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A Biological Menses Simulant Using a “Batch” Homogenization Process With Varying Levels of Rheological Properties

IP.com Disclosure Number: IPCOM000198395D
Publication Date: 2010-Aug-06

Publishing Venue

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Abstract

A biological menstrual test fluid, which is comprised of thick egg white from chicken eggs, porcine red blood cells and plasma, is representative of actual menses properties. The biological menstrual test fluid was previously produced using a “bag” type process which is outlined in US Patent #5,883,231. The fluid made with this method showed variability problems in various absorbent material performance tests. Additionally menses simulant does not currently represent the broad range of menses rheological properties that have been measured in collected menses samples. In light of repeatability issues, an alternative production method was devised which involves a larger “batch” type process. Additionally, in order to evaluate product performance at broader, more extreme rheological properties, a method to produce high viscosity menses simulant has been developed.

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A Biological Menses Simulant Using a “Batch” Homogenization Process With Varying Levels of Rheological Properties

Authors:  Jack Lindon, Brian Lin, Candee Krautkramer, Teuta Elshani, Aneshia Ridenhour

A biological menstrual test fluid, which is comprised of thick egg white from chicken eggs, porcine red blood cells and plasma, is representative of actual menses properties.  The biological menstrual test fluid was previously produced using a “bag” type process which is outlined in US Patent #5,883,231.  The fluid made with this method showed variability problems in various absorbent material performance tests.  Additionally menses simulant does not currently represent the broad range of menses rheological properties that have been measured in collected menses samples. In light of repeatability issues, an alternative production method was devised which involves a larger “batch” type process.  Additionally, in order to evaluate product performance at broader, more extreme rheological properties, a method to produce high viscosity menses simulant has been developed. 

This batch protocol is outlined in Appendix A.  The revised batch method produces fluid which significantly reduces variation seen in absorbent material performance tests.   The primary difference between the older “bag” process and the “batch” process is the way in which the plasma and thick egg white mixture is blended. The old process involved shearing the thick egg white through large syringes in order to homogenize it.  It was then mixed with the plasma using a Stomacher blender. The method now differs in that the syringes are no longer used to mix the thick egg white. Rather, 700 total mL of plasma and thick egg white are mixed together in a 1 L reaction vessel with a 2 inch diameter flat disc stirrer running at 1000 rpm for 1 hour. For a detailed description of the fluid production method, refer to Appendix A. This standard protocol centers around larger batch sizes and therefore a 3 inch diameter flat disc stirrer is used in conjunction with a 3 L reaction vessel. A further iteration of the process, to improve repeatability, involved a slight change to step 4.3.5 in the “batch” type process protocol.  The time of blending was increased from 1 hour to 3 hours.  It is hypothesized that the added blend time leads to greater breakdown of the mucin proteins which caused increased homogeneity of the fluid.

Improved repeatability of the fluid in absorbent material evaluation was primarily investigated by use of an intake/rewet test. From Graph 1 in Appendix B, the variability found in the 1 hour blend time simulant is approximately six times higher compared to the 3 hr blend time simulant. The fluid intake rate for the 1 hour blend also increases as a function of time as shown in Graph 2 in Appendix B, while the fluid intake rate for the 3 hour blend remains constant. From a fluid property standpoint, changing from a “bag” process to a “batc...