Cleaning and liquid contact with solids – Processes – Combined
Reexamination Certificate
2000-09-08
2003-10-14
Markoff, Alexander (Department: 1746)
Cleaning and liquid contact with solids
Processes
Combined
C134S026000
Reexamination Certificate
active
06632290
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the cleaning arts. It finds particular application in conjunction with the detection of residual cleaning products remaining on pharmaceutical processing equipment after cleaning, and will be described with particular reference thereto. It should be appreciated, however, that the invention is also applicable to a variety of cleaning applications where it is desirable to ensure that the cleaning product has been thoroughly removed before reuse of the equipment.
Industries such as the pharmaceutical industry clean tanks and other processing equipment with detergent-based cleaners to remove traces of the products processed in the equipment. For pharmaceutical applications, in particular, it is important to ensure that the cleaning process has effectively removed drugs and cleaning product residues from the equipment so that there will be no cross contamination from one batch of the product to another and therefore no physiological impact. The Food and Drug Administration requires that tests be conducted to validate the cleaning process.
The level of residual cleaning product remaining on the equipment after cleaning is commonly determined by a non-specific analytical method, such as Total Organic Carbon (TOC) analysis. This approach is limited in that it only offers information about the water-soluble carbon content of all components in the residue and not about specific components in the cleaning product.
Currently, High Performance Liquid Chromatography (HPLC) is the method of choice for determining the level of residual pharmaceutical product on the equipment. The HPLC device is calibrated using a sample of one or more of the drug additives processed in the pharmaceutical equipment. A sample of residue extracted from a wall of the processing tank, or other part of the equipment, is compared with the calibrated sample and the remaining level of pharmaceutical residue determined.
The HPLC technique is a highly sensitive method of detecting specific components in the residue. However, the technique has not been used for detecting traces of the cleaning product on the equipment. Most components of cleaning products do not contain a detectable species, or chromophore, which can be detected by the HPLC. Moreover conventional surfactants used in the cleaning products tend to degrade over time due to the highly alkaline or acidic pH of the cleaning product and thus are not capable of acting as stable indicators for the cleaning product.
The present invention provides a new and improved cleaning composition and method for detection of residual cleaning composition after cleaning which overcomes the above-referenced problems and others.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, a method of evaluating a surface for removal of a cleaning composition after a cleaning process, the cleaning composition including a detectable substance which is stable in the cleaning composition is provided. The method includes rinsing the surface to produce a rinsate which contains the detectable substance and analyzing the rinsate for the detectable substance to provide an indication of whether the cleaning composition has been removed from the surface to at least a maximum acceptable level.
In accordance with another aspect of the present invention, a cleaning composition for cleaning a residue from a surface is provided. The composition includes a detectable substance which is stable in the cleaning composition and which is detectable at a concentration of about 10 ppm or less.
In accordance with another aspect of the present invention, a cleaning composition for cleaning a residue from a surface is provided. The composition includes, in terms of weight percent:
an anti-redeposition agent
1-10;
a strong alkali
9-50;
a chelating agent
1.0-10.0;
a surfactant
0.2-5; and
water
Q.S.
The surfactant is one which is detectable at a concentration of 10 ppm or below for serving as an indicator of whether the cleaning product has been removed from the surface.
In accordance with another aspect of the present invention, a method for determining whether a piece of equipment has been rinsed sufficiently to remove a process residue and a cleaning composition used in cleaning the process residue from the equipment is provided. The method includes spectroscopically analyzing a rinsate from the equipment at a first selected wavelength to determine whether a preselected component of the process residue is above a minimum preselected level and spectroscopically analyzing the rinsate at a second selected wavelength to determine whether a spectroscopically detectable substance in the cleaning composition is above a minimum preselected level.
One advantage of the present invention is the provision of a cleaning composition which includes a detectable component for assessing whether the cleaning product has been thoroughly rinsed from the equipment being cleaned.
Another advantage of the present invention is that the detectable component may be detected by HPLC.
Yet another advantage of the present invention is that it enables residual cleaning product to be detected by the same method as is conventionally used for detecting pharmaceutical residues.
A further advantage of the present invention is the provision of a surfactant for a cleaning product which is detectable at extremely low levels and is stable at strong pH.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.
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patent: 4485028 (1984-11-01), King
patent: 5143562 (1992-09-01), Boulos
patent: 5279758 (1994-01-01), Choy
patent: 5858941 (1999-01-01), Oakes et al.
Material Safety Data/Fiche Signaletique: RHODAFAC BP-769; Rhone-Poulenc Canada, Inc. (1994).
T-MULZ Emulsifiers: T-MULZ 211; Harcros Organics (1995).
Formulation Science: vol. I, Proceedings from Formulations Forum '97 Edited by: Chester L. Foy, David W. Pritchard and George G. Beestman: Published by The Association of Formulation Chemists (1997).
Philip L. Robinson “C-21 Dicarboxylic Acids in Soap and Detergent Applications” JAOCS, vol. 69, No. 1, Jan. 1992.
Kaiser Herb J.
Keller Shahin
Shah Sayed Sadiq
Fay Sharpe Fagan Minnich & McKee LLP
Markoff Alexander
Steris Inc.
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