GB2439059A

GB2439059A - Sterile wipe package

Info

Publication number: GB2439059A
Application number: GB0611595A
Authority: GB
Inventors: Andrew Philpotts; Neal Wesley; Christopher Graham
Original assignee: AGMA Ltd
Current assignee: AGMA Ltd
Priority date: 2006-06-12
Filing date: 2006-06-12
Publication date: 2007-12-19
Also published as: GB0611595D0

Abstract

A sterile wipe package comprising at least a first and a second compartment, wherein: the first compartment 7 contains a dry wipe impregnated with a biocide; the second compartment 6 contains a liquid for activating the biocide; the contents of the compartments are sterile; the compartments are separated by a barrier 5 to keep the contents of the compartments separate during storage; and the barrier can be opened to allow impregnation of the dry wipe in the first compartment with the liquid from the second compartment prior to opening of the package. Also provided are methods for making sterile wipes from such packages. A label 12 may include a roundel 13 that changes colour upon exposure to gamma-radiation at a level sufficient to achieve sterility. The biocide may comprise a chlorine release agent such as a dichloroisocyanurate, and may be sporicidal after activation. The wipe may comprise non-woven textile.

Description

1 2439059

STERILE WIPE PACKAGE

The present invention relates to a sterile wipe package, and to the supply of sterile disinfectant wet-wipes from such a package.

Disinfectant solutions and ready-impregnated disinfectant wet wipes are widely used within validated clean rooms and sterile work areas in biological, biochemical, pharmaceutical and medical facilities.

Such disinfectants and pre-impregnated wet wipes must be intrinsically sterile along with their packaging and delivery systems when brought into service, so as not to compromise the validation of the facility in which they are to be deployed.

Gamma (-y) irradiation at appropriate flux (25-40 kGy) is commonly employed in order to sterilise these items contained within multiple layers of packaging. Successive layers of over-wrap are discarded progressively as the items proceed from general storage into the closed sterile environment.

Existing disinfectant wet wipes which are effective against certain spore-forming micro-organisms rely for their effectiveness upon their ability to make available oxidative free radicals comprised of labile oxygen and/or halide or oxyhalide (hypohalite) ions which rapidly disable life processes that are otherwise protected within the spore.

By their very nature such radicals are unstable in storage and difficult to deliver quantitatively in reliably validated form. Gamma irradiation promotes premature decomposition and loss of useful free radicals in an unpredictable way. Such radicals and solutions are therefore traditionally prepared freshly for immediate use within the sterile facility. This is wasteful, time-consuming and requires to be validated on a batch by batch basis at point of use by skilled staff.

W093/100l9 describes a package for storing disinfectant wipes. The package has a first compartment containing a liquid component, a second compartment containing a powder disinfectant component and means actuatable to permit the two compartments to communicate to allow mixing of the powder component with the liquid component, wherein one of the compartments also contains a textile component which is impregnated with the liquid mixture before the package is opened. The disinfectant composition is preferably based on a mixture of a water-soluble inorganic halide and a strong oxidising agent such as a persuiphate that reacts with the halide in the presence of water to release hypohalite ions. The packages are not sterilized, and could not be sterilized without substantial decomposition of the biocide.

In a first aspect, the present invention provides a sterile wipe package comprising at least a first and a second compartment, wherein: the first compartment contains a dry wipe impregnated with a biocide; the second compartment contains a liquid for activating the biocide; the contents of the compartments are sterile; the compartments are separated by a barrier to keep the contents of the compartments separate during storage; and the barrier can be opened to allow impregnation of the dry wipe in the first compartment with the liquid from the second compartment prior to opening of the package.

Generally, the package and contents are stable to y-irradiation before the barrier is opened. For example, the package and contents are stable to a typical sterilizing gamma flux of 25-40 kGy. The term "stable" signifies that less than about 10%, preferably less than about 2%, and most preferably less than about 1% of the wipe, the liquid or the biocide is chemically changed by the irradiation.

The package may be any suitable closed container such as a covered tray or a pouch.

Generally it is formed from sheet material. The sheet material is sufficiently durable to maintain sterility of the package contents during normal handling and storage, and in some embodiments to permit the application of pressure to one compartment to break the sealing barrier between the compartments. The sheet material normally comprises at least one continuous layer of thermoplastic film. Suitably, the sheet material may be a laminated sheet made up of more than one thermoplastic film layer. At least a portion of the sheet material may be transparent to allow inspection of the package contents. The package is completely impermeable to microorganisms (including spores and viruses) before opening. The sheet material making up the package may further comprise a metal layer, such as an aluminium layer, to render the material air-and light-impermeable.

Suitably, the package is a pouch, that is to say it comprises a body consisting essentially of the flexible sheet material. The pouch may, for example, be a so-called pillow pouch, typically formed by continuous form-fill-seal equipment, or it may be formed by bonding together front and back faces of flexible sheet materials around their marginal edges. The total thickness of each flexible wall of the pouch is suitably in the range of from 50 micrometers to 1000 micrometers, for example 100 micrometers to 500 micrometers.

The package may be provided with a nip and/or a line of weakness and/or a tear strip to allow it to be opened after impregnation of the wipes inside the package.

Suitably, the barrier can be opened by applying pressure to the second compartment.

This can be done, for example, by applying pressure to the second compartment manually, or by manipulating the second compartment. For example, a minimum gauge pressure in the second compartment of from 0.1 bar to I bar may be sufficient to open the barrier.

In certain embodiments, the barrier may comprise a rupturable partition. For example, the partition may be a sheet having a line or region of weakness, for example a score line, that ruptures when pressure is applied across the sheet.

In preferred embodiments, the package comprises front and back faces of sheet material that are sealed together in a sealing region to form the barrier, and application of pressure to the second compartment causes the front and back faces of sheet material to peel apart along in the sealing region to open said barrier. The sealing strength between the front and back sheets in the sealing region is selected so that the sheets peel apart when a predetermined minimum pressure is applied to either compartment. The seal in the sealing region may for example be a thermal seal, an ultrasonic seal, a cold seal, or a seal formed by a layer of pressure-sensitive adhesive. In any case, the seal prevents flow of liquid from the second compartment to the first compartment prior to application of pressure as hereinbefore described. Details of thermoplastic films suitable for forming multi-compartment packages wherein a relatively weak thennal seal separates two compartments of the package are given for example in W02004/058594.

Suitably, the wipe or wipes in the first compartment comprise any disposable absorbent sheet material, including sponge sheets, woven or knitted textile sheets, non-woven textile sheets such as carded webs, spunbonded webs, melt-blown webs and air-laid webs, and/or wet-laid sheet materials such as absorbent papers or hydraulically entangled webs. Suitably the wipes consist essentially of the biocide and the absorbent sheet material. Suitably, the absorbent sheet material consists essentially of fibres that are substantially stable to gamma-irradiation, such a cellulose or cellulose derivatives such as viscose.

Preferably, the biocide after activation with the liquid is sporicidal. Suitable dry biocides that are stable to gamma irradiation include chlorine release agents, i.e. compounds that release chlorine in the presence of water.

The chlorine release agent may for example be selected from the group consisting of N,N-dichiorazodicarbonamidine; sodium p-toluene sulphonchloramide; p-toluene sulphon-dichioramide; sodium benzene sulphonchloramide; succinchloride; p-sulphon-dichloramidobenzoic acid; 1, 3 -dichloroo-5 -5-diethyl hydantoin; trichioroisocyanuric acid; sodium dichioroisocyanurate; sodium dichloroisocyanurate dihydrate; potassium dichloroisocyanurate; trichloromelamine, and mixtures thereof. The preferred biocides are dichloroisocyanurates, in particular sodium dichioroisocyanurate dihydrate (NaDCCN). Dry biocide-containing wipes impregnated with chlorine release agents are described in W090/02 166.

The wipes may further comprise other compounds such as a detergent, for example sodium alklybenzene suiphonate, or sodium lauryl sulphate, or a detergent builder, for example sodium carbonate, sodium metasilicate, or sodium sulphate.

A dye that it is bleached by chlorine may be incorporated into the wipes to provide a visual indication of the status of the tissue with regard to the exhaustion of its disinfecting properties.

The biocide and other optional ingredients may be incorporated into the wipes in any suitable fashion. For example, they may be impregnated into the wipes in a suitable inert solvent, followed by removal of the solvent. Particles of the biocide and optional other ingredients may be incorporated during the fabrication of the wipes, for example during carding or air-laying. In alternative embodiments, one or more layers of the biocide and optional other ingredients may be incorporated in a multilayer wipe. In certain embodiments, the biocide and optional other ingredients may be combined with a thermoplastic or adhesive composition and bonded thereby to the wipes. Suitably, the biocide is incorporated in the wipes at a basis weight of from ito 100 gsm (grams per square meter), for example from 2 to 50 gsm. However, these ranges are indicative only, since the basis weight of the wipes can vary widely, and the amount of biocide is varied correspondingly in order to achieve the desired final concentration of chlorine in the liquid.

Suitably, the first compartment contains from 1 to 250 wipes, for example from 5 to 100 wipes.

Suitably, the liquid inside the second compartment comprises water, and preferably it consists essentially of water. Suitably, the amount of liquid inside the second compartment is sufficient to impregnate all of the wipes in the first compartment, whilst being completely absorbed by the wipes so that there is no liquid in the pouch after impregnation.

Suitably, the biocide is present in the first compartment in an amount relative to the liquid in the second compartment sufficient to provide a final solution after impregnation having the desired biocidal properties. Suitably, the biocide such as a chlorine release agent is present in the first compartment in an amount relative to the liquid in the second compartment sufficient to provide a solution that gives a log reduction in spore count of at least about 3.0 according to the EN137004 protocol.

It has been found that, for the chlorine release agents, a concentration of from about 0.1% to about 1% w/w, preferably from about 0.15% to about 0.5%w/w in water provides the desired solutions.

Preferably, the chlorine release agent is present in the first compartment in an amount relative to the liquid in the second compartment sufficient to provide a total chlorine concentration in the liquid of from about l000ppm to about 3000ppm by weight. That is to say, the amount of chlorine release agent in the first compartment and the amount of liquid in the second compartment are selected such that the total chlorine in all chemical forms in the solution after impregnation is in this range. Of course, not all of the chlorine in the solution is available to act as a biocide. Some may still be in chemical forms that are relatively inactive. However, preferably, the chlorine release agent is present in the first compartment in an amount relative to the liquid in the second compartment sufficient to provide a free chlorine concentration in the liquid of at least about l000ppm, for example from about l000ppm to about 3000ppm by weight. The "free" chlorine concentration is measured using colour-change test strips available from numerous suppliers under the Registered Trade Mark SENSAFE and described in US patent 5,491,094.

It has been found that the free chlorine content and the sporicidal activity of the chlorine release agents are substantially enhanced if the liquid in the second compartment is acidified. For example, it may be an aqueous acid, preferably having pH in the range of from about 1 to about 4, preferably about 2 to about 3. The water may be buffered to acid pH with suitable buffer systems. Suitable acids and buffers include those based on organic carboxylic acids such as citric acid. The most preferred acidulant/buffer system is acetic acid/acetate.

Accordingly, the currently most favoured system is based on a chlorine release agent, preferably a dichloroisocyanurate, as the biocide, and acidified water (pH 2-4) as the liquid in the second compartment, the relative amounts being adjusted to about 0.iwt.%- 0.2wt.% biocide based on the weight of the water.

Suitably, the package according to the present invention is sterile both inside and out, and is contained within one, two or more successive layers of microorganism-impermeable outer packaging to maintain sterility. The multiple layers of packaging are discarded progressively as the products proceed from general storage into the closed sterile environment.

Suitably, the package according to the present invention further comprises a sterility indicator that gives a detectable, e.g. visual indication when the package has been exposed to a sterilising dose of gamma irradiation.

In a second aspect, the present invention provides a method of providing a sterile, biocidal wet-wipe, said method comprising the steps of: providing a multi-compartment package according to the first aspect of the invention; and opening the barrier to impregnate the wipes with the liquid inside the package. The package remains sealed from the environment during the impregnation step.

It will be appreciated that any feature or embodiment that has been described in relation to the first aspect of the invention is applicable also to the second aspect of the invention.

Since the contents of each pouch are reliably predetermined and hermetically contained prior to deployment, individual validation at point of use is obviated. By this invention we achieve significant operational and economic advantage within sterile facilities.

An embodiment of the present invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows a plan view of a package according to the present invention; and Fig. 2 shows a cross-sectional view along TI-Il of the package shown in Fig. 1.

Referring to the drawings, the package 1 is a flexible pouch formed by sealing together front and back faces 2,3 of flexible sheet material around margin 4. The flexible sheet material is a laminate comprising a barrier layer of aluminium metal foil, an outer plastics layer (which may comprise one or more sub-layers to provide adhesion, barrier properties or printability in known fashion), and one or more inner thermoplastic sealing layers. The front and back faces 2,3 are bonded together around margin 4 by the application of heat and pressure, i.e. by conventional thermic sealing.

A further continuous, liquid-tight barrier seal 5 is provided across the package to divide the package into an upper compartment 6 and a lower compartment 7. The barrier seal 5 is formed in the same way as the marginal seals, but the barrier seal 5 is designed to peel apart more readily than the marginal seals 4. For example, the barrier seal 5 may be narrower than the marginal seals 4. Alternatively or additionally, the barrier seal 5 may be formed using a lower sealing pressure and/or temperature and/or sealing time than the marginal seals 4. The flexible sheet material may be specially adapted for the formation of peelable barrier seal 5, for example the thermoplastic sealing layer may comprise more than one thermoplastic having different characteristics for providing two distinct sealing strengths under different sealing conditions. Suitable thermoplastic laminates and methods for forming compartmented pouches for separate storage of components to be mixed in the pouch immediately before use are described, for example, in EP-A- 1562 and WO-A-2004058594.

The upper compartment 6 of the pouch contains water 8 acidified with about 1 000ppm by weight of acetic acid (pH about 3). The lower compartment 7 of the pouch contains a stack of absorbent wipes 9 impregnated with sodium dichloroisocyanurate in a total amount of about 0.lSwt.% based on the weight of the water in the second compartment.

The relative amounts of NaDCCN and water are selected to give a final concentration of chlorine in water after mixing of about I 000ppm. The total amount of water is selected to provide both complete impregnation of the wipes 9 and complete absorption of the water 8 by the wipes.

Nips 10 in the margin 4, and a line of weakness 11 across the lower compartment, are provided to assist opening of the lower compartment 7 after impregnation of the wipes inside the package.

A label 12 is provided on the package 1. The label 12 includes an indicator roundel 13 that changes colour upon exposure to gamma-irradiation at a level sufficient to achieve sterility, thereby providing a positive indication that the package has been sterilized.

The package of Fig. 1 is manufactured as follows. First, the front and back faces 2,3 are bonded together along margins 4 and barrier seal 5, but leaving ends 14 and 15 open.

The compartments 6 and 7 are then filled with water 8 and wipes 9, respectively, and the ends 14 and 15 are then sealed. The filling and sealing of compartments 6 and 7 may be carried out in any order. The label 12 may be attached at any stage of the process.

In use, the package of Fig. 1 is sealed inside one or more microorganism-impermeable outer packages, and is then sterilized by exposure to 25-4OkGy of gamma irradiation.

The package is stable to irradiation and has extended storage time in the sterile state.

The outer layers of packaging are discarded progressively as the products proceed from general storage into the closed sterile environment where the wipes are needed. Finally, the package is activated by squeezing the upper compartment 6 to rupture the barrier seal and release the water 8 into the wipes 9. Once absorption of the water into the wipes is complete, the lower compartment 7 is opened by tearing along line of weakness 11 and the activated wipes are removed for use.

It has been found that solutions containing 0.lSwt% of NaDCCN and l000ppm of acetic acid in water give a log spore reduction determined according to EN137004 of about 4.5, which is well within the desired range for use in clean room environments.

The above embodiment has been described by way of example only. Many other embodiments falling within the scope of the accompanying claims will be apparent to the skilled reader.

Claims

CLAIMS

I. A sterile wipe package comprising at least a first and a second compartment, wherein: the first compartment contains a dry wipe impregnated with a biocide; the second compartment contains a liquid for activating the biocide; the contents of the compartments are sterile; the compartments are separated by a barrier to keep the contents of the compartments separate during storage; and the barrier can be opened to allow impregnation of the dry wipe in the first compartment with the liquid from the second compartment prior to opening of the package.

2. A sterile wipe package according to claim 1, wherein the package and contents are stable to y-irradiation before the barrier is opened.

3. A sterile wipe package according to any preceding claim, wherein the barrier can be opened by applying pressure to the second compartment.

4. A sterile wipe package according to any preceding claim, wherein the barrier is a rupturable partition.

5. A sterile wipe package according to claim 3, wherein the package comprises front and back faces of sheet material that are sealed together in a sealing region to form said barrier, whereby application of pressure to the second compartment causes the front and back faces of sheet material to peel apart along in said sealing region to open said barrier.

6. A sterile wipe package according to any preceding claim, wherein the biocide after activation with the liquid is sporicidal.

7. A sterile wipe package according to any preceding claim, wherein biocide comprises a chlorine release agent, preferably a dichloroisocyanurate.

8. A sterile wipe package according to claim 7, wherein the chlorine release agent is present in the first compartment in an amount relative to the liquid in the second compartment of from about 0.1% to about 1% w/w, preferably from about 0.15% to about 0.5%w/w.

9. A sterile wipe package according to claim 7 or 8, wherein the chlorine release agent is present in the first compartment in an amount relative to the liquid in the second compartment sufficient to provide a total chlorine concentration in said liquid of from about l000ppm to about 3000ppm by weight.

10. A sterile wipe package according to claim 7, 8 or 9, wherein the chlorine release agent is present in the first compartment in an amount relative to the liquid in the second compartment sufficient to provide a free chlorine concentration in said liquid of from about l000ppm to about 3000ppm by weight.

11. A sterile wipe package according to any of claims 7 to 10, wherein the chlorine release agent is present in the first compartment in an amount relative to the liquid in the second compartment sufficient to provide a solution that gives a log reduction in spore count of at least about 3.0 according to the EN137004 protocol.

12. A sterile wipe package according to any of claims 7 to 11, wherein the liquid in the second compartment is an aqueous acid, preferably having pH in the range of from about 1 to about 4.

13. A sterile wipe package according to any preceding claim, wherein the wipe comprises a non-woven textile material.

14. A sterile wipe package according to any preceding claim, wherein the first compartment contains from 1 to 250 wipes.

15. A sterile wipe package according to any preceding claim, wherein the package is sterile both inside and out, and is contained within one or more further layers of microorganism-impermeable packaging to maintain sterility of the package before use.

16. A method of providing a sterile, biocidal wet-wipe, said method comprising the steps of: providing a multi-compartment package according to any of claims 1 to 15; and opening the barrier to impregnate the wipes with the liquid inside the package.