Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L12/00—Methods or apparatus for disinfecting or sterilising contact lenses; Accessories therefor
  • A61L12/08—Methods or apparatus for disinfecting or sterilising contact lenses; Accessories therefor using chemical substances
  • A61L12/12—Non-macromolecular oxygen-containing compounds, e.g. hydrogen peroxide or ozone
  • A61L12/124—Hydrogen peroxide; Peroxy compounds
  • A61L12/128—Hydrogen peroxide; Peroxy compounds neutralised with catalysts

Definitions

• This invention relates generally to the preservation or inhibition of microbial growth in aqueous streams in a health care manufacturing operation.
• this invention relates to preservation of streams in pharmaceutical or ophthalmic production facilities, such as contact lens production facilities.
• Manufacturing facilities which produce health care products are under ethical and legal requirements to maintain exceptionally clean production facilities.
• contact lens manufacturing facilities are subject to strict cleanliness protocols in order to ensure consumer safety.
• manufacturing facilities focus on using highly pure raw materials and avoiding introduction of microorganisms during the storage or manufacturing processes.
• aqueous environments such as process flowpipes, present a problem because of the enhanced likelihood of bacteria growing in any moist, dark environment.
• a method of preserving aqueous flow streams in health care production facilities is desirable, in order to inhibit growth of any microorganisms which inadvertently contaminate aqueous raw material streams.
• many of these antimicrobials and preservatives cannot remain in a final health care product because of the incompatibility with human tissue.
• benzalconium chloride (BAK or BAC) has been used as an antimicrobial in ophthalmic drug products and lens care disinfection products.
• BAK benzalconium chloride
• BAK causes stinging and redness in many patients when contacted with the eye.
• BAK is incompatible with some drugs.
• compositions and processes which preserve and/or disinfect production flow streams without resulting in products which cause discomfort when used or incompatibility with other components of the product.
• Another object of the invention is to provide methods and devices for removing a peroxide preservative and/or disinfectant from a continuous-flow stream.
• a further object of the invention is to provide a means for in-line decomposition of hydrogen peroxide in a ophthalmic lens production facility.
• An embodiment of the invention is a method of preserving and/or disinfecting a continuous- flow aqueous stream in a health care product manufacturing facility.
• the method involves preserving an aqueous solution with a preservative, providing a continuous flow stream of said preserved solution, and continuously or semi-continuously decomposing substantially all of the preservative in said preserved stream prior to dispensing the aqueous solution.
• a preferred preservative is hydrogen peroxide.
• the catalytic chamber for decomposition of peroxide in a continuous flow conduit.
• the catalytic chamber includes an external housing adapted to be disposed within or as part of a fluid-conveying conduit, and a catalytic element disposed within the housing having catalytic material disposed therein or thereon.
• the catalytic chamber defines openings therethrough to allow passage of fluid. The catalytic chamber forces contact between fluid passing therethrough and the catalytic element, thereby accelerating decomposition of any peroxide present in any fluid passing therethrough.
• FIG. 1 is a side sectional exploded view of an exemplary catalytic chamber of the present invention.
• FIG. 2 is a side sectional view of a tool useful in assembling the catalytic chamber of FIG. 1.
• FIG. 3 is a plan view of a support member for a perforated disk.
• FIG. 4 is a bottom view of a catalytic chamber.
• FIG. 5 illustrates a catalytic element retention means in a cross-sectional view.
• An embodiment of the invention is a method of preserving and/or disinfecting a continuous- flow aqueous stream in a health care product manufacturing facility.
• the method is particularly useful in preserving saline solutions in piping and storage networks within contact lens production facilities, although the scope of the invention is not so limited.
• a particularly useful preservative is a peroxide, preferably hydrogen peroxide or an additive which generates hydrogen peroxide in solution (e.g., sodium perborate).
• the method generally involves the steps of preserving an aqueous solution with a preservative, providing a continuous flow stream of the preserved solution; and continuously or semi-continuously decomposing substantially all of the preservative in said preserved stream prior to dispensing said aqueous solution.
• Another embodiment of the invention is a device for decomposing peroxide in a continuous- flow conduit.
• the decomposition of the peroxide preferably occurs immediately prior to dispensing of the aqueous solution into the product package, in order to minimize any area of piping which is not preserved.
• the decomposition device generally includes an external housing adapted to be disposed within or as part of a fluid-conveying conduit, including inlet and outlet openings and a catalytic element disposed within the housing having catalytic material disposed therein or - 4 -
• the device includes openings therethrough to allow passage of fluid.
• the device forces contact between fluid passing therethrough and the catalytic element, thereby accelerating decomposition of peroxide present in fluid passing therethrough.
• the device for decomposing preservative is termed a "catalytic chamber".
• the catalytic chamber includes an external housing which is adapted to be disposed within or as part of a fluid-conveying conduit and a catalytic element disposed within the external housing.
• the catalytic element may have catalytic material disposed within the element or coated on portions of the element, or both.
• the catalytic chamber has an inlet opening for receiving upstream flow of solution and an outlet opening for allowing solution to pass out of the chamber.
• the design of the catalytic chamber forces contact between the passing fluid and the catalytic element, thereby accelerating decomposition of any peroxide present in the passing fluid.
• One embodiment of the catalytic chamber includes (a) an external housing adapted to be removably affixed to solution-carrying piping, (b) a catalytic element having inlet and outlet openings, (c) a first catalytic element retention means positioned near the inlet opening and (d) a second catalytic element retention means positioned near the outlet opening.
• Catalytic chamber 10 includes an external housing 12 which provides the ultimate support for all other components.
• External housing 12 is adapted to be releasably affixed to piping (not shown) via standard sanitary clamps (not shown) which are releasably secured to inlet and outlet end flanges 14. Further sealing is provided by o-rings 16 imbedded in the flanges.
• the downstream catalyst retention means includes perforated disk 18 held in place by castellated collar 20.
• perforated disk 18 is inserted into external housing 12.
• castellated collar 20 is inserted and threaded via external threading 22 into internal threading 24 of external housing 12.
• Manipulation of castellated collar 20 within external housing 12 is accomplished with an appropriate tool, such as collar key 42 of FIG. 2.
• piston 26 is inserted into external housing 12.
• Two o-rings 28 positioned on the external wall, near each opening of the piston, guide the piston as it is moved into a resting position within external housing 12.
• a catalytic element or catalytic material (not shown) is then placed or poured into the cavity defined by piston 26.
• Perforated disk 30 is subsequently positioned on top of the catalytic element and castellated collar 32 is secured to piston 26 by threaded engagement.
• Piston 26 includes perforations 34 in downstream support member 36 which provides structural support for perforated disk 30 while minimizing resistance to flow.
• external housing 12 includes downstream support member 38 with perforations 40 designed to minimize fluid resistance while providing support for perforated disk 18. All of the perforations are preferably substantially aligned in order to reduce pressure drop.
• FIG. 3 is a plan view of support member 50 which retains a perforated disk in place within the catalytic chamber.
• Support member 50 has a plurality of substantially uniformly spaced, uniformly sized circular openings which allow fluid to pass through the support member.
• a wide variety of designs of a support member could be envisioned (e.g., variations in opening shape, size and spacing) which would provide substantially the same function as the design of FIG. 3, and such designs are within the scope of the present invention.
• the catalytic element which increases the rate of decomposition of preservative may be formed in a wide variety of shapes and sizes.
• a preferred catalytic element includes a plurality of beads of catalytic material having catalytic material disposed thereon.
• Another preferred catalytic element includes a granular mass of catalytic material (e.g. powder form).
• a preferred catalytic material for decomposing peroxide is platinum.
• the platinum may be used in several forms or combinations of forms.
• the platinum may be coated onto metallic, ceramic or polymeric structures (e.g., spheres or beads) disposed within the catalytic element.
• platinum black or a platinum alloy may be used to decompose peroxide.
• one preferred catalyst form is a powdered or granular platinum or platinum-containing material.
• An advantage of a powdered form is a higher surface area per volume, while a disadvantage is that the pressure drop increases and fouling may be more likely.
• the mesh size of the powder can be varied depending on the particular application, powder having a mesh size of less than 400 microns, preferably less than 325 microns has been found to be useful.
• a preferred catalytic material for decomposing peroxide is platinum-coated alumina powder.
• a weight percentage of platinum of about 1 to 10% has been found to be suited to the application. While the mass of catalytic material to be used may depend on several factors, it has been found that a mass of about 250 to 450 grams, preferably about 310 to 350 grams, is useful in streams having a flow rate of about 350 to 700 ml/min.
• the catalytic element may include catalytic particulates having exposed surfaces of platinum or platinum-containing material and inert packing.
• a preferred inert packing material is alumina powder.
• a catalytic element may include about 1 to 10 weight percent catalytic particulates having exposed surfaces of platinum or platinum- containing material and about 99 to 90 weight percent inert packing.
• the powder or bead catalytic material may be formed into a solid element.
• the catalytic element may be a rigid, sintered disc formed by fusing particles having exposed surfaces of platinum or platinum-containing material.
• the catalytic element includes a solid support meshwork defining a plurality of substantially uniform openings therethrough and a coating of platinum or platinum-containing material deposited on said meshwork.
• a means for retaining the catalytic material is needed in the catalytic chamber.
• a preferred location for placement of the catalytic element retention means is adjacent the upstream and downstream ends of the piston, preferably - 7 -
• a suitable catalytic element retention means is a felt material, in particular, a stainless steel felt material.
• the porosity of the felt is determined, in part, by the size of the catalytic powder being retained by the felt and by the effluent particle concentration and size requirements.
• a suitable felt porosity has been determined to be about 1 to 50 microns, preferably about 5 to 20 microns.
• the upstream felt has a 20 micron porosity, while the downstream felt has a 5 micron porosity.
• FIGs. 4 and 5 illustrate a useful design of a catalytic element retention means formed from a felt material.
• the catalytic element retention means may be formed from plastic, glass, stainless steel or other material which may be made suitably porous (e.g., in a felted, knitted or woven manner).
• FIG. 4 shows catalytic element retention means 60 having molded felted material 62 molded into it, with support on both sides by a screen.
• the bottom surface features O-ring 64 which seals against the inner surface of the catalytic chamber body.
• a similar disk is placed into the piston body. In both cases, the disks are topped with the perforated disks of FIG 3 and held in place by castellated collars.
• the external housing, catalytic element housing, and catalytic element retaining means of the catalytic chamber may be composed of a number of rigid materials, but a preferred group of materials are those which are resistant to corrosion in the presence of the process solution (e.g., 50 ppm hydrogen peroxide in saline).
• a preferred group of materials are the stainless steels (e.g., 316 stainless steel) and rigid, machinable polymers such as polyvinylidene fluoride (PVDF).
• Polymers such as polyvinylidene fluoride, are particularly preferred in order to avoid any possible corrosion problems. While stainless steels may be appropriate for some applications, it has been found that polymeric materials are preferred for long term durability in the presence of 40 to 50 ppm hydrogen peroxide.
• Hydrogen peroxide decomposes into water and oxygen under certain conditions. It is known that application of light or heat, or contact with a catalyst such as platinum, will accelerate the decomposition of hydrogen peroxide.
• a catalyst such as platinum
• the catalytic chamber is positioned in the flow stream, such that the aqueous process solution continuously or semi-continuously passes through the catalytic chamber. Locating the catalytic chamber in the flow path forces contact of the peroxide in the solution with catalyst in the chamber, thereby causing accelerated peroxide decomposition.
• the catalytic chamber it is preferred to position the catalytic chamber near the end of the flow stream, quite close to the dispensing end.
• the catalytic chamber is located immediately before the valve which controls dispensing, in order to maximize the length of piping which is preserved.
• the peroxide concentration in the flow stream should be sufficiently high to handle potential microbial burden. However, the concentration should be minimized in order to minimize the cost associated with preservative use and the burden upon the catalytic chamber.
• a preferred concentration of hydrogen peroxide in a flow stream is about 20 to 100 ppm, more preferably about 40 to 60 ppm.
• the peroxide concentration In order to use the solution from the flow stream in an ophthalmic product, the peroxide concentration must be reduced to a level which does not cause any substantial irritation to the consumer. In use as contact lens saline storage solution, the peroxide concentration is preferably reduced to below about 10 ppm, more preferably below about 2 ppm, and, in certain circumstances, below about 0.2 ppm.
• the characteristics of the flow stream may vary substantially, depending on the particular production requirements.
• the flow rate may be about 100 to 1000 ml/minute, and in a preferred embodiment, the flow rate is about 350 to 700 ml/min.
• the inner diameter of the piping may be about 1 to 8 inches, and is preferably about 2 to 6 inches.
• the pressure may be about 5 to 100 psig, and is preferably about 10 to 30 psig.
• the design of the catalytic chamber may vary substantially, depending on the requirements of the particular production needs. Some of the factors which impact the design of the catalytic chamber include a balance of the goals of: 1. minimizing pressure drop across the chamber,
• a preferred catalytic chamber has a cylindrical shape in conformance with production plant piping.
• the exterior structural support for the catalytic chamber is preferably a standard piece of threaded piping.
• a preferred external housing for the catalytic chamber is a straight pipe having external threading on either end and internal dimensions roughly the same as the surrounding piping.
• An exemplary catalytic chamber has a PVDF external housing composed of a nominal four inch diameter cylinder containing a PVDF catalytic piston which retains catalytic elements therein.
• a first catalyst retaining means which is composed of a circular piece of BekiportE> 20 AL3 SS AISI 316L-WNR 1.4404 material (Bekaert Corporation, Marietta, Georgia) fused into a polyethylene ring and equipped with o-rings. This seals against the inner surface of the face of the piston. It is covered with a disk and clamped into place using a castellated collar.
• Both the disk covering the catalyst retaining means and the face of the piston are perforated with a series of large holes which allows saline to flow through the center of the piston.
• the piston is equipped with a double Viton® o-ring seal. Downstream of the piston face is a cavity for retaining catalytic elements therein, formed by the void within the cylinder between the first catalyst retention means and a second catalyst retention means (i.e., another circular piece of Bekipor® material of different porosity [5 AL3 SS AISI 316L-WNR 1.4404]).
• This second catalyst retention disk is held in place in a fashion identical to that of the first.
• the chamber itself is filled with about 310 to 350 grams of -325 mesh platinum on alumina powdered catalyst (Pt 5%) having a surface area in excess of 250 m 2 /g.
• the device is equipped with standard sanitary flanges at both ends.
• the device is advantageous in that it is able to retain the large number of small catalyst particles required to reduce the hydrogen peroxide concentration from the 40 to 50 ppm to - 10 -
• the stream will contain no more than about 50 particles/ml which are equal to or greater than 10 mm, no more than 5 particles equal to or greater than 25 mm, and no more than 1 particle greater than or equal to 50 mm.
• This device allows the addition of hydrogen peroxide as an ingredient in saline without its introduction into the final product.
• the bacteriostatic benefits of hydrogen peroxide can be realized in the saline distribution loop piping and in various intermediate steps in the manufacturing process requiring saline.
• the catalytic chamber then removes the hydrogen peroxide at the final packaging step, resulting in a final product that has benefited from the bacteriostatic effect yet is functionally identical, in ophthalmic compatibility, to product manufactured using saline without hydrogen peroxide.
• the solution may be heated in addition to being exposed to catalytic elements.
• the catalytic chamber is equipped with a heating element, internally and/or externally, in order to accelerate or better control the peroxide decomposition rate.

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• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Chemical & Material Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• Epidemiology (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Apparatus For Disinfection Or Sterilisation (AREA)
• Catalysts (AREA)
• Eyeglasses (AREA)
• Removal Of Specific Substances (AREA)
• Treatment Of Water By Oxidation Or Reduction (AREA)

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• 1999
  • 1999-04-12 AU AU36059/99A patent/AU3605999A/en not_active Abandoned
  • 1999-04-12 JP JP2000543177A patent/JP2002511333A/ja active Pending
  • 1999-04-12 CA CA002326895A patent/CA2326895A1/en not_active Abandoned
  • 1999-04-12 EP EP99917972A patent/EP1071478A1/en not_active Withdrawn
  • 1999-04-12 WO PCT/EP1999/002440 patent/WO1999052567A1/en not_active Application Discontinuation
• 2000
  • 2000-10-02 NO NO20004960A patent/NO20004960D0/no not_active Application Discontinuation

Non-Patent Citations (1)

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