a pseudoplastic behaviour at different concentrations. Furthermore, mucoadhesion study using mucin discs showed that in situ gel formulations have good mucoadhesive characteristics upon increasing the concentration of P407. When comparing formulations PP11 and PP12, the work of adhesion decreased significantly (P < 0.001) from 377.9 ± 7.79 mN.mm to 272.3 ± 6.11 mN.mm. In vitro release and ex vivo permeation experiments indicated that the in situ gels were able to prolong and control KT release as only 48% of the KT released within 12 h. In addition, the HET-CAM and BCOP tests confirmed the nonirritancy of KT loaded in situ gels, and HET-CAM test demonstrated the ability of ocular protection against strongly irritant substances. MTT assay on primary corneal epithelial cells revealed that in situ gel formulations loaded with KT showed reasonable and acceptable percent cell viability compared with control samples.

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Section: Introductionmentioning

confidence: 99%

Poloxamer-based thermoresponsive ketorolac tromethamine in situ gel preparations: Design, characterisation, toxicity and transcorneal permeation studies

Fathalla

Vangala

Longman

et al. 2017

European Journal of Pharmaceutics and Biopharmaceutics

143

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“…, 2005), but variation in individual tolerance, the need for trained personnel for application and problems during insertion with possible expulsion are practical limits (Kaufman et al. , 1994; Baeyens et al. , 1997).…”

Section: Discussionmentioning

confidence: 99%

“…Externally applied implant systems (biodegradable or not) give a release of medication from 2 weeks to several months. Soluble or bioadhesive ophthalmologic drug inserts and collagen films are examples of this technique already investigated in dogs and rabbits (Gurtler et al, 1995;Baeyens et al, 1998;Patel et al, 2005), but variation in individual tolerance, the need for trained personnel for application and problems during insertion with possible expulsion are practical limits (Kaufman et al, 1994;Baeyens et al, 1997). Finally, the use of precursor drugs (esters or di-esters), which change upon ocular contact from inactive to active component is another alternative but until now the chemical stability of these drugs in hydrophilic solutions is a major problem (Patel et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of thein vivobehaviour of gentamicin sulphate ocular mini‐tablets in ponies

Gasthuys

Pockelé

Vervaet

et al. 2007

Vet Pharm & Therapeutics

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The in vivo behaviour of 5% gentamicin sulphate ocular mini-tablets (2-mm diameter, 6.525 mg weight) was compared with gentamicin eye drops in six ponies. Two mini-tablets were inserted on the bulbar conjunctiva of the right eye while a similar dose of gentamicin was administered via eye drops in the left eye. Irritation induced by the mini-tablets and the eye drops was evaluated using a visual analogue scale (0-10). Tears were sampled with ophthalmologic absorption triangles for 1 min for the determination of the concentration of gentamicin sulphate using a microbiological plate diffusion method. Irritation induced by the tablets was minor and clinically acceptable (overall median score of 1.7 +/- 1.4). Eye drops induced a sharp increase in gentamicin sulphate concentration (364.4 microg/mL after 5 min) followed by a fast decline (10.8 microg/mL after 60 min). The increase in concentration induced by the ocular mini-tablets was less pronounced (up to 56.2 microg/mL after 30 min) and followed by a gradual decrease; the concentration remained above 15 microg/mL for 8 h. Ocular 5% gentamicin sulphate mini-tablets are clinically well-tolerated in ponies, assuring a constant concentration in the tears for at least 8 h.

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“…Mandel et al were the first to formally introduce the concept of pro-drugs in the late 1970s with the testing of dipinefrin (a pro-drug of epinephrine) for improvement of corneal penetration of epinephrine. Since then, several other ocular drugs have been studied for prodrug derivatization (23). In order to avoid the nonspecific absorption of drugs into nontargeted tissues and to avoid systemic toxicity, intravitreal administration of pro-drugs may be justified.…”

Section: Injectable Pro-drugsmentioning

confidence: 99%

New Techniques for Drug Delivery to the Posterior Eye Segment

2010

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Ocular drug delivery has become an increasingly important field of research especially when treating posterior segment diseases of the eye, such as age-related macular degeneration, diabetic retinopathy, posterior uveitis and retinitis. These diseases are the leading causes of vision loss in developed countries which require repeated long-term administration of therapeutic agents. New drugs for the medication of the posterior ocular segment have emerged, but most drugs are delivered by repeated intravitreal injections associated with ocular complications. Advances in ocular drug delivery system research are expected to provide new tools for the treatment of the posterior segment diseases, providing improved drug penetration, prolonged action, higher efficacy, improved safety and less invasive administration, resulting in higher patient compliance. This review provides an insight into the recent progress and trends in ocular drug delivery systems for treating posterior eye segment diseases, with an emphasis on transscleral iontophoresis.

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Ocular drug delivery in veterinary medicine

Cited by 40 publications

References 173 publications

Poloxamer-based thermoresponsive ketorolac tromethamine in situ gel preparations: Design, characterisation, toxicity and transcorneal permeation studies

Poloxamer-based thermoresponsive ketorolac tromethamine in situ gel preparations: Design, characterisation, toxicity and transcorneal permeation studies

Evaluation of thein vivobehaviour of gentamicin sulphate ocular mini‐tablets in ponies

New Techniques for Drug Delivery to the Posterior Eye Segment

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