CA2028354A1

CA2028354A1 - Substantially anhydrous complexes of pvp and h o

Info

Publication number: CA2028354A1
Application number: CA002028354A
Authority: CA
Inventors: John J. Merianos; Herbert A. Lieberman; Robert B. Login; Paul Garelick
Original assignee: GAF Chemicals Corp
Current assignee: GAF Chemicals Corp
Priority date: 1989-11-08
Filing date: 1990-10-23
Publication date: 1991-05-09
Also published as: WO1991007184A1

Abstract

ABSTRACT

What is provided herein are substantially anhydrous complexes of PVP and H2O2 in molar ratios of between about 2:1 and 1:1, respectively, which corresponds to between about 13% and about 23% by weight H2O2. The complexes of the invention are substantially uniform, free-flowing, fine white powders.
The complexes herein are prepared by reacting PVP
and H2O2 in substantially the molar ratio predetermined for the complex.
In one suitable process for preparing such complexes the reaction is carried out between the reactants in an anhydrous organic solvent such as ethyl acetate.
A method is provided herein for reducing the microbial content of surfaces which comprises contacting said surface with a microbiocidal amount of said free-flowing, substantially anhydrous complex of PVP and H2O2.

Description

This invention relates to substantially anhydrous complexes of polyvinylpyrrolidone (PVP) and hydrogen peroxide (H202) which are, free-flowing, uniform, fine white powders containing a predetermined amount of H2O2 therein.
Stabilized H2O2 compositions have found wide utility in commercial and industrial applications, e.g. as disinfectants, sterilization agents, as bleaching materials, washing concentrates, etchants, in cosmetic preparations, as clarification agents for alcoholic and fermented beverages, and as a catalyst in polymerizations requiring a free radical source. In biological applieations which require a disinfectant or sterilization agent, such H202 eompositions require release of an effectivQ amount of oxygen at a controlled rate without ~toraqe decomposition caused by interaction with organie matter, light and/or heat.
Shiraeff, in U.S. Patents 3,376,110 and 3,480,557, di~elose~ a solid, stabilized hydrogen peroxide composition of hydrogen peroxide and a polymerie N-vinyl heterocyclic compound prepared in an aqueous solution of the componentq. These compositions generally were prepared by mixing various weights of PVP and aqueous H2O2, and evaporating the solution to dryness. The Shiraeff eomposition, which was believed to be a solid, dry complex, was described as not necessarily anhydrous due to the hydrophilie nature of the PVP and the water present in the reactlon solution. Shiraeff further stated that such amounts of water could be tolerated, however, if it did not affect the solid dry characteristics of the complexe~. The H2O2 content of the composition was given as being at least 2%, and preferably 4.5 to 70% by weight. Prolonged -, : ~

,, - ~ , . , - , ~ , 2 ~

drying to remove water from such compositions, however, resulted in loss of H202 forming a brittle, transparent, gummy, amorphous product. In U.S. 3,480,557, the aqueous PVP-H202 complexes, upon heating to dryness, produced hard, brittle chips which had a variable H202 content ranging from about 3.20 to 18.07% by weight, depending upon the dryinq times.
In accordance with the invention, substantially anhydrous PVP-H202 complexes are provided having a predetermined molar ratio of PVP to H202 ranging from between about 2:1 to about 1:1, corresponding to a H202 eontent of about 13% to about 23%. The substantially anhydrous PVP-H202 complexes are prepared by reaction o~ PVP and H202 in a substantially anhydrous organic solvent and are obtained by filtration o~ the suspension as a uniform, free-~lowing, fine white powder.
The PVP polymerie starting material used in the pre~ent invention is available commercially as a solid of varying molecular weight, water solubility and water content. A typical PVP polymer i9 water soluble PVP-K30 (GAF Corp.) which contains less than 5% water. Other PVP
polymer~ o~ dif~erent molecular weight, water solubility and water content also may be used, as for example, K-90 and X-120; Polyclar AT; Crospovidone; and the like. Both water soluble and water insoluble PVP polymers may be used.
In this process, the PVP powder is suspended in a suitable anhydrous organic solvent, such as a carboxylic acid ester, an alkyl ether, e.g. t-butyl methyl ether, or a hydrocarbon, e.g. cyclohexane. Preferably, however, an alkyl or cycloalkyl ester of a saturated aliphatic carboxylic acid is used, as for example, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate and ethyl propionate. The PVP suspension in ethyl acetate, for example, then is cooled, preferably to about 0C., at which temperature precipitation of the desired complex as a ~ine powder may suitably occur.

; .

.
An anhydrous H202 solution in an anhydrous organic solvent, preferably the same carboxylic acid ester used to form the PVP suspension, then is prepared according to the proces~ of u.S. 4,564,514. In this step, an aqueous H202 solution (e.g. a 50% solution) is treated with the e~ter and then subjected to azeotropic distillation at a predetermined low pressure, e.g. at 200 mm Hg and 55OC. _ m e resultant product is an anhydrous H202 solution in the ester having a H202 concentration in the range of about 20 to 50% H202.
Thereafter the thus-prepared anhydrous H202 golution i~ 810wly added to the cooled PVP suspension in an anhydrous solvent in an amount corresponding to the desired molar ratio o~ PVP and H202. Preferably, however, a small excess of the H202 solution over the desired stoichiometric ratio is used. For example, to prepare a m -H202 complex with a 1:1 molar ratio, about 111 g.
PVP and 100 g. ot a 42% H202 and 300 ml o~ anhydrous ~olv nt i~ used, providing a small excess, e.g. about 5%, ov r the r-guired stoichiometric amount o~ 34 g. H202.
Thl~ xces~ H202 i~ recoverable ~rom the mother liguor.
Upon mixing the PVP and H202, a ~ine white powder i~ obtained which i9 ~iltered and dried at about 40-50-C. in vacuo to remove residual solvent. The product i~ a ~table, anhydrous complex in the form o~ a uni~orm, ~re--~lowing, fine white powder having a H202 content b-tw en about 13% (2:1 molar ratio) and 23% H202 (1:1 molar ratio). The water content o~ the product generally i~ egual to or less than the amount present in the PVP
starting matorial, and usually is les~ than 1%f preferably about O.S%.
An alternative process ~or preparing the substantially anhydrous complexes o~ the invention uses a water-insoluble PVP polymeric starting material which is available commercially as a solid o~ varying molecular , , . , :.
.. . .
... .
-. - . :. , - . .. .

a ~ ~

weight and water content. A suitable water-insoluble PvP
polymer is Crospovidone, sold by GAF Chemicals Corp., which eontains about 4% water. These PvP powders preferably are dried at about 105C. in vacuo for about 2 hour~ to reduce the water eontent to less than about 1%.
The dried PVP powders then are suspended at about 5-10C. under aqitation in a substantial quantity of an anhydrous organie solvent, sueh as a earboxylie aeid ester, a dialkyl ether, e.g. t-butyl methyl ether, or a hydroearbon e.g. hexane or eyclohexane. Pre~erably an alkyl or eycloal~yl ester of a saturated aliphatie carboxyli¢ aeid is used, as for example, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate and ethyl propionate. Ethyl acetate is preferred.
A 70-85% agueous H202 solution then is added to the eooled PVP suspension under eontinued agitation during a period o~ about 30 minutes to about 1 hour. The amount~ o~ PVP starting material and H202 solution used eorre~pond to the desired molar ratio of PVP and H202 ln th- eomplex. Pre~erably, however, a small excess o~ the H202 ~olution over the desired stoichiometric ratio i9 u~ed. Thi~ exces~ H22 is recoverable from the mother llquor.
Upon mixing the PVP and H202, a uniform, ~ree-~lowing, fine, white powder precipitate i5 obtained whleh ls ~iltered and dried at about 40-50C. in vacuo to romove residual solvent and water. The product is a stable, anhydrous complex in the ~orm o~ a uni~orm, ~ree-~lowing, ~ine, white powder having a H202 content between about 18 and 22% H202. The water content o~
the product generally is about 2% or less, and usually can be dried to less than about 1%.
Continued drying under these low temperature and vacuum conditions reduces the final water content in the eomplex to a substantially anhydrous powder with no loss o~

...... . .
, .
- :
- .
. , ~
, " , . . - -~ ~ s~

Preparation of SubstantiallY Anhydrous 1:1 PVP-H202 ComPlex PVP K-30 (GAF Corp.) (4.5% water), 111 g., was suspended in 200 ml. of anhydrous ethyl acetate (0.01%
H20), and the suspen~ion was cooled to oC. An anhydrous hydroqen peroxide solution in ethyl acetate was prepared by treating 200 g. of 50% aqueous hydrogen peroxida with 6 1.
of ethyl acetate and azeotroping in a rotary evaporator to remove 100 g. o~ water. A 42.7% H202 solution in anhydrous ethyl acetate was obtained. Then 100 g. of this solution was added slowly over a period of about 1-1/2 hours to the PVP suspension. A fine white precipitate formed which was filtered and dried in vacuo.
The rQsultant water soluble complex contained 23.4% by weight H202 and 0.5% by weight water, upon drying at 50C. in vacuo for 2 hours.

PrePara-tion o~ Anhydrous 2:1 PVP-H202 ComPlex The process of Example 1 was followed using 50 qO
of the H202 solution in anhydrous ethyl acetate. The resultant complex contained 13.2% H202 and 0.5% water.

200 g. of PVP-CI (K-30) was suspended in 300 g. of anhydrous ethyl acetate. Then H202, 424 g., 19.6 H202 and 0.84% H20 was added slowly to the cooled (5C.) suspension of PVP/ethyl acetate. The addition required 45 minutes. The suspension then was stirred for 3 ~ ~

another 45 minutes, filtered, and washed with anhydrous ethyl acetate. The fine powder was dried at 40-50C. for 2 hours under vacuum to recover ethyl acetate. The yield was 258.8 g. of water soluble PVP-H202 containing 23.1%
H202 and 0.4% H20 as a free flowing white powder.
The mother liquor of ethyl acetate, 485 g. contained 4.51%

EXAMPLE_4 35 g. of crospovidone wa~ suspended in loO ml. of anhydrous ethyl acetate. Then H202, 27.5 g. a~ a 42.7%
H202 solution wa~ added with cooling at 5-10C. The mixture was stirred for 1 hour. The precipitated complex wa~ filtered to provide 46.1 g. of a water insoluble PVP-H202 complex containing 24.9% H202, after drying at 40-50C. for 2 hours.

COMPARATIVE EXAMPLE

PreParation o~ Aaueous PVP-H202 ComPlex =_ Accordlna to U.S. 3,480,557 6 g. of PVP-CI (K-30) (GAF Corp.) (4.5% water) was dissolved in 50 ml. o~ methanol. Then 7 g. of a solution o~ H202 in water (50%) was added, followed by heating at 45C. for 2 hours, and evaporation o~ methanol for 12 hours. A gummy, amorphous residue was obtained which contained 12.92% H202 and 5% H20.

:

~ ~3 ~

Stabilitv of Anhydrous ComPlex of Example 1 After 43 days at 60C. the complex lo~t only 15%
of its H2O2 activity, which shows excellent stability toward decomposition. At room temperature, decomposition was only 1.5% after 60 days.

Preparation of Free-Flowing, Fine, White Powders of PVP-H202 ComPlex PVP-CI (K-30) (GAF Corporation) (4.S% water) was dried at 105C. in vacuo for 2 hours until it con~ained only 1.1% water. 160 g. of the dried, water-insoluble PVP
was suspended in 450 g. of anhydrous ethyl acetate (0.01%
water), and the suspension was cooled to 5-10C. while agitating the suspension. Then 55 ml. of 70% hydrogen peroxide solution in water (71 g. H202) was added 810wly over a period of 35 minutes to the agitated suspension keeping the temperature at 5-10C. A fine, white precipitate was ~ormed which was filtered to yield 312 g. o~ a wet product which was dried at 40-50C. in vacuo for 4 hours. 200 g. of a free-flowing fine, white powder was obtained which contained 19.5% H202 and 2.9%
water. Further drying under the same conditions for an additional 6 hour~ reduced the water content to 0.5% while maintaining the H202 content at 18.5% and without a~ecting the physical properties of the powder.
In the drying step above, 77.9 g. of mostly ethyl acetate was collected in the vacuum trap which also contained 0.2% H202 and 3.78% water in the upper layer and 8.0 g. of mostly water (92%) with 0.63% H202.

r ~

The filtrate (363 g.) obtained above contained 2.75% H202 and 1.54% H20, the rest being ethyl acetate, which was recycled as described in Example 2 below.

The procedure of Example 6 is followed using PVP-CI 160 g.; ethylacetate 450 g.; and 85% H202 56 g.
lg7 g. of a PVP-H202 complex with 19.2% H2O2 containing 1.56% H20 is obtained. Further drying at 40-50C. in vacuo will reduce the water content to 0.5%
H20 .

Preparation of Free-Flowing, Fine, White Powders of PVP-H~0 ComPlex bv RecYclinq the Filtrate of Example 1 To the filtrate from Example 6, 363 g., was added 90 g. of ~resh, anhydrous ethyl acetate followed by cooling to 5-10C. Then 170 g. oi dried PVP-CI was added at once whereupon the exothermic reaction increased the temperature to 12C. The suspension was cooled to 5C. with an ice-water bath. Then 58 g. of a 70% H202 solution was added over a period of 2 hours with good agitation. a fine, white precipitate was ~ormed and filtered to provide 320 g. of a wet cake which was dried at 40-500C. under vacuo for 4 hours to yield 202 g. of a free-flowing, fine, white powder containing 18.9% H202 and 3.1% H20.
Further drying under the same conditions ~or an additional 6 hours lowered the water content to 0.6%, and the H202 content to 18.3%, without a~fecting the physical characteristics of the powder.

~ ~3~

_ g _ The filtrate weighed 358 g., and was mostly ethyl acetate with 2.58% H202 and 1.49% water.

Preparation of Aqueous PVP-H202 Complex accordinq to U.S. 3,480,55_ To 6 ~. of PYP-CI (K-30) (GAF Corporation) (4.5%
water) was dissolved in 50 ml. of methanol was added 7 g.
of a solution of H202 in water (50%), followed by heating at 45C. for 2 hours, and evaporation of methanol for 12 hours. The gummy, amorphous residue contained 12.92% H202 and 5% H20.

Stability of Anhvdrous ComPlex of ExamPle 6 After 43 days at 60C. the complex lost only 15%
of its H202 activity, which shows excellent stability toward decompos~tion. At room temperature, decomposition was only 1.5% after 60 days.

.

Stability of Aqueous Solutions of AnhYdrous Complex of ExamPle 6 An aqueous solution of the complex of Example 6 containing 3.75% H20 was heated at 58C. for 96 hours.
At ~he end of this period, the solution analyzed for 2.75%
H20, which indicated excellent stability ~or aqueous solutions o~ the complex of the invention.

_ Stability of Aqueous Solutions of (a) Urea/H2_2 and (b) H22-(a) Under the same conditions as in Example 10, a urea/H202 solution, after only 36 hours, was reduced in H202 content from 3.5% to 0.6% H202. (b) An H202 solution itself lost all of its 3.0% H2O2 content after 36 hours.

Antimicrobial formulations of the complexe~ of the invention are prepared using a microbiocidal amount of the substantially anhydrous PVP-H202 complex, and an acceptable diluent and/or other active and inactive ingredient~ in the form of a suspension, solution, dispersion gel, powder, paste, suppository, aerosol, ointment, tablet, etc. The formulation may also be impregnated into or applied onto a suitable support, ~uch as a gauze, cotton swab, sponge, etc. Generally, the complex will be activated by water present on the sur~ace containing the microbes, the water functioning to release the active H202 ~rom the complex.

~ ~ a~ ,? ~ ~ ~3 .,~

VAGINAL SUPPOSITORY

Inqredient Percent Wt.
Anhydrous PVP-H202 14.29 0.3000 (23.1%)(Ex.l) Nonoxynol-9 4.76 0.1000 Amphoteric-19 1.71 0.0360 Povidone 4.29 O.O9oo Citric acid, anhydrous1.93 0.0405 Sodium bicarbonate 3.21 0.0675 Polyethylene glycol 1000 66.43 1.3950 Polyethylene glycol lS40 3.38 0.0710 100.00% 2.100 The suppository dissolves completely in about 1 ml of water in about 10 minutes at a temperature of about 37C. Upon contact with water, a slight development o~
~oam starts with simultaneous dissolution of the suppository. The ~oam development increases constantly until the dissolution is complete. The foam which ~orms has fine pores, is even and remains as such over an extended period of time. The nonoxynol-9 is a spermaticide, and the amphoteric-19 and PVP-peroxide are microbiocides.

EFFERVESCENT_NOUTHWASH TABLET

Inqredient Percent Wt. ~qrams) Anhydrous PVP-H202 27.29 0.122 (23-1%) (Ex.l) Sodium bicarbonate (granular)22.4 0.100 Sodium carbonate, anhydrous 2.24 0.010 Citric acid, anhydrous (granular) 44.74 0.200 Aminoacetic acid 1.79 0.008 Flavorants (spray dried) 1.11 0.005 Color 0.22 . 0.00L
Sodium benzoate (fine powder)0.22 0.001 100% 447 mg.

The tablets are compressed with 3/4 -in. diameter, ~lat-faced, bevel-edge tooling. The tablet ingredients, other than the anhydrous PVP-peroxide complex, are mixed, lightly dampened, and granulated. To the slightly dampened granules the anhydrous PVP-peroxide complex is added, and the well-mixed, slightly moi6t ingredients are compressed, then immediately thereafter placed in a 70C. ~orced draft oven ~or 1 hour to drive o~ any residual water. The cooled tablets are immediately packaged in air tight aluminum ~oil pouches.
The tablets are added to 60 cc (2 oz.) o~ water ~or use as an effervescent mouthwash and gargle.

:.

NON-AQUEOUS OINTMENT

Inqredient Percent wt.(q.) Anhydrous PVP-H2O2 15 150 (23%) (Ex.l) Sorbitan Monopalmitate 1 10 (Span 40-Atlas) Polyethylene Glycol 400 14 140 Monostearate Polyethylene Glycol 400 35 350 Polyethylene Glycol 4,000 35 350 100% l,000 g.

The polyethylene glycols and the sorbitan monopalmitate are warmed on a water bath to 70C. and the complex is added to the well-stirred molten mass. Stirring 1~ continued until the ointment is well-solidified.

ANTIBACTERIAL LIPSTICK

Inaredient Percent Wt. (q.~
Anhydrous PVP-H2O2 15 0.30 (23%) (Ex. 1) Polyethylene glycol 1000 17 0.34 Polyethylene glycol 4000 68 1.36 100% 2.00 g.

~he formulation is prepared as in 3 above.

POLYETHYLENE GLYCOL-CONTAINING OINTMENT

Ingredient Percent Wt.(q.) Anhydrous PVP-H2O2 15.17 21 (23%) (Ex. 1) Sodium Carbonate 5.06 7 Polyethylene Glycol 4000 36.13 50 Polyethylene Glycol 400 43.64 60.4 100% 138.4 g.

Heat the polyethylene glycol 4000 and 400 with -constant stirring on a water bath at 65C. Slowly add the micronized anhydrous sodium carbonate and PVP-H2O2 complex with constant stirrinq. Cool until the mass is well mixed and congealed.

ANHYDROUS TOOTHPASTE

No. Phase Inqredient % bY Wt.
1 E Anhydrous PVP-Hydrogen Peroxide (23~) (Ex. 1) 15 2 A Glycerin 10 3 A Xanthum Gum 0.25 4 B Polyethylene Glycol 400 47 C Thixcin 0.25 6 C Povidone K-90 0.5 7 D Monosodium Phosphate 0.7 8 D Trisodium Phosphate 1.25 g D Sodium Saccharin 0.2 D Sodium Fluoride 0~25 11 D Abrasive Silica 15 12 D Thickening Silica 6.6 13 D Titaniunm Dioxide 0.5 14 D Sodium Lauryl Sulfate 1.2 E Flavor Oil 1.2 16 E Pigment 0.1 100. 0%

All D items in formula above should be micropulverized and blended. Sprinkle the xanthum gum into glycerin with constant agitation until uniform (Phase A).
Add the polyethylene glycol 400 (Phase B) to Phase A with continued agitation. Sprinkle in Povidone K-90 until uni~orm and with constant stirring add the well mixed micronized ingredients of Phase D. Seal unit with cover and apply Z8 or more inches of vacuum for 30-45 minutes with continuous agitation. Add all ingredients o~ phase E, starting with the hydrogen peroxide complex (item 1), under continued agitation and mix until uniform. Mix under vacuum (28 inches or more) for 5 additional minutes.

TOOTH POWDER

Inqredient Percent wt. (qrams~
Anhydrous PVP-H202 15.0 15.0 (23%3 (~x. 1) Calcium Sulfate 52.35 52.35 Dicalcium Phosphate 27.0 27.0 Povidone K-90 1.5 1.5 Sodium Saccharin 0.15 0.15 Sodium Lauryl Sulfate 3.0 3.0 Flavor 1.0 1.0 100% 100 grams MEDICATED BANDAGE

Inqredient Percent Wt.(q.) Anhydrous PVP-H202 14.3 100 (23%) (Ex. 1) Povidone K-90 85.7 600 100% 700 g.

Blend micronized powders of the above two ingredients until homogeneous. Add ethyl alcohol to the well blended powder until a thick homogeneous paste is achieved. Lay a homogeneous layer of 700 mg plus the ethyl alcohol used for dispersion on 1 s~. inch of bandage.
Place the coated bandage material under vacuum and heat until the ethyl alcohol is completely evaporated. The resultant mixture of the H202 complex and povidone K-90, evenly spread on 1 square inch of bandagQ will yield about 3~ of available H202 from the solid povidon~
mixture.

-J~

If substantive microbicide activity is desired, 0.1% of cetyl pyridinium chloride can be mixed into the above blend before evaporation of the ethyl alcohol.

EAR DROPS SOLUTION

Ingredient Percent Wt.(g.) Anhydrous PVP-H2O2 6.5 6.5 (23%) (Ex. l) Anhydrous glycerol 93.5 93.5 100% 100q.

SOFT LENS DISINFECTION TABLET

Inqrzdient Percent Wt.(g.) Anhydrous PVP-H202 81.5 1.50 (23%) (Ex~ 1) Sodium bicarbonate (granular) 5.4 0.10 Sodium carbonate, anhydrous 0.6 0.01 Cltric acid, anhydrous granular 10.8 0.20 Sodium benzoate (fine powder)1.7 0.03 100% 1.84 g.

The tablet ingredients, other than the anhydrous PVP-H2O2 and sodium benzoate are mixed, lightly dampened to ~orm a damp granule. To the slightly dampened granules the povidone peroxide and sodium benzoate are added so that granules with a damp feel are compressed using l-l/4" flat-faced, bevel-edge punches. Immediately t ~ ~i e pl~

after compression the damp tablets are placed in a 70C.
forced draft oven for 1 hour to drive off any residual water. The cooled tablets are immediately packaged in air-tight aluminum foil pouches.

MEDICATED POWDER

Inaredient A ~ C
PVP K-30-H202 (6.47%) 10 50 60 (Soluble PVP) PVP-Cro~povidone-H202 10 1 5 (23.67%) (Insoluble PVP) Talc 60 45 30 Polyplasdone- XL10 10 4 5 H2O2 Activity 3% 3.5% 5.0 The above powders were mixed together to provide tho desired composition.

WOUND DRESSING
. .

Inqredient Percent Wt. (q.
Anhydrous PVP-H202 10 10 (22.8% H202) Absolute Ethanol 90 90 100% 100 g.

- .
' .
~-,, 3 ~ ~

A 1% H2O2 solution of the above composition is applied to a wound. A film is foxmed which is effective to disinfect the wound.

COLD WATER LAUNDRY TABLET

Inqredient Percent Wt. (g.) PVP-H2O2 (23%) (Ex. 1) 81.5 1.50 Sodium benzoate (fine powder) 1.64 0.03 100% 1.84 g.

These anhydrous PVP-H2O2 tablets are an ef~ective cold water bleach-disinfectant for cleaning clothe~, etc. In use, the PVP portion of the complex can chelate with inorganic ions (e.g. Ca++, Mg++) in the water to reduce water hardness. It can also provide laundry detergents with the properties of antiredeposition or suspension o~ dirt, anti-dye transfer, along with its bleaching and disin~ectant action.

WATER DISINFECTANT TABLET

Inqredient Percent Wt. (q.) Sodium bicarbonate 6.3 0.10 Sodium carbonate, anhydrous0.6 0.01 Citric Acid, anhydrous granules 12.6 0.20 Povidone-H2O2 (20~) 78.6 1.25 Sodium benzoate (fine powder) 1.9 0.03 100.0% 1.59 g.

~ ~ 2 ~

This tablet should be dissolved in one quart of water and allowed to remain for 5 minutes after the tablet i8 dissolved before the water is ready to drink. To prepare the tablet, follow the same direct$ons as given in Formulation 10 except use a 1 inch flat-faced, bevel-edge punch.
The above formulations and applications illustrate method~ of reducinq the bacterial content of surfaces using the anhydrous PVP-H2O2 complex of the invention.

, .
. . : .
., ., .-.

, , '. . . : ' ' ' ' ~

".. :.
,. , ~

Claims

1. A stable complex of PVP and H2O2 in a molar ratio of between about 2:1 and about 1:1, respectively, which is obtained as a uniform free-flowing, fine, white powder by direct reaction between suspended PVP
and H2O2 in substantially the molar ratio predetermined for the complex.

2. A complex according to claim 1 wherein the complex contains essentially little or no water or free hydrogen peroxide therein.

3. A process of preparing a stable, uniform free-flowing powder complex of PVP and H2O2 which comprising suspending PVP powders in an anhydrous medium and reacting H2O2 therewith.

4. A process according to claim 2 wherein the H2O2 is reacted in substantially the same molar ratio as desired in the complex.

5. A process according to claim 3 in which PVP is suspended in anhydrous ethyl acetate.

6. A suspension process for preparing uniform, free-flowing fine, white powders of a substantially anhydrous complex of PVP and H2O2 having an H2O2 content between about 18 and about 22% H2O which comprises:

(a) forming a suspension of water-insoluble PVP
containing less than about 1% water in an anhydrous organic solvent, (b) slowly adding a predetermined amount relative to the PVP of an aqueous H2O2 solution containing about 70 to about 85% by weight H2O2, at a temperature of about 0°-10°C. under agitation to precipitate a PVP-H2O2 complex in the form of a uniform, free-flowing, fine, white powder, (c) filtering, and (d) drying the wet precipitate to form the desired powders.

7. A suspension process according to claim 6 wherein said organic solvent is anhydrous ethyl acetate.

8. A process according to claim 6 wherein the filtrate is recycled for use in step (a).

9. A process according to claim 6 wherein drying is carried out at about 50°-60°C. in vacuo.

10. A method for reducing the microbial content of surfaces which comprises contacting said surface with a microbiocidal amount of a substantially anhydrous complex of PVP and H2O2 in the form of a free-flowing powder having an H2O2 content of about 3 to 24% by weight, wherein said complex is present in a formulation in an amount of about 0.1 to 15% by weight.

11. A method according to claim 10 wherein said complex is present on a support.

12. A method according to claim 11 wherein said support is a gauze, cotton swab or sponge.

13. A method according to claim 10 wherein said complex is present in a non-aqueous formulation.

14. A method according to claim 10 wherein said surface comes into contact with living tissue.

15. A formulation for reducing the microbial content of surfaces which include a microbiocidal amount of an anhydrous PVP and H2O2 complex, having an H2O2 content of about 3 to 24% by weight.

16. A method according to claim 1 further characterized in that said surface is contacted in the presence of water.

17. A formulation according to claim 16 wherein the complex has a molar ratio of PVP and H2O2 between about 2:1 and about 1:1.

18. A formulation according to claim 16 which also includes one or more of an acceptable diluent, and an active or inactive ingredient.

19. A formulation according to claim 16 which is in the form of a suspension, solution, suppository, gel, powder, paste, ointment, or tablet, optionally, on a support.

20. A formulation according to claim 16 which is a non-aqueous composition.

21. A formulation according to claim 16 which is a vaginal suppository, an effervescent mouthwash, a non-aqueous ointment, a polyethylene glycol-containing ointment, an anhydrous toothpaste, a tooth powder, a medicated bandage, an ear drop solution, a soft lens disinfectant tablet, a medicated powder, a wound dressing, a cold water laundry tablet, or a water disinfectant tablet.