Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/40—Dyes ; Pigments
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/43—Solvents
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/48—Medical, disinfecting agents, disinfecting, antibacterial, germicidal or antimicrobial compositions

Definitions

• This invention relates to germicidal compositions, particularly for use on surfaces, ie compositions capable of destroying or inactivating micro-organisms, particularly surface-bound micro-organisms.
• the present invention provides a surface germicidal composition comprising a dyestuff which is capable of photo-dynamic inactivation of micro ⁇ organisms.
• a dyestuff that generates singlet oxygen on exposure to light. On absorption of light energy a dye molecule is converted to a more energetic or
• the excited state is short lived and can lose energy and return to the ground state in a number of ways: by emission of a quantum of light as fluoresecence; by internal conversion as the energy is degraded to heat; by collision with a molecule of a different substance (fluorescence quenching).
• the short lived singlet state may also undergo a process called intersystem crossing to a longer-lived excited state, the triplet state.
• the state is termed "triplet" because the electron in the higher energy level is no longer spin-paired with the electron in the lower level and the excited state has three energy levels in a magnetic field.
• Type II photo-oxidation Singlet oxygen is highly reactive and photosensitised oxidation proceeding via this route is known as Type II photo-oxidation.
• Type II photo-oxidation is independent of the photosensitiser used to generate the singlet oxygen.
• An important feature of the sensitiser is that it should have a high quantum yield of triplet formation (that is, ideally, a triplet state should be produced for each photon absorbed). Intersystem crossing to the triplet state is facilitated by the presence of heavy atoms in the molecule.
• Photo-oxidation of any vital component of an organism may result in cell death (protein, polypeptide, amino-acids, lipids with allylic hydrogens, tocopherols, sugars and cellulose) .
• Currently preferred dystuffs include Rose Bengal (Acid Red 94, Colour Index No. 45440), Erythrosin B (Acid Red 51, Colour Index No. 45430), and phthalocyanin sulphonates ⁇ - such as aluminium phthalocyanin sulphonate (APS) and -zinc phthalocyanin sulphonate (ZPS) .
• Rose Bengal and Erythrosin B are " known food colourants (Rose Bengal is ⁇ - Food Colour Red No 105 and Erythrosin B is Food Colour Red No 14), and Erythrosin B is on an EEC list of colouring agents allowed for use in cosmetic products, so these two dyes are well suited for use in compositions intended for domestic use. Mixtures of dyes can be used, and in some cases it may be desirable to include in a mixture a dye that will remain visible at the end of the photodynamic process.
• concentration of dyestuff in the composition is not critical and will typically be up to lOOppm, with good results having been obtained with concentrations in the range lOppm to 20ppm. Lower concentrations, down to lppm should also give reasonable results.
• Singlet oxygen has a short lifetime and therefore a short pathlength for diffusion, so to be effective a photosensitising dye generating singlet oxygen must be close to the target substrate.
• Preferred dyestuffs are therefore substantive to (ie capable of binding to) micro ⁇ organisms, typically by binding to cellular protein on the organism surface or other cellular components eg cellular fats.
• the preferred dyes mentioned above generate -singlet oxygen on exposure to light and are substantive to protein and so capable of binding to micro-organisms via cellular protein. In this way, targetted killing of organisms and hence germicidal action is possible.
• a dyestuff that is bleached by exposure to light.
• a photo-bleaching dyestuff that is substantive to micro-organisms it can be possible for a visible indication of the presence of micro ⁇ organisms to be provided.
• the photo-dynamic action proceeds causing the death of, or otherwise inactivating, micro-organisms.
• both bleaching and the photo- dynamic activity are believed to proceed more slowly, whereas at higher light intensities both processes occur more quickly.
• the presence of visible dyestuff indicates to the user that the photo- dynamic inactivation of any micro-organisms present is incomplete.
• micro-organisms are much more susceptible to biocides in their planktonic or suspended state: they are much more difficult to inactivate when attached to surfaces, which is their usual or preferred state.
• Micro-organisms will normally be on surfaces in the form of "biofilms", that is, embedded in a matrix of extracellular material. This extracellular material may sometimes be referred to as “adhesin” in the literature. It is therefore not obvious that a process which acts on micro-organisms in their planktonic state would act on surface-bound organisms without modification being required.
• Surface-bound micro ⁇ organisms represent an important and substantial source of contamination in domestic, institutional and industrial environments, and the present invention can enable targetted germicidal action on such micro-organisms.
• compositions according to the present invention are particularly suitable for use on hard domestic and industrial surfaces such as glass, plast cs, ceramic and metal surfaces.
• the c positions are effective for use on surfaces which may aarbour soils having the potential for bacteriological contamination in surface imperfections, joints and otr- relatively confined regions.
• the composition is preferably acidic, eg having a pH in the range of 3 to 5, eg a pH of about 4, as acidic compositions are found to have substantially enhanced effectiveness against Gram-negative (G-) micro-organisms as compared with neutral compositions.
• G- Gram-negative
• G+ Gram-positive
• the compositions are conveniently made acidic by use of relatively mild organic acid, such as acetic acid.
• the composition may optionally include other ingredients such as one or more surfactants (for cleaning purposes) and/or one or more solvents.
• the surfactant is preferably alkoxylated, more preferably ethoxylated, eg being in the form of ethoxylated alcohols.
• the alcohol preferably has between 4 and 15 carbon atoms, is of straight or branched chain configuration, and has an HLB value (hydrophilic lipophilic balance) in the range 10 to 14, eg 12.
• surfactants are commercially available, one such material being the surfactant available under the trade name Imbentin 91-35, from Kolb, which is a nonionic C9-11 alcohol ethoxylate, having an average of 5 moles of ethylene oxide per mole of alcohol.
• Primary ethoxy sulphates may also be used.
• Mixtures of surfactants may be used if desired.
• the surfactant is preferably non-ionic or anionic, or a mixture of both types.
• Preferred anionic surfactants for this purpose include primary alkyl sulphates (PAS) , preferably sodium dodecyl sulphate (SDS).
• PAS primary alkyl sulphates
• SDS sodium dodecyl sulphate
• Commercial mixtures containing a substantial proportion of dodecyl sulphate eg Empicol LX are espcially preferred.
• Dodecyl sulphate is a known protein denaturant, is good for cleaning protein off surfaces, and is biocidal.
• composition is preferably substantially free of cationic surfactant, but may include a minor amount of cationic germicide.
• Surfactant preferably constitutes an amount in the range 0.05 to 2.5% by weight of the total weight of the composition, typically 0.5% to 1.5% by weight, eg 0.7% by weight nonionic surfactant with an optional amount of up to 0.2% by weight of anionic surfactant.
• the solvent is preferably polar and is preferably a straight or branched chain C2 to C5 alcohol such as ethanol, butanol, isopropanol (propan-2-ol) (IPA), N- butoxy propan-2-ol (propylene glycol n-butyl ether), 2- butoxy ethanol (ethylene glycol onobutyl ether).
• IPA is the currently preferred solvent.
• Dihydric alcohol such as ethylene glycol
• water miscible ethers such as dimethoxyethane may also be used.
• Mixtures of solvents can be used if appropriate, eg mixtures of ethanol and N-butoxy propan-2-ol.
• Solvent is preferably present in an amount in the range 2 to 20% by weight of the total weight of the composition.
• the present invention thus provides a surface cleaning and germicidal composition, comprising a dyestuff which is capable of photo-dynamic inactivation of micro-organisms, a surfactant and a solvent.
• composition may include a number of optional ingredients including the following:
• Detergent boosters preferably metal chelating agents such as ethylene diamine tetra acetic acid (EDTA) .
• Metal chelating agents include EDTA have also been claimed to permeabilise cell walls, thus making organisms more susceptible to biocides.
• Electrolyte such as a buffer or salt, eg Na SO , which acts to assist binding of dye to protein by promoting movement of dye from the aqueous phase to the protein salt. Electrolyte is commonly present in various dye formulations as commercially available, although additional electrolyte can be added if required. Total electrolyte content of the composition would typically be in the range 0 to 1% by weight, preferably about 0.1%.
• the composition is in the form of an isotropic, single phase composition and is of particular use as a germicide (possibly also with a cleaning effect) on hard surfaces, finding application in a wide range of contexts, including domestic applications, eg kitchen and bathroom surfaces including toilet bowls, in institutions such as schools, hospitals etc, and in commercial premises such as factories, offices, hotels etc.
• the composition is preferably formulated as a product intended for application by spraying and is conveniently packaged in a suitable container, eg having a hand operated trigger spray or an aerosol propellant dispenser.
• a suitable container eg having a hand operated trigger spray or an aerosol propellant dispenser.
• the container is preferably light-opaque.
• the composition is applied to a surface to be treated in any convenient manner, eg by spraying from a suitable dispenser, wiping on with a carrier such as a cloth or sponge, or pouring from a container etc.
• a light source eg a white light source such as a quartz halogen lamp or fluorescent "daylight” source.
• the process would be an alternative to using dangerous germicidal radiation, for example from a low pressure mercury discharge lamp emitting resonance radiation at 254 nm. Such radiation is harmful to the unprotected eye.
• This would generally be followed by a rinsing step, if required, eg by wiping with a carrier, application of a stream of running water etc.
• the invention thus provides a method of killing bacteria on a surface, comprising applying to the surface a composition in accordance with the invention.
• Figure 1 shows two bar charts of log (reduction) values illustrating the lethal effect of Rose Bengal and light on various micro-organisms in suspension at pH4 and pH7, with Figure la showing results for Gram-positive micro ⁇ organisms, and Figure lb showing results for Gram-negative organisms and yeasts;
• Figure 2 is a pair of graphs of log (reduction) versus pH showing the biocidal effect of Rose Bengal and light on S. aureus and E. coli as a function of pH, with Figure 2a showing results after 20 minutes exposure to light and Figure 2b showing results after 60 minutes exposure;
• Figure 3 is a pair of graphs similar to Figure 2 obtained using Erythrosin B in place of Rose Bengal;
• Figure 4 shows two bar charts of log (reduction) illustrating the photohygiene effect of various combinations of Rose Bengal (RB), Imbentin C91-35 (AE), isopropranol (IPA) and Empicol LX (PAS), with Figure 4a showing results obtained without exposure to light and Figure 4b showing results obtained with exposure to light;
• RB Rose Bengal
• AE Imbentin C91-35
• IPA isopropranol
• PAS Empicol LX
• Figure 5 is a graph of adsorption of Rose Bengal by E. coli, with amount adsorbed (nanomoles) versus equilibrium concentration (micromoles/l) , with results at pH 4 shown by squares and results at pH 7 shown by crosses;
• Figure 6 is a pair of graphs similar to Figure 5 showing the effect of electrolyte, with Figure 6a showing results at pH 4 and Figure 6b showing results at pH 7, with results without additive shown by squares, results with sodium sulphate (1%) shown by crosses and results with sodium sulphate (5%) shown by double crosses;
• Figure 7 is a pair of graphs similar to Figure 5 showing the effect of surfactant, with Figure 7a showing results at pH 4 and Figure 7b showing results at pH 7, with results without additive shown by squares, results with non-ionic surfactant (0.7%) (NI) shown by crosses and results with PAS (0.7%) shown by double crosses;
• Figure 8 is a graph similar to Figure 5 showing the effect of solvent at pH 4, with results without additive shown by small squares, those for 10% IPA shown by crosses, those for 0.7% Imbentin shown by double crosses and those for 10% IPA and 0.7% Imbentin shown by large squares;
• Figure 9 is a graph of log (reduction) versus exposure time (minutes) showing the effectof pH on the rate of kill of E. coli by Rose Bengal, with results at pH 4 shown by squares and results at pH 7 shown by crosses; and
• Figure 10 is a graph similar to Figure 9 showing the effect of electrolyte at pH 7 on the rate of kill of E.coli by Rose Bengal, with results without electrolyte shown by squares and results with Na sulphate shown by crosses.
• Klebsiella sp. ATCC 11677 (Gram negative)
• Organisms were grown up by overnight incubation in nutrient broth at 37 ⁇ C for bacteria (28°C for Ps. aeruginosa) or SABS broth (SABS is Sabourand Dextrose Agar, with liquid medium in the case of SABS broth, from Oxoid Ltd) at 28 ⁇ C for yeast. Cultures were isolated by vacuum filtration using a 0.45um Millipore filter and washed with quarter-strength Ringers solution before resuspension in Ringers solution (10ml).
• the organisms in suspension were enumerated by serial dilution and plating with nutrient agar (bacteria) or SABS agar (yeast) and the total viable count (TVC) expressed as the decadic logarithm of the number of colony-forming units (cfu) per ml.
• Aqueous solutions containing 100 ppm of dye were prepared. Aliquots (10ml) of each dye solution were sterilized in glass universal screw cap vials. Antibiotic assay discs (13mm from BDH) were also sterilized. All organisms were grown overnight in nutrient or SABS broth (10ml).
• SABS agar for the yeast For each micro-organism, two nutrient agar plates (SABS agar for the yeast) were seeded with the overnight culture (10ul) to give confluent growth over the whole plate. Using aseptic techniques, an antibiotic disc was dipped into the first dye solution and placed on the surface of a seeded agar plate. This was repeated with two other dye solutions to give three discs on duplicate plates.
• Results on agar for aqueous dye solutions of Rose Bengal, Erythrosin B and aluminium phthalocyanin sulphonate (APS) (100 ppm) at pH 7 after exposure to light for 180 minutes as described above are summarised in Table 1.
• the results are expressed as the difference (in millimetres) between the radius of the clear zone of inhibition (the area of no bacterial growth on the spread agar plate) and the radius of the disc.
• the higher the value the greater the baterial kill.
• the agar diffusion disc method ranked Rose Bengal as more effective than the structurally similar Erythrosin B. It is plausible to ascribe this ranking to a difference in the quantum yield for singlet oxygen formation. In methanol, the quantum yield for singlet oxygen formation is 0.76 for Rose Bengal compared to 0.6 for Erythrosin B. However, a number of other factors might also be expected to contribute to the observed differences such as the rate of dye diffusion or differences in dye binding to the agar gel or disc material.
• Sodium hypochlorite solution (0.125 %) was used as a positive control.
• Micro-organism, eg S. aureus, suspension (0.5ml) was added to aliquots (100 ml) of quarter-strength Ringers solution and the average cfu per ml determined (TVC). Aliquots (20ml) of these solutions were pipetted into sterile petri dishes and left at room temperature for 5 hours. The inoculum was then removed by pipette into a sterile bottle and the average cfu per ml remaining in suspension estimated. The number of organisms (as cfu) per square era adherent to the Petri dish was calculated from the difference in the solution concentrations.
• one of the duplicate plates was overlaid with Tryptone Soya agar containing 1% glucose and 0.015% Neutral Red cooled to about 50°C.
• the other duplicate plate was stained with 0.01% Acridine Orange for 30 seconds, rinsed and examined microscopically (Nikon "Optiphot" microscope equipped with a 100x apochromat oil- immersion objective, 10x eyepiece and epifluorescence attachment with a B2-A combined filter/dichroic mirror block and super high pressure mercury lamp) .
• the overlaid agar plates were incubated at 3 ' X for 48 hours, by which time colonies had grown out of the adherent bacteria wh. :h had not been killed.
• Example 2 Control experiment surface tests usi : Bg ⁇ c -both direct epifluorescence microscopy as described above and suspension depletion gave similar values for the number of bacteria (S. aureus) that could be attached to the surface of a plastic dish (of the order of one million per square centimetre) .
• Anionic surfactant (Empicol LX, 14 percent) (sometimes referred to as PAS) pH 4 buffer (citric acid (0.1 M,307 ml) + dibasic sodium phosphate (0.2 M, 193 ml) pi 7 buffer (sodium dihydrogen orthophosphate (0.4M,468 ml) + disodium hydrogen orthophosphate dodecahydrate, (0.4M,732 ml)
• Test solutions were made up in sterile plastic petri dishes to a depth of 5mm (30mls). A suspension of micro ⁇ organism (0.3ml) was added to each solution and gently mixed in. If Rose Bengal was to be included in the test solution it was added last to minimise light exposure. Solutions were either exposed on a light box, placed in the dark (conditions of reduced light exposure) or left on the bench. The average intensity at the surface of the light box diffuser was 4000 lux measured with a Megatron DA 10 light meter (from Megatron Ltd). After specified exposure times, surviving bacteria were enumerated as colony-forming units (cfu/ml) following incubation after serial dilution and plating onto agar. The decadic logarithm of the number of bacteria remaining (as colony- forming units per ml) was determined and compared to the number before exposure as log (start count) - log (final count). The higher the value, the greater the bacterial kill.
• Results obtained in similar manner for E. coli at pH 7 are shown graphically in the bar charts of Figure 4.
• PAS is used as an abbreviation for Empicol LX
• IPA is used as an abbreviation for isopropanol
• AE is an abbreviation for Imbentin C91-35. This figure represents averaged data for AE 0.7%, PAS 0.7%, IPA 10%.
• Examples 9, 10, 11 and 12 used the Gram positive organism S. aureus, and Examples 13 and 14 the Gram negative organism E. coli. Other reagents used are indicated in the examples. In all these Examples, samples were exposed for 20 minutes on a light box. The average intensity at the ⁇ surface of the diffuser was 4000 lux measured with a Megatron DA10 light meter (from Megatron Ltd).
• Lialet 111 is the trade name of an ether sulphate formulation commercially available from Enichem, having an average chain length 11 with an average degree of ethoxylation of 3.
• the log (start) was 6.7. ' Results are given in Table 10.
• ⁇ ose Bengal adsorption was determined from the depletion in solution concentration. Concentrations were obtained spectroscopically from absorbances measured at the wavelength of maximum absorbance (ca. 549 nm) using a WPA Linton S110 spectrophotometer on supernatant liquors freed from microbes by centifugation.

Landscapes

• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)
• Detergent Compositions (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Apparatus For Disinfection Or Sterilisation (AREA)
• Measuring Or Testing Involving Enzymes Or Micro-Organisms (AREA)

Applications Claiming Priority (7)

Publications (2)

Family

ID=27266295

Family Applications (1)

Country Status (15)

Families Citing this family (20)

Family Cites Families (3)

• 1993
  • 1993-07-14 ES ES93916071T patent/ES2130276T3/es not_active Expired - Lifetime
  • 1993-07-14 KR KR1019950700238A patent/KR100252797B1/ko not_active IP Right Cessation
  • 1993-07-14 DE DE69324015T patent/DE69324015T2/de not_active Expired - Fee Related
  • 1993-07-14 CA CA002140896A patent/CA2140896A1/en not_active Abandoned
  • 1993-07-14 WO PCT/GB1993/001478 patent/WO1994002022A1/en active IP Right Grant
  • 1993-07-14 JP JP06504251A patent/JP3133336B2/ja not_active Expired - Fee Related
  • 1993-07-14 PL PL93307168A patent/PL173758B1/pl unknown
  • 1993-07-14 SK SK64-95A patent/SK6495A3/sk unknown
  • 1993-07-14 HU HU9500176A patent/HUT70688A/hu unknown
  • 1993-07-14 AU AU45774/93A patent/AU4577493A/en not_active Abandoned
  • 1993-07-14 BR BR9306767A patent/BR9306767A/pt not_active IP Right Cessation
  • 1993-07-14 CZ CZ95145A patent/CZ14595A3/cs unknown
  • 1993-07-14 EP EP93916071A patent/EP0652709B1/de not_active Expired - Lifetime
  • 1993-07-15 TW TW082105640A patent/TW272114B/zh active
  • 1993-07-22 CN CN93116562A patent/CN1086255A/zh active Pending

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events