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AssigneesSeed Co., Ltd., Senju Pharmaceutical Co., Ltd.
InventorsTakao Sato, Toru Matsunaga, Aya Ichinokawa, Osamu Sakai
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Disclosed is a sustainedly drug-releasing hydrogel contact lens which can sustainedly release an anionic medicament such as an allergy-treating agent in a mildly irritating and effective manner while achieving vision correction. Specifically disclosed is a hydrogel comprising ionic monomers composed of at least a cationic monomer and an anionic monomer, wherein the component ratio of the ionic monomers is 5 to 20 mol % inclusive relative to the total amount of monomers that constitute the gel, and the content of the anionic monomer is 15 to 25 mol % inclusive relative to the content of the cationic monomer.
A daily disposable hydrogel contact lens for sustained drug release of sustainedly releasing a dose of an anionic drug, wherein the amount of initial release in a time period of about 4 hours after the start of wearing the hydrogel contact lens is not more than 50% of the dose of the anionic drug contained in the hydrogel contact lens, and not less than 80% of the dose of the anionic drug contained in the hydrogel contact lens is released at least in 14 hours after the start of wearing the hydrogel contact lens;
Dependencies are inferred from the claim text.
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Lenses: contact lenses
Galenical forms characterised by the site of application: eye, e.g. artificial tears
Eye, e.g. artificial tears: ocular inserts or implants
Drugs for disorders of the senses: ophthalmic agents
About 3 years 8 months of term left · ends 13 Jun 2030 (estimated)
The present invention relates to a hydrogel contact lens for sustained drug release and a drug release method using the hydrogel contact lenses for sustained drug release. More particularly, the present invention relates to a hydrogel contact lens for sustained drug release that can suitably be used as a daily disposable contact lens that can release an anionic ophthalmic drug effectively in a relatively short period of time and a drug release method using the contact lens. As cross reference to other applications, the present application claims a benefit of priority from Japanese Patent Application No. 2009-037862, filed on Feb. 20, 2009, the entire contents of which are incorporated herein by reference.
The number of contact lens wearers has reached to 16 millions and contact lenses have been widely acknowledged as one of the most popular types of medical equipment. Hydrogel contact lenses take 70% or more of the contact lens market and daily-disposable-typed hydrogel contact lenses have the largest share among hydrogel contact lenses. Generally, daily-disposable-typed hydrogel contact lens wearers can wear contact lenses for 18 hours a day at longest.
Ophthalmic disorders include glaucoma, various infectious diseases and allergies. Particularly, seasonal eye allergies, pollen allergy in particular, are widely observed in daily lives and there is a large demand for easy and effective therapies against the eye allergies. Sodium cromoglycate in the form of eye-drops has been popularly used as a drug for treating eye allergies but, this drug is irritating to eyes when administered so that the drug needs to be used to alleviate the irritating side effect of the drug by adding a refreshing agent, a mucopolysaccharide and the like to the drug (see JP 2004-59583 A and JP 2005-187407 A, the disclosures of which are incorporated herein by reference).
FIG. 1 is a graph showing the release ratio of sodium cromoglycate in an eye.
The inventors of the present invention achieved this invention after examining various possible methods for releasing an appropriate amount of an anionic drug to be used as allergy therapy in an appropriate release time as well as minimizing the irritation to eyes.
Firstly, the inventors of the present invention examined various methods for controlling the amount of initial release of each of a variety of anionic drugs including sodium cromoglycate that can be used to relieve allergies such as pollen allergy but are irritating to eyes.
Normally, in the process of releasing an anionic drug from a contact lens, the drug contained at and near the surface of the contact lens is quickly released into lacrimal fluid and subsequently the anionic drug that is interacting with the cationic group in the lens material is isolated by an ion exchange reaction with the negative ion component in lacrimal fluid so that the drug is released in a sustained manner. The time of sustained release and the quantity that is released during that time vary as a function of the behavior of the contained drug in the lens but can be controlled by the crosslink density of the material.