Chemical apparatus and process disinfecting – deodorizing – preser – Process disinfecting – preserving – deodorizing – or sterilizing – Using disinfecting or sterilizing substance
Reexamination Certificate
2000-04-05
2003-05-13
Thornton, Krisanne (Department: 1744)
Chemical apparatus and process disinfecting, deodorizing, preser
Process disinfecting, preserving, deodorizing, or sterilizing
Using disinfecting or sterilizing substance
C134S002000, C134S003000, C134S039000, C134S041000, C134S042000, C422S001000, C422S034000, C510S203000, C510S206000, C510S210000
Reexamination Certificate
active
06562296
ABSTRACT:
The present invention relates to the use of a cleaning composition concentrate in particular for the mechanical cleaning of medical and/or surgical instruments and/or apparatuses and to a process for carrying out this cleaning.
Surgical instruments and other medical equipment are conventionally mechanically cleaned in the hospital using alkaline cleaning compositions and are then chemically or thermally disinfected. Such strongly alkaline media can act aggressively towards sensitive surfaces. Blood-contaminated surgical instruments are frequently deposited immediately after their use, for example, into an aldehyde-containing disinfectant solution and initially remain therein until they are cleared out into the dishwasher for cleaning. The blood is coagulated by the disinfectants and the protein constituents present in the blood are denatured by the aldehyde active disinfectant compound. Particularly persistent blood residues of this type may frequently only be removed by alkaline active-chlorine-containing cleaning compositions. The oxidizing active chlorine component causes the decomposition of the denatured protein constituents. Other constituents of disinfectants, for example iodine, can also form residues which are difficult to remove.
The alkaline active-chlorine-containing cleansers have the disadvantages that they comprise dangerous substances which are subject to declaration, that special safety precautions are necessary during their handling to protect the operating personnel and that they constitute an unwanted environmental pollution in the wastewater.
U.S. Pat. No 4,243,546, EP-A-0 481 663 and EP-A-0 730 024 disclose enzyme-containing cleaning compositions which can enzymatically degrade in particular blood proteins. It is proposed there to use triethanolamine for stabilizing the enzymes. Disadvantages of these cleansers are the high price of the enzymes, their heat sensitivity and the decay of the enzyme activity during relatively long storage, in particular at relatively high temperatures.
The object underlying the invention is to provide a process for cleaning medical and/or surgical instruments and/or apparatuses in which the disadvantages of the active-chlorine-containing and enzymatic cleansers do not occur or occur to a relatively small extent and which nevertheless ensures a sufficient cleaning action.
The invention achieves this object by the features of claims 1 and 13. Advantageous developments are specified in the subclaims.
The invention thus relates to the use of an enzyme-free cleaning composition concentrate which comprises at least 10% by weight of at least one alkanolamine for cleaning medical and/or surgical instruments and/or apparatuses.
Although alkanolamine-containing enzymatic cleansers are already known in the prior art, only an enzyme-stabilizing action is ascribed there to the alkanolamine (U.S. Pat. No. 4,243,546), and the actual cleaning agent is said to be the enzymatic active compound. Surprisingly, it has now been found, however, that an alkanolamine, as main active component of a cleaning composition, is suitable for complete removal from surgical instruments of blood residues which have dried on, been preheated or denatured by, for example, aldehyde active disinfectant compounds in the context of mechanical cleaning. The iodine residues and their reaction products with blood constituents which frequently originate from disinfectants are also removed. This cleaning action is obtained despite the omission of enzymes which are considered to be essential in the prior art.
Preferably, the alkanolamines used have the following structure:
where R
1
is a hydroxyalkyl group having 1 to 6 carbon atoms and R
2
and R
3
independently of one another are the said hydroxyalkyl group or hydrogen.
Particular preference is given to mono-, di- and/or triethanolamine.
The alkanolamines used according to the invention are bases. It is possible in the context of the invention to use the cleanser concentrate in aqueous solution in a pH range which is established by the presence of these bases and is generally above 9, preferably above 9.5. A pH of 10.5 to 11 is generally not exceeded. An alkaline cleanser of this type can require particular safety measures during handling. Sensitive surfaces (for example anodized aluminium surfaces) can under some circumstances be attacked by a more strongly alkaline cleanser. However, the aggressivity of the cleanser made alkaline according to the invention towards anodized aluminium surfaces is markedly decreased if this cleanser does not comprise a complexing agent such as NTA. Setting the pH alkaline is advantageous for complete removal of blood/iodine residues. This good cleaning action is achieved even in the absence of complexing agents such as NTA.
In a further embodiment of the invention the cleanser concentrate in ready-to-use dilute aqueous solution has a pH of 6 to 10, preferably 7 to 9. It has proved that surprisingly the alkanolamines which are alkaline per se develop a sufficient cleaning action even in this slightly acidic to slightly alkaline region. A ready-to-use dilution is taken to mean according to the invention a 0.5-100% strength aqueous solution of the cleaning composition concentrate. When in the context of the present application pHs of a dilute solution of the cleaning composition concentrate are measured, the solvent used is demineralized water. If the concentrate is made up with standard tap water to give a ready-to-use solution, slightly differing pHs can result depending on the properties of this water.
The pH is set to the said range preferably by addition of acids and/or suitable buffer systems. Preference is given to the addition of at least one organic acid selected from the group consisting of mono-, di- or tricarboxylic acids having 2 to 6 carbon atoms. Acids which are preferred among these are citric acid, tartaric acid, malic acid, lactic acid, glycolic acid, glyoxylic acid, succinic acid, adipic acid and glutaric acid. Citric acid is particularly preferred. The acids are added to the concentrate preferably in an amount of 0.5 to 15% by weight, more preferably 2 to 10% by weight.
According to the invention, the concentrate can comprise at least one complexing agent, in particular chelating agent. The complexing agents serve for water softening and, by complexing alkaline earth metal ions, can improve the cleaning action compared with lime soaps. The complexing agents can be homo-, co- or terpolymers based on acrylic acid or alkali metal salts thereof, in addition phosphonic acids or alkali metal salts thereof, such as, for example, 1-hydroxyethane-1,1-diphos-phonic acid, aminotrismethylenephosphonic acid, ethylenediaminotetrakismethylenephosphonic acid, phosphonobutanetricarboxylic acid; tartaric acid, citric acid and gluconic acid; and in addition nitrilotriacetic acid or ethylenediaminetetraacetic acid or salts thereof.
The concentrate of the invention can comprise nitrilotriacetic acid and/or a salt of this acid, particularly preferably its trisodium salt. This NTA addition surprisingly causes particularly good lime soap removal even at low pHs in the range 6 to 9. The NTA addition is additionally advantageous if the concentrate is to be made up to give a ready-to-use solution using (hard) water having a high mineral content.
If, owing to the necessity of using the cleanser with relatively hard water, the addition of complexing agents, such as, for example, NTA, is necessary, under some circumstances anodized aluminium surfaces can be attacked by the cleanser solution. Surprisingly, it has been found that the corrosive action of such complexing agents is decreased or avoided completely by the addition of at least one mono- and/or diester of phosphoric acid with aliphatic alcohols of chain length C
1
to C
22
and/or aliphatic diols and/or aliphatic polyols of chain length C
2
to C
22
. Particular preference is given to a diester of phosphoric acid with butanol on the one hand and ethylene glycol on the other hand. This ester is commercially available under the name Hordapho
Staffeldt Jürgen
Tiarks Petra
Chemische Fabrik Dr. Weigert GmbH & Co. KG
Medlen & Carroll, LLP.
Thornton Krisanne
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