US3618283A - Method for sterile packaging of articles - Google Patents

Abstract

A QUANTITY OF SOLUTION HAVING A KNOWN CONCENTRATION OF ONE OF A GROUP OF ANTISEPTIC AGENTS IS SEALED TOGETHER WITH THE ARTICLE TO BE STERILIZED IN A FLEXIBLE, AIR-TIGHT CONTAINER, AND THEN THE ARTICLE AND CONTAINER ARE WORKED SO THAT THE ANTISEPTIC SOLUTION SATURATES THE EXPOSED SURFACES OF THE ARTICLE AND CONTACTS THE ENTIRE INTERIOR SURFACE OF THE CONTAINER. THE ENTIRE PACKAGE IS THEN HEATED

TO A TEMPERATURE IN THE RANGE 120*F. TO 212*F. FOR A PERIOD OF THREE TO TWENTY-FOUR HOURS, DEPENDING ON THE AGENT USE, AND SUFFICIENT TO KILL ALL BACTERIA, FUNGI, AND SPORES IN THE PACKAGE.

Description

Nov. 9., 1971 F. c. MOORE ETAL METHOD FOR STERILE PACKAGING OF ARTICLES` 2 Sheets-Sheet 1 Filed NOV. v4, 1969 Nov. 9, 1971 F, C, MQORE ETAL 3,618,283

METHOD FOR STERILE PACKAGING OF ARTICLES Filed Nov.` 4, 1969 2 sheets-sheet 2 l 5 32 y O g l?, 116 @5913' 1i l l //C/w/ cal/@If 38 u" m 110 S 3o 9mm-.s @me United States Pate-'nt ce Patented Nov. 9, 1971 U.S. Cl. 53-21 FC 26 Claims ABSTRACT OF THE DISCLOSURE A quantity of solution having a known concentration of one of a group of antiseptic agents is sealed together with the article to be sterilized in a flexible, air-tight container; and then the article and container are worked so that the antiseptic solution saturates the exposed surfaces of the article and contacts the entire interior surface of the container. The entire package is then heated to a temperature in the range 120 F. to 212 F. for a period of three to twenty-four hours, depending on the agent used, and suicient to kill all bacteria, fungi, and spores in the package.

RELATED APPLICATIONS This application is a continuation-in-part of an earlier application of Francis C. Moore and Leon R. Perkinson for Method for Sterile Packaging of Resilient, Absorbent Pads, S.N. 788,480, tiled Jan. 2, 1969 (now abandoned) which is a continuation-in-part of an application of the same inventors for Method for Sterile Packaging of Resilient, Absorbent Pads, S.N. 725,826, led May 1, 1968 (now abandoned).

BACKGROUND AND SUMMARY The present invention relates to a method of packaging articles such as resilient, absorbent pads or Sponges of the type which might be used by a surgeon for scrubbing his hands in preoperative procedure wherein the entire interior of the container and its contents are sterilized after it is sealed and remain sterile until opened for use.

As is commonly known, the growing vegetative cells of most bacteria are killed much more easily than are the spores of the same bacteria. In the past, confusion has arisen by the use of the term sterilization or bactericidal to cover the situation wherein the vegetative cells alone are killed. In the present application, the word sterilization is used in its strict sense to mean a pro cedure that guarantees the destruction of all forms of microbial life so that the spores cannot be rejuvenated by any known technique.

In publication No. 437 of the U.S. Public Health Service, part 73, 73.37(e), sterilization is dened as the complete destruction of contaminating, living organisms, including living spores.

Another area requiring attention is the type of test used to determine whether or not a thing is sterile. The sporicidal test recommended by The Association of Oliicial Analytical Chemists suggest that for test organisms, one species of a Clostridia or Baclli strains of Bacillus substilis and Clostridium sporogenes should be employed. The tests carried out in determining the results of the present invention are in accordance with the specification of the A.O.A.C. Procedure.

Although persons skilled in the art will readily appreciate that the present invention is not limited to the packaging of any particular type of article but rather pertains to broad classes of articles such as catheters, hypodermic needles, sutures, etc., nevertheless, the invention will be described in detail in connection with the sterile packaging of a surgeons scrub sponge wherein it is desired to include a sufficient supply of soap in the package to permit a surgeon to conduct a pre-operative scrub without adding water to the contents of the package after opening.

Heretofore, the principal methods for sterilizing solid articles prior to packaging include steam sterilization, dry-heat sterilization, gas sterilization, sterilizing by irradiation, and fractional sterilization. Steam sterilization is carried out in an autoclave and employs saturated steam under pressure. There are many products which, of course, are incapable of withstanding such treatment. The temperature at which autoclaves operate is usually 121 C. as measured by a thermometer located in the steam discharge line of the autoclave. Further, to subject a sealed container to this temperature, a pressurized atmosphere would be required, so usually the articles are sterilized and then packaged aseptically.

Dry-heat sterilization is normally carried out in an oven specifically designed for the purpose. The oven may be heated by gas or electricity; but since dry heat is less eicient in sterilizing than moist heat, higher temperatures and longer periods of exposure are required than with autoclaving. Dry-heat sterilization is carried out frequently at l60-170 C. for a period of two to four hours. Again, it is assumed that the articles being sterilized are capable of withstanding such temperatures.

Gas sterilization requires specialized equipment designed for the particular purpose; and if carried out prior to packaging, then the packaging must be effected aseptically. Further, some procedures for gas sterilization are not as eiective as others.

For example, although ethylene oxide has been widely accepted and has received official recognition as a sterilizing agent, in reality its sterilizing capability varies widely with the procedure used. A commercial process employing pre-humidiiication, heating and evacuation of the chamber, high concentrations of the gas and operating cycle as long as twenty hours will result in sterilization. However, the ethylene oxide sterilization methods being carried out in some hospitals and medical offices are not nearly as reliable or eiective. See, for example Disinfection, Sterilization, and Preservation, Lawrence and Block (Lea and Febriger 1968), chapter 32. Further, gas sterilization is undesirable because of the formation of residuals as glycol in the presence of water.

Techniques are available for the sterilization of some types of pharmaceutical products by gamma rays and by cathode rays, but the application of such techniques is limited because the highly specialized equipment required and the harmfful eiects of irradiation on products and their containers.

Fractional sterilization (or Tyndallization) requires the heating of the article on each of three or more successive days to a temperature high enough t0 kill vegetative cells, but insufficient to kill spores. Spores that germinate in the period between successive applications of heat are killed, but the process is primarily suited to sterilization of liquids, and is not satisfactory for solutions containing non-n-utritive material because bacterial spores may fail to germinate in these materials during the periods between heat treatments.

Wit-h regard to specific articles, surgeons scrub sponges containing a dried soap to be used in cleansing the surgeons hands are known. After these Sponges are impregnated with a soap solution, they are dried, and then gas-sterilized (using ethylene oxide or propylene oxide) or sterilized by irradiation. When is is desired to use the sponge, water must be added t put the soap into solution. However, it has been found that this method of sterilizing is not satisfactory in that it is difficult to completely and reliably effect a bactericidal condition in the packages of sponges using this method.

Although methods of sterilization other than gas sterilization are desired for this purpose they have not proved successful. For example, it has been found that the steam sterilization of sealed packages of articles enclosed in conventional plastic containers will cause the containers to rupture at the temperatures induced. The heat causes expansion of air trapped in the package, and the temperatures required in autoclaving increase the vapor pressure of liquids in the package enough to cause it to rupture. The problem 0f trapped air becomes even more accentuated when the article desired to be packaged is a sponge, as with the present invention. Those packages which are intended to be sterilized by steam or heat usually have air-permeable containers so that they must be sterilized just prior to use, or they are rst sterilized and then packaged aseptically. The present invention, on the other hand, contemplates sterilization of the entire contents of the package after it has been sealed, and establishment of a bactericidal condition that pervails until the package is opened for use.

In its broadest aspects, the present invention contemplates sealing an article in a flexible container with a predetermined amount of a sterilizing agent in liquid form. Effective germicidal agents include a soap solution with 1 to 2% hexachlorophene, a solution of an iodophor, a 3% solution of parachlorometahexanol, a 1 to 5% solution of Merthiolate, and an aqueous 3% solution of Zephiran. After sealing, the package is kneaded, rolled or otherwise worked in order to completely contact all interior surfaces of the container and all exposed surfaces of the articles with the germicidal solution. The package is then heated and held within a temperature range below the boiling point of the liquid for a predetermined time sufficient to destroy all bacteria, fungi, and spores. The time and temperature values depend to some extent on the concentrations and agents used, but in any event rupture of the package is prevented and a complete sterilization of the articles is effected.

In one embodiment, a predetermined amount of a liquid sterilizing or antiseptic agent is introduced into an envelope or at type of container. The pad or sponge which is to be packaged is also placed in the container; and the container sides are then forced together so that it assumes a reduced volume. Thus, the antiseptic or germicidal agent contacts the sponge, is absorbed by it, and most of the air is expelled from the container. Then the package is sealed, and further squeezed so that the sponge assumes an even reduced volume and the antiseptic agent completely wets the interior of the sealed package.

When the sponge is then released, it will expand slightly thereby absorbing substantially all of the antiseptic agent for subsequent use, yet leaving the entire package and its contents wet. The package is then heated to destroy all bacteria, fungi and spores in it; and the package remains sterilized until used.

In an alternative embodiment, a soap or detergent solution containing a liquid germicidal agent is deposited into the pad as it is conveyed down a line. Next, the pad is packaged in laminated flexible sheet material having an interior coating of rubber-modified linear polyethylene. Then the package is squeezed so that the solution forms suds to contact the entire contents and interior walls of the package. Next, the package is heated at suflicient temperature and time to destroy all bacteria, fungi and spores in it; and enough liquid is retained by the pad for a surgical scrub when the package is opened for use.

In both 0f the above-described embodiments, the com- 4 bination of germicidal agent, container material and sterilization parameters permit the establishment of a bactericidal condition in a sealed, air-tight package of a surgeons scrub sponge at sufficiently low temperature to avoid rupture of the container.

Thus, the inventive method provides a convenient, inexpensive, and reliable process for sterilizing articles and the inner surfaces of a sealed, flexible container for the articles and for packaging the article with the assurance that the package and its contents will remain sterile during storage and shipment, and thereby be ready for use as soon as it is opened without additional sterilizing. At the same time, the package, in the case of the sponge, contains a sterilized soap solution which may be used in cleaning and scrubbing a surgeons hands.

Other features and advantages of the present invention will be obvious to persons skilled in the art from the following detailed description of a preferred embodiment accompanied by the attached drawing.

THE DRAWING FIGS. l-6 illustrate the various steps of one embodiment for packaging a sponge according to the present invention; and

FIGS. 7-13 illustrate an alternative method of packaging according to the present invention.

DETAILED DESCRIPTION Turning first to FIG. 1, there is seen a container or bag generally designated 10 which preferably is made of two at sheets sealed together on three sides including a bottom 10a and two sides, thereby leaving an aperture at the top which is designated in the drawing by reference numeral 11. The container is held in an upright position as shown `by apparatus which is not illustrated since it forms no part of the invention. The sheets are formed from any suitable material which has the properties of flexibility and liquid and gas impermeability. The preferred sheet material (described in greater detail within) is a laminate with a rubber-modified linear polyethylene interior 12 with a Mylar backing 13. Polyethylene, or other heat scalable plastic material 14, may be applied about the inner portion dening the aperture 11.

A predetermined amount of liquid antiseptic agent 15 containing a germicide and a quantity of liquid soap or detergent is placed in the pouch-shaped container 10. While any suitable liquid germicide may be used, effective results have been obtained with hexachlorophene, having a concentration in the range of between 0.2% to 10% by total liquid weight in a conventional liquid soap solution. For the packaging of a surgical scrub sponge, the soap solution may have a volume of between 1.0 and 40 cc., a preferred formulation being about 4 cc. of liquid soap and 20 cc. of water. Other sterilizing or antiseptic agents may be used; but it is desired that the antiseptic agent not only be capable of sterilizing the sponge and the inner surface of the bag after the package is sealed, but also of being used as thc cleansing solution with which a surgeon scrubs his hands.

A sponge generally designated 16 in FIG. 2 is also inserted into the container 10 through the open end `11, and this may, of course, be done before or after the antiseptic agent is introduced.

The sponge 16 may be any resilient, absorbent scrub pad such as the one disclosed in our co-pending application for Scrub Pad and Method of Making, filed May 1, 1968 Ser. No. 725,823 (now abandoned). It will be obvious, however, that the present invention is not so limited-it is a more general method for sterilized packaging of solid articles. Since the method results in the sterilization of the bags inner surface and of the bags contents, it is apparent that the pad, at the time of insertion into the bag, may be in a non-sterile state.

Next, as seen in FIG. 3, first and second side pressure plates 17 and 18 are forced together to reduce the volume of the package thereby forcing air from the interior of the container and causing the solution 15 to penetrate the sponge V16 and contact a substantial portion of the interior surfaces of the container 10.

While the lvolume of the combination thus rendered as shown in FIG. 3, heated platens 19 and 20' (see FIG. 4) seal the polyethylene-coated interior sides of the foil 12 of the container. In the illustration given, the level of the liquid antiseptic is below the top of the fliexible bag; however, it is to be understood that effective heat sealing may be accomplished even though the volume of the package is reduced to a point Where the antiseptic solution spills over the top.

The function of the next step is to insure that the antiseptic solution has contacted the entire interior of the sealed package and all exposed surfaces of the article; and to accomplish this, the side pressure plates y1.7 and 18 further reduce the volume of the package and at least partially compress the sponge, thereby displacing some of the liquid antiseptic and causing the entire inner surface of the bag to be flushed with the germidical solution (FIG. Y

.Even though the sealing step may trap a pocket of air within the container (as at 21 in FIG. 4), or air may have been trapped in the sponge itself, the subsequent squeezing of the pad will cause the air and soap solution in the pad to form suds which will fill the upper pocket and contact the entire interior surface of the container surrounding this pocket.

An alternative method for insuring that the antiseptic solution 15 completely contacts or flushes the interior surface of the container and the entire surface of the article is to force the package between two rotatable rollers, as in FIG. 5A wherein the rollers are designated 22 and 23 and arranged to rotate about axes perpendicular to the plane of the drawing. Thus, the solution 15 will be partly forced from the sponge 16 adjacent the surface being compressed; and it will form suds to contact the entire interior surface of the container. Equivalnet techniques for working or kneading the sealed, flexible package will be apparent to persons skilled in the art.

Next, the plates 17 and 18 are released; and the resiliency of the sponge 116 causes it to assume a slightly expanded width, as illustrated in FIG. 6, and to re-absorb the excess antiseptic agent from the sides of the package. This collapses the sidewalls of the container 10` about the periphery of the sponge; and the antiseptic agent saturates the sponge and is thus stored in the sponge for subsequent use as a hand cleansing agent. When the container 10` is torn open as it is desired to use the sponge 16, there is no excess spillage of the antiseptic agent since it has impregnated the sponge 16; and further, substantially all of the antiseptic agent which had ordinarily been placed within the container is available for use.

Finally, the package is heated to a sucient temperature and for a suflicient time to destroy all bacteria, fungi and spores within the package. Although the heating step is preferably carried out by the application of hot air to the sealed package, as illustrated schematically in FIG. 13, it will be appreciated that alternative heating methods may be as equally effective. For example, radiant lamps and gas or electrically heated air may also be employed.

However, heating with hot air is preferred because it has been found that a completely bactericidal condition can be created within the package at unusually low temperatures with the antiseptic agents used herein-thus eliminating the treat of rupture while insuring a germfree sponge.

Because air will ordinarily be trapped in the package (either in the pad itself or in the peripheral interstices between the pad and the container), the package Will expand slightly as it is heated, according to the temperature to which it is heated.

Turning now to FIGS. 7-13, an alternative and preferredpmethod of sterile packaging the scrub pads will now be described in detail.

The sponge is generally designated by reference numeral 16, and individual Sponges are conveyed along a conveyor 25 in the longitudinal direction of the sponge 16. As the sponge 16 passes beneath an end portion of a conduit 26, which is connected to a source (not shown) of the antiseptic agent, the liquid antiseptic agent together with the soap or detergent solution, generally designated by reference numeral 27, is forced or squirted onto the top of the sponge. It has been found that embedding a number of needles directly into the sponge enables the introduction of larger quantities of the liquid in minimum time. Since in preferred quantities, the amount of the germicidal agent released per sponge is about 25-3'0 cc., and since the expanded dimensions of the sponge 16 may typically be 3'1/2 in. by 21/2 in. by 11/2 in., the entire volume of antiseptic agent is held by the sponge.

The sponge is then conveyed, as seen in FIG. 8, to an area where it is placed on a flat sheet of the container material generally designated 28. In this embodiment, the container material 28 is a laminate having an upper layer (which is to become the interior surface of the finished package) of a rubber-modified linear polyethylene extruded film such as the butadiene-modified linear polyethylene lm marketed under the trade name Visotherm and manufactured by the Visqueen Company of Terre Haute, Ind. This type of material has a very high melting point; and even though it is heated for an extended period, it will not crack easily, thereby retaining its liquid and gas impermeability for long periods of time. Further, it is heat scalable.

The polyethylene film 29 may be backed with any suitable non-porous and substantially non-stretchable yet flexible sheet material 30 such as Mylar, paper, cellophane, or metal foil (or combination paper and foil). The outer layer functions as a non-stretchable shell which is capable of withstanding the internal pressures developed during heat sterilization. The butadiene-modified linear polyethylene serves as a non-rupturing liner and appears to conform to the surface irregularities and wrinkles of the non-stretchable outer layer without giving way under the forces exerted at the temperatures of interest.

As seen from the side of FIG. 8', the sponge is conveyed longitudinally and the sides of the container material 30 are folded up and around the sponge 16 as seen in FIG. 9. Adjacent edges are then brought into contact with each other to form an overlapping area above the sponge -16 as at 32. The overlapping portions are then heat-sealed together by means of heated plates 33 and 34 exerting opposing force against the overlapping edges 32. Alternatively, conventional molecular Weight polyethylene may be used as an interior coating on the rubber-modified polyethylene to form the gas and liquid impermeable seal by heating.

After the seal is formed longitudinally of the container so that it appears to be a continuous tube, similar heat plates 36 and 37 (see FIG. l0) are lowered transverse of the tube to seal the package at both ends. Adjacent packages are then separated by cutting the tube transversely and mid-Way of the transverse heat-sealed region so as to form end seals for each of the two adjacent packages. Alternatively, the individual packages could be severed prior to the transverse heat sealing.

In the transverse heat sealing, the overlapping edges 32 of the container 30 are folded over to lie at against the exterior of the container. Turning now to FIG. l1, the transverse heat-sealed areas are designated 38 and 39; and as previously mentioned, the overlapping edges 32 which extend longitudinally of the tube are also heatsealed. Thus, FIG. l1 is a top view of the sponge containing the aniseptic or germicidal agent after it has been packaged in an impermeable container of exible sheet material.

Turning now to FIG. 12, a pressure plate 40 is then forced into contact with the sponge to flatten it by about one-half its original depth, and thereby extract the antiseptic scrub solution and trapped air from the sponge in the form of a frothy suds which fills the interstices 41 and 42 at either end of the sponge as well as the side interstices and contacts the entire interior of the package. The exact pressure applied in order to accomplish the desired result depends upon the size of the sponge and upon its composition. However, for -25 cc. of soap solution containing hexachlorophene as described below, and with a three-layered sponge as described in the aboveidentified, co-pending application having a central layer of a resilient plastic foam which has approximately 60 cells or pores per lineal inch, sufficient suds are generated to entirely fill the package by compressing the sponge to about one-half its original height. The higher pore density of the central layer causes better sudzing action.

When the pressure is released and plate 40 removed from contact with the package, the resiliency of the sponge will force it to its original shape, thereby partially collapsing the package and reducing the volume of the end interstices 41 and 42. The sponge re-absorbs the antiseptic agent and holds it for further use. However, enough of the antiseptic agent remains in contact with the interior of the container to effect a bactericidal condition within the package when it is heated. Referring now to FIG. 13, an oven cavity is denoted by reference numeral 34, and it is provided with electrical heating coils 46 for heating the air in the chamber 45. The time and temperature of the heating step will, of course, depend upon many variables; but the most significant factors are the type, quantity and concentration of the antiseptic or germicidal agent used. Thus, the time and temperature sufiicient to destroy all bacteria, fungi and spores are best determined empirically, allowing a sufficient margin for reliability.

Once the entire interior of the package has been wet or contacted by the antiseptic agent, the heating step should take place as soon as possible thereafter to insureI the heating of the container and its contents while they are wet with the antiseptic agent. This has been found to reduce the heating temperature because sterilization of dry surfaces by heat takes a much longer time.

As just mentioned, the temperature at which the package is heated and the time during which it is heated depend upon the type of antiseptic agent employed, but it has been found that in any case, the temperature should be within the range of 120 F. and 212 F.; and it should be at least about minutes in time. The following example will afford a greater appreciation of this step in the process.

EXAMPLE I Standard laboratory sterility tests (i.e. the aboveidentified sporicidal test of the A.O.A.C.) were performed on wet scrub pads sealed in plastic film containers and prepared according to the inventive method. The pads were the multiple-layer, pillow-shaped sponges described in the above-described, copending application. Each package contained approximately 22 cc. 3% Hexa-Germ, a chlorophene-base antiseptic soap solution marketed by Huntington Laboratories, Huntington, Ind. In a first set of three of these packages, strips of Bacillus subtilis (globigii) spores were placed in the packages, which were then sealed, agitated and heated to a temperature maintained between 164 F. and 174 F. for a period of 8 hours.

Laboratory findings indicated that bacterial growth in various dilutions of the specimens after an incubation period was negative; and no microbic colonies were visible for an observation period of seven days, at which time the test was discontinued.

A second set of five packages containing the same spores were placed in an oven for about 71/2 hours where- 8 in the oven temperature was maintained between 173 F. and 183 F. Again, the findings indicated that bacterial growth after an incubation period was negative; and no microbic colonies were visible during an observation period of seven days.

EXAMPLE II For packaging a surgical sponge of the type described, preferred hexachlorophene antiseptic solution includes 27 cc. of water and 8 cc. of hexachlorophene antiseptic soap solution marketed under the trademark Dermasurgical by S. M. Edison Chemical Company, Jersey City, NJ. which contains a buffering agent for bringing the pH level down to about 4.5. Using this germicidal agent, a preferred temperature range is 165 (plus or minus 5) for a period of eighteen hours. Sterility is also achieved with this antiseptic agent in a period of six hours if the temperature is raised to 180 F.

If the amount of hexachlorophene is doubled, satisfactory results have been obtained with temperatures as low as 130 F. and heating time of ten hours. Again, laboratory findings indicate that bacterial growth in various solutions of the specimens after an incubation period of 7 days was negative.

EXAMPLE III In another sampling, the Sponges were impregnated with about 25 cc. of an aqueous solution of iodine-base (iodophor) soap, marketed under the designation Surgidine 'by Carter-Wallace, Inc., Cranbury, New Jersey, when diluted as directed. Strips of Bacillus subtilis (globgii) spores were again placed in tive sample packages. These packages were heated to a temperature of 150 F. for two hours. The strips of Bacillus globigii spores were resubcultured immediately upon removal from the oven; and no growth was obtained in any of the tubes containing the strips.

Satisfactory results have been obtained with the iodophor germicide and temperature ranges of 13G-140 F. for a period of 6 hours.

EXAMPLE IV In still another sampling, the surgical Sponges were sealed in a flexible container with 30 cc. of a soap solution containing 3% of a germicide sold under the mark PCMX (pharachlorometahexanol manufactured by Ottawa `Chemical Company, Toledo, Ohio) at a temperature range of 13G-140 F. for a period of 10 hours.

It is felt that a concentration range of 1-6% would be effective to insure sterility with a temperature above about F. and heating periods in the range of 8 to 20 hours, depending on the concentration and temperature.

EXAMPLE V An aqueous solution with 1 to 5% sodium ethylmercurithiosoalicylate, marketed under the designation Merthiolate by Eli Lilly & Company, Indianapolis, Indiana, has been found to be effective to sterilize the interior of the package if heated to a temperature of 140 for a period of 6 hours. lf the heating period is extended to as long as 20 hours, the temperature could be reduced to F.

EXAMPLE VI In the sterile packaging of a pre-operative swab, an aqueous solution of Zephiran (a benzalkonium chloride solution manufactured by Winthrop Laboratories, Inc., New York, New York) is effective if heated to a temperature within the range of 16C-170 F. for a period of 18 hours.

The inventive procedure thus provides a convenient, economical and reliable method for sterile packaging of scrub Sponges. Having thus described in detail two alternative embodiments of the invention together with examples, it will be apparent to persons skilled in the art that certain of the steps described may be modified in sequence and that equivalents may be substituted for the processes and components described without departing from the principle of the invention. It is, therefore, intended that all such modifications and substitutions be covered as they embrace within the spirit Iand scope of the appended claims.

rWhat is claimed is:

1. A method of sterile packaging of an article comprising sealing said article in a flexible container with a predetermined amount of a liquid sterilizing agent selected from the group consisting of hexachlorophene, iodophor, parachlorometahexanol, sodium ethylmercurithiosalicylate and benzalkonium chloride; flexing the walls of the sealed package to contact the entire interior surface of said container and exposed surface of said article with said agent; and heating said package at a temperature in the range of l20212 F. and for a period of time in excess of 30 minutes to sterilize said article and the interior of said container.

2. The method of claim 1 wherein said agent comprises a soap solution of l-6% hexachlorophene and wherein said sealed package is heated to Ia temperature within the range of 140-170" F. for a time between 14 and 20 hours and sufficient to destroy all spores.

3. The method of claim 1 wherein said agent comprises an aqueous solution of iodophor, and wherein said package is heated to a temperature within the range of 130- 150 F. for a period of 4-15 hours and suiicient to destroy all spores.

4. The method of claim 1 wherein said agent includes about 3% parachlorometahexanol, and said package is heated to a temperature within the range of 13G-140 F. for a period of 10-15 hours and suflicient to destroy all spores.

5. The method of claim 1 wherein said germicidal agent comprises a solution of l-5% sodium ethylmercurithiosalicylate and wherein said package is heated to a temperature in the range of 14C-160 F. for a period of -20 hours and suicient to destroy all spores.

6. The method of claim 1 wherein said germicidal agent is a benzalkonium chloride solution of 1 3 concentration, and wherein said package is heated to a temperature in the range of 140-160 F. for a period of 14-20 hours and suliicient to destroy =all spores.

7. A method of sterile packaging of resilient, liquidabsorbent pads comprising: applying a predetermined amount of liquid antiseptic agent to said pad whereby said agent is absorbed by said pad; sealing said pad and said absorbed agent in a flexible, impermeable container; then extracting said liquid agent from said pad while in said container to cause said agent to thoroughly contact the interior surface of said container; and heating the sealed package to a temperature below the boiling point of said liquid while said agent is in contact with the interior surface of said container and for a sufficient time to destroy all bacteria, fungi and spores in said container.

8. The method of claim 7 wherein said first-named step comprises: placing a predetermined amount of said liquid antiseptic agent in a flexible container having a scalable opening; inserting said pad into said container; partially compressing said container to assume a reduced volume, thereby expelling air from said container through said opening and causing said antiseptic agent to contact said pad; said step of sealing comprising then sealing said opening while the container is thus reduced in volume.

9. The method of claim 7 wherein said step of extracting comprises then further compressing said container and said resilient pad to cause said antiseptic agent to be squeezed from said pad and thoroughly contact the inside of said container.

10. The method of claim 9 further comprising after said step of pressing, the step of relieving compressive forces from said container and said pad whereupon said pad eX- l0 pands and absorbs substantially all of the excess of said antiseptic agent in said container, leaving the interior surface thereof wet.

11. The method of claim 7 wherein said predetermined amount of antiseptic agent is between l0 cc. and 40 cc. of a surgical scrub solution.

12. The method of claim 11 wherein said scrub solution container is between 0.2 and l0 percent hexachlorophene.

13. The method of claim 11 wherein said scrub solution is a detergent and said antispectc agent is an odophor.

14. The method of claim 7 wherein said first-named step includes squirting a predetermined amount of said antiseptic agent on said pad.

15. The method of claim 14 wherein said step of sealing includes placing said pad containing said antiseptic agent on a resilient, flexible sheet having one surface of heat-sealable material, pressing overlapping edges of said material together with heated members to form a tube about said pad, and pressing facing surfaces of said tube together while heating in a direction transverse of said tube to form seals at the ends thereof.

16. The method of claim 15 wherein said step of extracting comprises squeezing said package to force air and said solution in said pad to form a frothy suds to ll all interstices in said package.

17. The method of claim 15 further comprising the step of cutting adjacent packages along said transverse heat seals to provide heat-sealed edges for both adjacent packages.

18. The method of claim 17 wherein said antiseptic agent is between l0 cc. and 40 cc. of a surgical scrub solution containing between 0.2 and 10 percent hexachlorophene.

19. The method of claim 18 wherein said step of heating comprises raising the temperature of said package to at least 150 F. for at least about eight hours and sufficient to destroy all spores.

20. The method of claim 15 wherein said antiseptic agent is between 1 cc. and 30 cc. of an iodophor base detergent.

21. The method of claim 20 wherein said step of heating comprises raising the temperature of said package to at least about F. for at least about two hours and sutiicient to destroy all spores.

22. In a method of forming a sterile package containing a resilient pad impregnated with a liquid surgical scrub solution, the steps of bringing into contact a substantially dry, resilient, and liquid-absorbable pad and a. -germicidal liquid scrub solution so that said pad absorbs a predetermined amount of said solution; then sealing said pad holding said scrub solution in a flexible container; then flushing the entire inner surfaces of said container with the germicidal scrub solution contained therein to contact the entire inner surface of said container and said pad with the germicidal'solution, and then heating the sealed package to a temperature less than the boiling point of said solution for a period suicient to kill all organisms in said sealed package. v

23. The method of claim 22 in which said flushmg step comprises working said pad and container to redistribute the germicidal scrub solution within the contalner and force the solution into contact with said inner surface of said container.

24. The method of claim 23 wherein said step of working said pad is characterized by the formation of suds by forcing air and soap solution from said paid thereby to fill any interstices with the frothy germicidal scrub solution.

25. The method of claim 24 wherein the step of heating said sealed package while the interior of said container is Wet with said germicidal scrub solution to destroy all bacteria, spore and fungi in said package.

26. A method of sterile packaging of an article comprising sealing said article in a llexible containervwith a References Cited predetermined amount of a liquid sterilizing agent therein; UNITED STATES PATENTS exing the walls of the sealed container to contact the entire interior surface of said container and the surfaces 3,348,905 10/1967 RPVBIY 53-21 X of said article with said liquid sterilizing agent; and heat- 5 313991955 9/1968 Zlmmerman 21-58 ing said container and its contents at a temperature below the boiling point of said liquid agent and in the range of TRAVIS s MCGEHEE Pnmary Examiner 1Z0-212 F. for a period in excess of 30 minutes to U S C1 X R sterilize the interior of said container and the containers contents. 10 21-58; 53-25

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