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I saw that Visine Intensive--maybe only available in Europe--uses "Tamarind Gum" in its formulation. Found something about that this morning...while waiting for an airport shuttle:
http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_DocSum
Development of a simple dry eye model in the albino rabbit and evaluation of some tear substitutes.Burgalassi S, Panichi L, Chetoni P, Saettone MF, Boldrini E.
Department of Pharmaceutical Sciences, University of Pisa, Pisa, Italy. burgal@farm.unipi.it
The present paper is concerned with the development of a simple dry eye model in the rabbit, induced by daily repeated instillations of 1.0% atropine sulphate. The evolution of the dry eye syndrome in the animals was assessed by the Schirmer I test and by examination of the cornea after fluorescein staining. The model produced rapidly some typical dry eye symptoms and could be satisfactorily used for a preliminary assessment of the protective activity of some polymeric tear substitutes. These were based on hydroxypropylmethylcellulose, sodium hyaluronate, sodium polyacrylate or tamarind gum. The latter polymer showed the best overall results. Ferning tests on the formulations were also performed: their validity as predictors of the efficacy of tear substitutes is discussed.
PMID: 10224507 [PubMed - indexed for MEDLINE]
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Note how they INDUCED dry eye into rabbits: using Atropine, likely preserved with BAK. Worked for me
More info:
http://jac.oxfordjournals.org/cgi/content/full/46/5/831
This report describes the efficacy of a novel mucoadhesive polymer, the tamarind seed polysaccharide, as a delivery system for the ocular administration of hydrophilic and hydrophobic antibiotics. Healthy rabbits were subjected to repeated ocular instillations with either conventional gentamicin or ofloxacin or these agents viscosified with the tamarind seed polysaccharide. Administration of viscosified preparations produced antibiotic concentrations both in the aqueous humour and cornea that were significantly higher than those achieved with the drugs alone. The increased drug absorption and the prolonged drug elimination phase obtained with the viscosified formulations indicate the usefulness of the tamarind seed polysaccharide as an ophthalmic delivery system for topical administration of antibiotics
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Quite likely, the idea here is to increase the permeability of a drug into and through the eye, AND to increase the amount of time the drug stays "resident" (lingers, allowing it to do its job).
Keep the faith!
Neil
http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_DocSum
Development of a simple dry eye model in the albino rabbit and evaluation of some tear substitutes.Burgalassi S, Panichi L, Chetoni P, Saettone MF, Boldrini E.
Department of Pharmaceutical Sciences, University of Pisa, Pisa, Italy. burgal@farm.unipi.it
The present paper is concerned with the development of a simple dry eye model in the rabbit, induced by daily repeated instillations of 1.0% atropine sulphate. The evolution of the dry eye syndrome in the animals was assessed by the Schirmer I test and by examination of the cornea after fluorescein staining. The model produced rapidly some typical dry eye symptoms and could be satisfactorily used for a preliminary assessment of the protective activity of some polymeric tear substitutes. These were based on hydroxypropylmethylcellulose, sodium hyaluronate, sodium polyacrylate or tamarind gum. The latter polymer showed the best overall results. Ferning tests on the formulations were also performed: their validity as predictors of the efficacy of tear substitutes is discussed.
PMID: 10224507 [PubMed - indexed for MEDLINE]
--
Note how they INDUCED dry eye into rabbits: using Atropine, likely preserved with BAK. Worked for me
More info:
http://jac.oxfordjournals.org/cgi/content/full/46/5/831
This report describes the efficacy of a novel mucoadhesive polymer, the tamarind seed polysaccharide, as a delivery system for the ocular administration of hydrophilic and hydrophobic antibiotics. Healthy rabbits were subjected to repeated ocular instillations with either conventional gentamicin or ofloxacin or these agents viscosified with the tamarind seed polysaccharide. Administration of viscosified preparations produced antibiotic concentrations both in the aqueous humour and cornea that were significantly higher than those achieved with the drugs alone. The increased drug absorption and the prolonged drug elimination phase obtained with the viscosified formulations indicate the usefulness of the tamarind seed polysaccharide as an ophthalmic delivery system for topical administration of antibiotics
--
Quite likely, the idea here is to increase the permeability of a drug into and through the eye, AND to increase the amount of time the drug stays "resident" (lingers, allowing it to do its job).
Keep the faith!
Neil