Chemistry: molecular biology and microbiology – Process of utilizing an enzyme or micro-organism to destroy... – Cleaning using a micro-organism or enzyme
Reexamination Certificate
1998-12-03
2001-07-10
Beisner, William H. (Department: 1744)
Chemistry: molecular biology and microbiology
Process of utilizing an enzyme or micro-organism to destroy...
Cleaning using a micro-organism or enzyme
C422S037000, C510S114000, C514S840000, C134S901000
Reexamination Certificate
active
06258591
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a one-solution type of combined formulation for disinfecting, neutralizing and cleaning contact lenses and a method of caring for contact lenses using the same. More specifically, it relates to a one-solution type of combinated formulation suitable for disinfecting, neutralizing and cleaning soiled contact lenses quickly and simply, and a method for caring for a contact lenses using the same.
PRIOR ART
Methods that have been currently used for disinfecting soft contact lenses are roughly divided into disinfection by boiling and disinfection by chemicals. Although disinfection by boiling is substantially effective for the disinfection of all kinds of microorganisms such as bacteria, viruses and molds, it may cause a lens to become white turbidity due to the denaturation and coagulation of protein or other substances adhering to a soft contact lens by heat or the deformation and discoloration of a lens by long-term repeated heating. This method has such inconvenience that it cannot be used without a power source.
A large number of methods for disinfection by chemicals have been also known, and some of 3% hydrogen peroxide and biguanide-based antiseptic solutions have a low sterilizing effect according to types of microorganisms. When misused, they act as an excessively strong irritant to the cornea epithelium and conjunctiva and may cause a disorder of the cornea.
Of various halogen-based disinfectants, iodine-based disinfectants are excellent chemical disinfectants in terms of sterilizing effect and safety to eyes. Examples of disinfection using these iodine-based disinfectants are described in the specification of UK Patent No. 1,604,020, the specification of U.S. Pat. No. 4,312,833, Contacto, pp. 33 to 37 (1975), the Bulletin No. 23 of the Japan Contact Lens Society, pp. 150 to 154 (1981) and the Bulletin No. 20 of the Japan Contact Lens Society, pp. 96 to 101 (1978). However, in these methods, the removal and neutralization of the residual disinfectant after disinfection using an iodine-based disinfectant are carried out by the self-sublimation of iodine or using a weak reducer. Therefore, the removal of active iodine takes a long time and the neutralization may be incomplete. As a result, a soft contact lens may be changed color as the iodine agent is adsorbed to the matrix of the lens and may be deformed or deteriorated by the reaction between iodine and the lens material.
Further, though the iodine formulation is relatively safe to eyes, when it is adsorbed and accumulated in a lens without being completely neutralized, an iodine-based chemical is gradually released while the lens is worn and may inflame the eyes of an allergic person or cause a disorder of the cornea, as described in Annals Ophthalmology, pp. 361 to 364 (1981). WO 96/00590 and WO 96/00591 disclose a method for disinfecting contact lens and subsequent reduction, wherein the lens are contacted with a solution combinated with a reducing solution and an excess amount of iodine formulation than the required amount for oxidizing a contained reducer, and further a reducer is added to reduce the residual iodine formulation. In addition, of cares of a soft contact lens, it is important to remove protein or lipid adhering to a lens, and a cleaning agent is required for this purpose. However, there has not been yet known a one-solution type of combinated formulation comprising an iodine disinfectant, neutralizer, proteolytic enzyme and surfactant.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a one-solution type of combinated formulation for carrying out disinfection, neutralization and cleaning in one solution.
It is another object of the present invention to provide a one-solution type of combinated formulation suitable for disinfecting, neutralizing and cleaning a soiled contact lens quickly and easily.
It is still another object of the present invention to provide a one-solution type of combinated formulation for disinfecting, neutralizing and cleaning a soft contact lens easily, which comprises not only of an iodine disinfectant exhibiting a strong sterilizing effect but also relatively high safety to improve the defect of a formulation using a neutralization method of the prior art by combinating two other formulations.
It is still another object of the present invention to provide a method for cleaning a soiled contact lens quickly and easily using the one-solution type of combinated formulation of the present invention.
Other objects and advantages of the present invention will become apparent from the following description.
According to the present invention, firstly, the above objects and advantages of the present invention can be attained by a one-solution type of combinated formulation for disinfecting, neutralizing and cleaning a contact lens, which comprises (A) the first formulation containing an iodine-based disinfectant and a proteolytic enzyme and (B) the second formulation containing a reducer and a foaming agent and having a delayed release coating, and containing a nonionic surfactant in at least one of the first and second formulations.
The one-solution type of combinated formulation of the present invention comprises the first formulation (A) and the second formulation (B) at least one of which contains a nonionic surfactant.
The first formulation contains an iodine-based disinfectant and a proteolytic enzyme, and a nonionic surfactant as the case may be.
The iodine-based disinfectant advantageously used in the present invention is conventionally well-known as povidone iodine or polyvinly alcohol iodine wherein iodine molecules (I
2
) are included in macromolecule such as polyvinyl pyrrolidone (PVP) or polyvinyl alcohol (PVA). These macromolecule-coupled iodine agents are extremely excellent disinfectants which (1) are water-soluble, (2) stabilize subliming and unstable iodine molecules in a solid state, and (3) reduce toxicity, as compared with free iodine agents, and which have strong bactericidal action equal to that of free iodine agents. Namely, the disinfectants have a wide range of antibacterial spectra against bacteria, antibiotic resistant germs, molds, viruses and the like.
The proteolytic enzyme advantageously used in the present invention must retain sufficient cleaning power for a lens soiled with protein in the presence of the iodine disinfectant which is a strong oxidant. Since a sulfur group, that is, particularly sulfur atoms such as a thiol group or dithio group, are readily oxidized by an iodine compound, the activity of enzymes having a large number of these sulfur groups, such as papain, bromelain, ficin, pancreatin and cathepsin is greatly reduced by the presence of the iodine disinfectants. Therefore, they cannot be recommended as a preferred enzyme cleaning agent in the present invention.
Experiments have been conducted on stability using various enzymes under the presence of the iodine formulation. As a result, it has been found that proteolytic enzymes produced by bacillus bacteria and enzymes derived from animal pancreases are relatively stable.
Proteolytic enzymes available on the market include Bioprase, Biotamilase (of Nagase Biochemicals Ltd.), Protease N “Amano” (of Amano Pharmaceutical Co., Ltd.), Subtilisin A, Alcarase, Esperase, Trypsin, Chymotrypsin (of Novo Nordisk Bioindustry Ltd.) and the like. A suitable one is selected out of these.
The first formulation contains an iodine-based disinfectant preferably in an amount of 0.01 to 50 wt %, more preferably 0.1 to 15 wt %, based on the first formulation. When the first formulation is dissolved in an aqueous solution as the combinated formulation of the present invention, the iodine-based disinfectant is contained in the aqueous solution preferably in an amount of 1 to 5,000 ppm, more preferably 10 to 1,500 ppm in terms of the concentration of effective iodine. If the concentration is less than 1 ppm, the disinfecting power of the disinfectant will lower. On the other hand, if the concentration is more than 5,000 ppm, the disinfec
Fujii Takashi
Morita Mika
Nakamura Shigeru
Ohnuma Takeshi
Tanouchi Hiroshi
Beisner William H.
Ophtecs Corporation
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