David Saylor commited on
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8dc7178
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1 Parent(s): 267010d

fixed supplementary md files

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- <h1 style="text-align:center"><font color="#0070C0">C</font>olor <font color="#0070C0">H</font>azard and <font color="#0070C0">RIS</font>k calculator (CHRIS) </h1>
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  </header>
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  <h2 id="context-of-use-cou">Context of Use (COU)</h2>
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  <p>The Color Hazard and RISk calculator (CHRIS) is (proposed to be) qualified to conduct screening level risk assessments to aid in the biocompatibility evaluation of polymeric medical device components that contain color additives (CAs)<a href="#fn1" class="footnote-ref" id="fnref1" role="doc-noteref"><sup>1</sup></a>. These assessments can assist device manufacturers by providing instantaneous feedback on whether the presence of CAs or other additives and impurities associated with CAs in a device would require additional justification and/or testing to demonstrate acceptable biological risk. The output of CHRIS is a conservative margin of safety (MOS = toxicological safety limit ÷ exposure dose) value for a CA (and associated additives and impurities) contained within a polymeric medical device component. Based on the MOS value, the calculator determines if further assessment of one or more biocompatibility endpoints is necessary for the CA and/or associated impurities.</p>
 
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  </header>
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  <h2 id="context-of-use-cou">Context of Use (COU)</h2>
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  <p>The Color Hazard and RISk calculator (CHRIS) is (proposed to be) qualified to conduct screening level risk assessments to aid in the biocompatibility evaluation of polymeric medical device components that contain color additives (CAs)<a href="#fn1" class="footnote-ref" id="fnref1" role="doc-noteref"><sup>1</sup></a>. These assessments can assist device manufacturers by providing instantaneous feedback on whether the presence of CAs or other additives and impurities associated with CAs in a device would require additional justification and/or testing to demonstrate acceptable biological risk. The output of CHRIS is a conservative margin of safety (MOS = toxicological safety limit ÷ exposure dose) value for a CA (and associated additives and impurities) contained within a polymeric medical device component. Based on the MOS value, the calculator determines if further assessment of one or more biocompatibility endpoints is necessary for the CA and/or associated impurities.</p>
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  </header>
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  <h2 id="frequently-asked-questions">Frequently asked questions</h2>
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  <h3 id="what-is-the-primary-purpose-of-chris">What is the primary purpose of CHRIS?</h3>
 
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  <h2 id="frequently-asked-questions">Frequently asked questions</h2>
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  <h3 id="what-is-the-primary-purpose-of-chris">What is the primary purpose of CHRIS?</h3>
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  </header>
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- <h2 id="color-hazard-and-risk-calculator-chris">Color Hazard and RISk calculator (CHRIS)</h2>
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- <h3 id="overview">Overview</h3>
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  <p>The Color Hazard and RISk calculator (CHRIS) is a tool under development within the Center for Devices and Radiological Health (CDRH) at the Food and Drug Administration (FDA). The tool enables the user to perform rapid, screening level toxicological risk assessments of color additives and additives and impurities associated with the color additive that might be released from a polymer medical device component. CHRIS applies a model that computes an exposure estimate and compares the result to a tolerable exposure (TE) or threshold of toxicological concern (TTC) value. The tool assists the user in determining (a) whether the toxicological risk of a color additive associated substance should be further assessed and/or (b) the potential impact of the substance on device biocompatibility.</p>
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  <p><strong>Disclaimer: CHRIS only addresses risk associated with the presence of color additives and additives and impurities associated with the color additive. Therefore, a favorable outcome by CHRIS does not imply acceptable biological risk for the final finished form of a medical device. Further, a successful CHRIS evaluation does not address local biocompatibility endpoints, and therefore additional testing may be needed despite a positive outcome from CHRIS. Because there may be additional restrictions based on specific device guidance and code of federal regulation (CFR) listings, users should also review the relevant documents for their device type and color additive.</strong></p>
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- <h3 id="important-considerations">Important considerations</h3>
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  <ol type="1">
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  <li><p>CHRIS assists in screening the potential risk of a color additive associated substance in a polymer medical device component. Because color additives and concentrates may contain multiple distinct substances, e.g. impurities and carrier resins, CHRIS can be used to evaluate each substance present in the component individually.</p></li>
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  <li><p>If a color additive associated substance is present in multiple polymer medical device components, CHRIS will not screen the potential risk of the substance from all the polymer components that contain it. CHRIS exposure estimates from each component may be manually summated to estimate total exposure to each substance and manually compared to the TE or TTC for that substance.</p></li>
@@ -17,7 +16,7 @@
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  <li><p>CHRIS cannot be used to screen the potential risk of polymer medical device components that contact the body by the inhalation route.</p></li>
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  <li><p>The exposure model employed by CHRIS assumes a plane sheet geometry as worst-case. This assumption should be valid for most medical device components; however, potential exceptions exist. Specifically, this assumption can underestimate exposure when the geometry of the exposed surface area is concave, e.g. body contact is limited to the lumen of a catheter. When the exposed surface area is concave, underestimating exposure can be mitigated by assuming the patient will be exposed to all surfaces of the component, i.e. exposed surface area = total component surface area.</p></li>
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  </ol>
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- <h3 id="assumptions">Assumptions</h3>
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  <p>In addition to plane sheet geometry, four additional assumptions were made in the derivation of the exposure model, which include:</p>
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  <ol type="1">
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  <li>The polymer does not swell or degrade in-vivo.</li>
@@ -26,27 +25,27 @@
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  <li>The total amount of color additive is present in dilute concentrations (&lt;= 2 %) within the colored component</li>
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  </ol>
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  <p>It is important that your colored polymer component complies with the above assumptions so that a conservative exposure estimate is computed.</p>
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- <h3 id="usage">Usage</h3>
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  <p>The user inputs the following information into CHRIS: (a) the identity, molecular weight (for unlisted compounds), and amount, (b) the identity, mass, and (approximate) density of the polymer matrix, and (c) three (2) medical device characteristics. The required information is described in detail below:</p>
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- <h4 id="color-additive">Color additive</h4>
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  <p><em>Identity</em> - Select the color additive in the component being evaluated via the pull down list. If the color additive is not explicitly listed, please choose either “Other metal oxide color additive” or “Other non-metal oxide color additive” and enter the chemical name, including CAS # if known. If “Other non-metal oxide color additive” is selected, please enter the molecular weight of the color additive in grams per mole. If you are evaluating an additive associated with a color additive please select “Other compound (non-color additive)” and enter the chemical name and molecular weight. Note that the CHRIS is limited to color additive associated substances with molecular weight between 100 and 1100 g/mol. For compounds with molecular weight &gt; 1100 g/mol, this value can be used for a conservative exposure estimate.</p>
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  <p><em>Molecular weight</em> - Enter the molecular weight of the substance in grams per mole.</p>
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  <p><em>Amount</em> - Enter the total mass of the substance in the component being evaluated expressed in milligrams.</p>
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  <p><em>Total impurity concentration</em> - If you have selected a color additive, please enter the combined concentration of all impurities associated with the color additive as a percentage (% mass/mass).</p>
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- <h4 id="polymer-matrix">Polymer matrix</h4>
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  <p><em>Matrix</em> - Please select your polymer matrix from the list. If your polymer is not listed below, please select “Other polymer”. For polymer mixtures/blends, co-polymers, or composites (e.g. glass fiber reinforced matrices), the component or phase that is worst-case for exposure, i.e. the softest or least glassy (lowest Tg) component can be selected if listed (which, in turn, assumes the entire system is composed of the worst-case component or phase). In these scenarios, a justification should be provided for the choice of worst-case component of the polymer system.</p>
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  <p><em>Mass</em> - Enter the mass of the polymer matrix in grams.</p>
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  <p><em>Density</em> - Enter the estimated density of the polymer matrix in grams per cubic centimeter. Note that a rough estimate (e.g. +/- 10%) is acceptable.</p>
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- <h4 id="device-characteristics">Device characteristics</h4>
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  <p><em>Exposed surface area</em> - Enter the patient contacting surface area of the color additive containing component being evaluated in square centimeters. This includes both direct and indirect patient contact.</p>
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  <p><em>Exposure type</em> - Select the appropriate exposure category: &gt; 30 days = long-term, &gt; 24 hours - 30 days = prolonged, ≤ 24 hours = limited. For limited exposures (≤ 24 hours), please enter the maximum exposure time in hours.</p>
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- <h4 id="conformance-to-assumptions">Conformance to Assumptions</h4>
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  <p>The exposure model relies on assumptions that are typically valid for bulk solutes in polymeric device components. However, if any of the assumptions are violated the exposure calculation may not remain protective. Therefore, if the output of CHRIS is used to support a submission to CDRH, users must confirm conformance to the underlying assumptions or provide supporting justification. Examples of considerations when confirming conformance are provided below:</p>
45
  <p><em>Biostability of the matrix</em> - While many of the matrices listed within CHRIS will not appreciably swell or degrade in any physiological environment, this can not be generalized. For example, silicones may swell in lipid-rich environments. Chemical compatibility of the polymer matrix with the use environment can be assessed based on historical use and/or evaluation of swelling and/or degradation propensity in physiologically relevant media.</p>
46
  <p><em>Particle/aggregate size and distribution</em> - CHRIS relies on the color additive having a distribution that is macroscopically homogeneous within the matrix (e.g. CAs used for surface marking would be excluded); thus, any particles or aggregates must be small relative to the component and homogeneously distributed. This can be confirmed/justified through the use of particle coatings and/or dispersants in the concentrate to prevent aggregation and promote homogeneity, macroscopic observations of color uniformity, and/or microscopic observations to evaluate the potential for surface segregation phenomena, such as blooming.</p>
47
  <p><em>Dilute concentration</em> - The model relies on a concentration independent diffusion coefficient, which assumes any color additives are present only in dilute quantities. Confirming that the total amount of color additives present is ≤ 2 m/v % is sufficient to conform with this assumption. It may be possible to justify that the CHRIS calculation for a dilute compound will remain protective if the total concentration is in excess of 2 m/v %, if the presence of additional compound could reasonably be expected to inhibit rather than promote diffusion, e.g. second phase particulates.</p>
48
  <p><em>Matrix stability</em> - The model parameters/transport properties are established using worst-case values reported in the literature. However, it is unclear if the reported values account for potential degradation (e.g. during sterilization) or other physicochemical changes (e.g. excessive plasticization) that may occur during manufacturing and negatively impact these values. Polymer stability can be confirmed/justified by evidence supporting that manufacturing (including sterilization) does not alter the matrix material of the final device.</p>
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- <h4 id="exposure-assessment">Exposure Assessment</h4>
50
  <p>Once the fields described have been populated for the polymeric component being evaluated, click the <strong>Estimate exposure</strong> button. The risk assessment output includes the following information:</p>
51
  <ol type="1">
52
  <li><p>Exposure estimation - including the model equations and parameters used in the calculation</p></li>
@@ -54,5 +53,5 @@
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  <li><p>Screening level toxicological risk assessment - A summary of the screening level TRA including calculated margin of safety including any important additional considerations regarding the analysis.</p></li>
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  <li><p>Color additive impurities risk assessment (if applicable) - A summary of a screening level TRA comparing the total amount of impurities to the appropriate TTC value.</p></li>
56
  </ol>
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- <h3 id="further-information">Further information</h3>
58
  <p>The answers to many frequently asked questions can be found <a href="FAQ.html">here</a>. If your question is not already addressed or if you have specific issues with CHRIS, please contact Dave Saylor: <a href="mailto:david.saylor@fda.hhs.gov" class="email">david.saylor@fda.hhs.gov</a>.</p>
 
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  </header>
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+ <h2 id="overview">Overview</h2>
 
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  <p>The Color Hazard and RISk calculator (CHRIS) is a tool under development within the Center for Devices and Radiological Health (CDRH) at the Food and Drug Administration (FDA). The tool enables the user to perform rapid, screening level toxicological risk assessments of color additives and additives and impurities associated with the color additive that might be released from a polymer medical device component. CHRIS applies a model that computes an exposure estimate and compares the result to a tolerable exposure (TE) or threshold of toxicological concern (TTC) value. The tool assists the user in determining (a) whether the toxicological risk of a color additive associated substance should be further assessed and/or (b) the potential impact of the substance on device biocompatibility.</p>
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  <p><strong>Disclaimer: CHRIS only addresses risk associated with the presence of color additives and additives and impurities associated with the color additive. Therefore, a favorable outcome by CHRIS does not imply acceptable biological risk for the final finished form of a medical device. Further, a successful CHRIS evaluation does not address local biocompatibility endpoints, and therefore additional testing may be needed despite a positive outcome from CHRIS. Because there may be additional restrictions based on specific device guidance and code of federal regulation (CFR) listings, users should also review the relevant documents for their device type and color additive.</strong></p>
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+ <h2 id="important-considerations">Important considerations</h2>
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  <ol type="1">
13
  <li><p>CHRIS assists in screening the potential risk of a color additive associated substance in a polymer medical device component. Because color additives and concentrates may contain multiple distinct substances, e.g. impurities and carrier resins, CHRIS can be used to evaluate each substance present in the component individually.</p></li>
14
  <li><p>If a color additive associated substance is present in multiple polymer medical device components, CHRIS will not screen the potential risk of the substance from all the polymer components that contain it. CHRIS exposure estimates from each component may be manually summated to estimate total exposure to each substance and manually compared to the TE or TTC for that substance.</p></li>
 
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  <li><p>CHRIS cannot be used to screen the potential risk of polymer medical device components that contact the body by the inhalation route.</p></li>
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  <li><p>The exposure model employed by CHRIS assumes a plane sheet geometry as worst-case. This assumption should be valid for most medical device components; however, potential exceptions exist. Specifically, this assumption can underestimate exposure when the geometry of the exposed surface area is concave, e.g. body contact is limited to the lumen of a catheter. When the exposed surface area is concave, underestimating exposure can be mitigated by assuming the patient will be exposed to all surfaces of the component, i.e. exposed surface area = total component surface area.</p></li>
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  </ol>
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+ <h2 id="assumptions">Assumptions</h2>
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  <p>In addition to plane sheet geometry, four additional assumptions were made in the derivation of the exposure model, which include:</p>
21
  <ol type="1">
22
  <li>The polymer does not swell or degrade in-vivo.</li>
 
25
  <li>The total amount of color additive is present in dilute concentrations (&lt;= 2 %) within the colored component</li>
26
  </ol>
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  <p>It is important that your colored polymer component complies with the above assumptions so that a conservative exposure estimate is computed.</p>
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+ <h2 id="usage">Usage</h2>
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  <p>The user inputs the following information into CHRIS: (a) the identity, molecular weight (for unlisted compounds), and amount, (b) the identity, mass, and (approximate) density of the polymer matrix, and (c) three (2) medical device characteristics. The required information is described in detail below:</p>
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+ <h3 id="color-additive">Color additive</h3>
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  <p><em>Identity</em> - Select the color additive in the component being evaluated via the pull down list. If the color additive is not explicitly listed, please choose either “Other metal oxide color additive” or “Other non-metal oxide color additive” and enter the chemical name, including CAS # if known. If “Other non-metal oxide color additive” is selected, please enter the molecular weight of the color additive in grams per mole. If you are evaluating an additive associated with a color additive please select “Other compound (non-color additive)” and enter the chemical name and molecular weight. Note that the CHRIS is limited to color additive associated substances with molecular weight between 100 and 1100 g/mol. For compounds with molecular weight &gt; 1100 g/mol, this value can be used for a conservative exposure estimate.</p>
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  <p><em>Molecular weight</em> - Enter the molecular weight of the substance in grams per mole.</p>
33
  <p><em>Amount</em> - Enter the total mass of the substance in the component being evaluated expressed in milligrams.</p>
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  <p><em>Total impurity concentration</em> - If you have selected a color additive, please enter the combined concentration of all impurities associated with the color additive as a percentage (% mass/mass).</p>
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+ <h3 id="polymer-matrix">Polymer matrix</h3>
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  <p><em>Matrix</em> - Please select your polymer matrix from the list. If your polymer is not listed below, please select “Other polymer”. For polymer mixtures/blends, co-polymers, or composites (e.g. glass fiber reinforced matrices), the component or phase that is worst-case for exposure, i.e. the softest or least glassy (lowest Tg) component can be selected if listed (which, in turn, assumes the entire system is composed of the worst-case component or phase). In these scenarios, a justification should be provided for the choice of worst-case component of the polymer system.</p>
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  <p><em>Mass</em> - Enter the mass of the polymer matrix in grams.</p>
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  <p><em>Density</em> - Enter the estimated density of the polymer matrix in grams per cubic centimeter. Note that a rough estimate (e.g. +/- 10%) is acceptable.</p>
39
+ <h3 id="device-characteristics">Device characteristics</h3>
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  <p><em>Exposed surface area</em> - Enter the patient contacting surface area of the color additive containing component being evaluated in square centimeters. This includes both direct and indirect patient contact.</p>
41
  <p><em>Exposure type</em> - Select the appropriate exposure category: &gt; 30 days = long-term, &gt; 24 hours - 30 days = prolonged, ≤ 24 hours = limited. For limited exposures (≤ 24 hours), please enter the maximum exposure time in hours.</p>
42
+ <h3 id="conformance-to-assumptions">Conformance to Assumptions</h3>
43
  <p>The exposure model relies on assumptions that are typically valid for bulk solutes in polymeric device components. However, if any of the assumptions are violated the exposure calculation may not remain protective. Therefore, if the output of CHRIS is used to support a submission to CDRH, users must confirm conformance to the underlying assumptions or provide supporting justification. Examples of considerations when confirming conformance are provided below:</p>
44
  <p><em>Biostability of the matrix</em> - While many of the matrices listed within CHRIS will not appreciably swell or degrade in any physiological environment, this can not be generalized. For example, silicones may swell in lipid-rich environments. Chemical compatibility of the polymer matrix with the use environment can be assessed based on historical use and/or evaluation of swelling and/or degradation propensity in physiologically relevant media.</p>
45
  <p><em>Particle/aggregate size and distribution</em> - CHRIS relies on the color additive having a distribution that is macroscopically homogeneous within the matrix (e.g. CAs used for surface marking would be excluded); thus, any particles or aggregates must be small relative to the component and homogeneously distributed. This can be confirmed/justified through the use of particle coatings and/or dispersants in the concentrate to prevent aggregation and promote homogeneity, macroscopic observations of color uniformity, and/or microscopic observations to evaluate the potential for surface segregation phenomena, such as blooming.</p>
46
  <p><em>Dilute concentration</em> - The model relies on a concentration independent diffusion coefficient, which assumes any color additives are present only in dilute quantities. Confirming that the total amount of color additives present is ≤ 2 m/v % is sufficient to conform with this assumption. It may be possible to justify that the CHRIS calculation for a dilute compound will remain protective if the total concentration is in excess of 2 m/v %, if the presence of additional compound could reasonably be expected to inhibit rather than promote diffusion, e.g. second phase particulates.</p>
47
  <p><em>Matrix stability</em> - The model parameters/transport properties are established using worst-case values reported in the literature. However, it is unclear if the reported values account for potential degradation (e.g. during sterilization) or other physicochemical changes (e.g. excessive plasticization) that may occur during manufacturing and negatively impact these values. Polymer stability can be confirmed/justified by evidence supporting that manufacturing (including sterilization) does not alter the matrix material of the final device.</p>
48
+ <h3 id="exposure-assessment">Exposure Assessment</h3>
49
  <p>Once the fields described have been populated for the polymeric component being evaluated, click the <strong>Estimate exposure</strong> button. The risk assessment output includes the following information:</p>
50
  <ol type="1">
51
  <li><p>Exposure estimation - including the model equations and parameters used in the calculation</p></li>
 
53
  <li><p>Screening level toxicological risk assessment - A summary of the screening level TRA including calculated margin of safety including any important additional considerations regarding the analysis.</p></li>
54
  <li><p>Color additive impurities risk assessment (if applicable) - A summary of a screening level TRA comparing the total amount of impurities to the appropriate TTC value.</p></li>
55
  </ol>
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+ <h2 id="further-information">Further information</h2>
57
  <p>The answers to many frequently asked questions can be found <a href="FAQ.html">here</a>. If your question is not already addressed or if you have specific issues with CHRIS, please contact Dave Saylor: <a href="mailto:david.saylor@fda.hhs.gov" class="email">david.saylor@fda.hhs.gov</a>.</p>
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  </header>
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  ```
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- ## Color Hazard and RISk calculator (CHRIS)
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-
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- ### Overview
14
 
15
  The Color Hazard and RISk calculator (CHRIS) is a tool under development within the Center for Devices and Radiological Health (CDRH) at the Food and Drug Administration (FDA). The tool enables the user to perform rapid, screening level toxicological risk assessments of color additives and additives and impurities associated with the color additive that might be released from a polymer medical device component. CHRIS applies a model that computes an exposure estimate and compares the result to a tolerable exposure (TE) or threshold of toxicological concern (TTC) value. The tool assists the user in determining (a) whether the toxicological risk of a color additive associated substance should be further assessed and/or (b) the potential impact of the substance on device biocompatibility.
16
 
17
  **Disclaimer: CHRIS only addresses risk associated with the presence of color additives and additives and impurities associated with the color additive. Therefore, a favorable outcome by CHRIS does not imply acceptable biological risk for the final finished form of a medical device. Further, a successful CHRIS evaluation does not address local biocompatibility endpoints, and therefore additional testing may be needed despite a positive outcome from CHRIS. Because there may be additional restrictions based on specific device guidance and code of federal regulation (CFR) listings, users should also review the relevant documents for their device type and color additive.**
18
 
19
- ### Important considerations
20
 
21
  (1) CHRIS assists in screening the potential risk of a color additive associated substance in a polymer medical device component. Because color additives and concentrates may contain multiple distinct substances, e.g. impurities and carrier resins, CHRIS can be used to evaluate each substance present in the component individually.
22
 
@@ -28,7 +26,7 @@ The Color Hazard and RISk calculator (CHRIS) is a tool under development within
28
 
29
  (5) The exposure model employed by CHRIS assumes a plane sheet geometry as worst-case. This assumption should be valid for most medical device components; however, potential exceptions exist. Specifically, this assumption can underestimate exposure when the geometry of the exposed surface area is concave, e.g. body contact is limited to the lumen of a catheter. When the exposed surface area is concave, underestimating exposure can be mitigated by assuming the patient will be exposed to all surfaces of the component, i.e. exposed surface area = total component surface area.
30
 
31
- ### Assumptions
32
 
33
  In addition to plane sheet geometry, four additional assumptions were made in the derivation of the exposure model, which include:
34
 
@@ -39,11 +37,11 @@ In addition to plane sheet geometry, four additional assumptions were made in th
39
 
40
  It is important that your colored polymer component complies with the above assumptions so that a conservative exposure estimate is computed.
41
 
42
- ### Usage
43
 
44
  The user inputs the following information into CHRIS: (a) the identity, molecular weight (for unlisted compounds), and amount, (b) the identity, mass, and (approximate) density of the polymer matrix, and (c) three (2) medical device characteristics. The required information is described in detail below:
45
 
46
- #### Color additive
47
 
48
  *Identity* - Select the color additive in the component being evaluated via the pull down list. If the color additive is not explicitly listed, please choose either "Other metal oxide color additive" or "Other non-metal oxide color additive" and enter the chemical name, including CAS # if known. If "Other non-metal oxide color additive" is selected, please enter the molecular weight of the color additive in grams per mole. If you are evaluating an additive associated with a color additive please select "Other compound (non-color additive)" and enter the chemical name and molecular weight. Note that the CHRIS is limited to color additive associated substances with molecular weight between 100 and 1100 g/mol. For compounds with molecular weight > 1100 g/mol, this value can be used for a conservative exposure estimate.
49
 
@@ -53,7 +51,7 @@ The user inputs the following information into CHRIS: (a) the identity, molecula
53
 
54
  *Total impurity concentration* - If you have selected a color additive, please enter the combined concentration of all impurities associated with the color additive as a percentage (% mass/mass).
55
 
56
- #### Polymer matrix
57
 
58
  *Matrix* - Please select your polymer matrix from the list. If your polymer is not listed below, please select "Other polymer". For polymer mixtures/blends, co-polymers, or composites (e.g. glass fiber reinforced matrices), the component or phase that is worst-case for exposure, i.e. the softest or least glassy (lowest Tg) component can be selected if listed (which, in turn, assumes the entire system is composed of the worst-case component or phase). In these scenarios, a justification should be provided for the choice of worst-case component of the polymer system.
59
 
@@ -61,13 +59,13 @@ The user inputs the following information into CHRIS: (a) the identity, molecula
61
 
62
  *Density* - Enter the estimated density of the polymer matrix in grams per cubic centimeter. Note that a rough estimate (e.g. +/- 10%) is acceptable.
63
 
64
- #### Device characteristics
65
 
66
  *Exposed surface area* - Enter the patient contacting surface area of the color additive containing component being evaluated in square centimeters. This includes both direct and indirect patient contact.
67
 
68
  *Exposure type* - Select the appropriate exposure category: > 30 days = long-term, > 24 hours - 30 days = prolonged, ≤ 24 hours = limited. For limited exposures (≤ 24 hours), please enter the maximum exposure time in hours.
69
 
70
- #### Conformance to Assumptions
71
 
72
  The exposure model relies on assumptions that are typically valid for bulk solutes in polymeric device components. However, if any of the assumptions are violated the exposure calculation may not remain protective. Therefore, if the output of CHRIS is used to support a submission to CDRH, users must confirm conformance to the underlying assumptions or provide supporting justification. Examples of considerations when confirming conformance are provided below:
73
 
@@ -79,7 +77,7 @@ The exposure model relies on assumptions that are typically valid for bulk solut
79
 
80
  *Matrix stability* - The model parameters/transport properties are established using worst-case values reported in the literature. However, it is unclear if the reported values account for potential degradation (e.g. during sterilization) or other physicochemical changes (e.g. excessive plasticization) that may occur during manufacturing and negatively impact these values. Polymer stability can be confirmed/justified by evidence supporting that manufacturing (including sterilization) does not alter the matrix material of the final device.
81
 
82
- #### Exposure Assessment
83
 
84
  Once the fields described have been populated for the polymeric component being evaluated, click the **Estimate exposure** button. The risk assessment output includes the following information:
85
 
@@ -91,7 +89,7 @@ Once the fields described have been populated for the polymeric component being
91
 
92
  (4) Color additive impurities risk assessment (if applicable) - A summary of a screening level TRA comparing the total amount of impurities to the appropriate TTC value.
93
 
94
- ### Further information
95
 
96
  The answers to many frequently asked questions can be found [here](FAQ.html). If your question is not already addressed or if you have specific issues with CHRIS, please contact Dave Saylor: <david.saylor@fda.hhs.gov>.
97
 
 
4
  <img src="images/FDAlogo.png" style="float: left;" height="100"/>
5
  <img src="images/FDAgraphic.png" style="float: right;" height="100"/>
6
  <br clear="all" />
7
+ <h1 style="text-align:center"><font color="#0070C0">CH</font>emical <font color="#0070C0">RIS</font>k calculator (CHRIS)- color additives</h1>
8
  </header>
9
  ```
10
 
11
+ ## Overview
 
 
12
 
13
  The Color Hazard and RISk calculator (CHRIS) is a tool under development within the Center for Devices and Radiological Health (CDRH) at the Food and Drug Administration (FDA). The tool enables the user to perform rapid, screening level toxicological risk assessments of color additives and additives and impurities associated with the color additive that might be released from a polymer medical device component. CHRIS applies a model that computes an exposure estimate and compares the result to a tolerable exposure (TE) or threshold of toxicological concern (TTC) value. The tool assists the user in determining (a) whether the toxicological risk of a color additive associated substance should be further assessed and/or (b) the potential impact of the substance on device biocompatibility.
14
 
15
  **Disclaimer: CHRIS only addresses risk associated with the presence of color additives and additives and impurities associated with the color additive. Therefore, a favorable outcome by CHRIS does not imply acceptable biological risk for the final finished form of a medical device. Further, a successful CHRIS evaluation does not address local biocompatibility endpoints, and therefore additional testing may be needed despite a positive outcome from CHRIS. Because there may be additional restrictions based on specific device guidance and code of federal regulation (CFR) listings, users should also review the relevant documents for their device type and color additive.**
16
 
17
+ ## Important considerations
18
 
19
  (1) CHRIS assists in screening the potential risk of a color additive associated substance in a polymer medical device component. Because color additives and concentrates may contain multiple distinct substances, e.g. impurities and carrier resins, CHRIS can be used to evaluate each substance present in the component individually.
20
 
 
26
 
27
  (5) The exposure model employed by CHRIS assumes a plane sheet geometry as worst-case. This assumption should be valid for most medical device components; however, potential exceptions exist. Specifically, this assumption can underestimate exposure when the geometry of the exposed surface area is concave, e.g. body contact is limited to the lumen of a catheter. When the exposed surface area is concave, underestimating exposure can be mitigated by assuming the patient will be exposed to all surfaces of the component, i.e. exposed surface area = total component surface area.
28
 
29
+ ## Assumptions
30
 
31
  In addition to plane sheet geometry, four additional assumptions were made in the derivation of the exposure model, which include:
32
 
 
37
 
38
  It is important that your colored polymer component complies with the above assumptions so that a conservative exposure estimate is computed.
39
 
40
+ ## Usage
41
 
42
  The user inputs the following information into CHRIS: (a) the identity, molecular weight (for unlisted compounds), and amount, (b) the identity, mass, and (approximate) density of the polymer matrix, and (c) three (2) medical device characteristics. The required information is described in detail below:
43
 
44
+ ### Color additive
45
 
46
  *Identity* - Select the color additive in the component being evaluated via the pull down list. If the color additive is not explicitly listed, please choose either "Other metal oxide color additive" or "Other non-metal oxide color additive" and enter the chemical name, including CAS # if known. If "Other non-metal oxide color additive" is selected, please enter the molecular weight of the color additive in grams per mole. If you are evaluating an additive associated with a color additive please select "Other compound (non-color additive)" and enter the chemical name and molecular weight. Note that the CHRIS is limited to color additive associated substances with molecular weight between 100 and 1100 g/mol. For compounds with molecular weight > 1100 g/mol, this value can be used for a conservative exposure estimate.
47
 
 
51
 
52
  *Total impurity concentration* - If you have selected a color additive, please enter the combined concentration of all impurities associated with the color additive as a percentage (% mass/mass).
53
 
54
+ ### Polymer matrix
55
 
56
  *Matrix* - Please select your polymer matrix from the list. If your polymer is not listed below, please select "Other polymer". For polymer mixtures/blends, co-polymers, or composites (e.g. glass fiber reinforced matrices), the component or phase that is worst-case for exposure, i.e. the softest or least glassy (lowest Tg) component can be selected if listed (which, in turn, assumes the entire system is composed of the worst-case component or phase). In these scenarios, a justification should be provided for the choice of worst-case component of the polymer system.
57
 
 
59
 
60
  *Density* - Enter the estimated density of the polymer matrix in grams per cubic centimeter. Note that a rough estimate (e.g. +/- 10%) is acceptable.
61
 
62
+ ### Device characteristics
63
 
64
  *Exposed surface area* - Enter the patient contacting surface area of the color additive containing component being evaluated in square centimeters. This includes both direct and indirect patient contact.
65
 
66
  *Exposure type* - Select the appropriate exposure category: > 30 days = long-term, > 24 hours - 30 days = prolonged, ≤ 24 hours = limited. For limited exposures (≤ 24 hours), please enter the maximum exposure time in hours.
67
 
68
+ ### Conformance to Assumptions
69
 
70
  The exposure model relies on assumptions that are typically valid for bulk solutes in polymeric device components. However, if any of the assumptions are violated the exposure calculation may not remain protective. Therefore, if the output of CHRIS is used to support a submission to CDRH, users must confirm conformance to the underlying assumptions or provide supporting justification. Examples of considerations when confirming conformance are provided below:
71
 
 
77
 
78
  *Matrix stability* - The model parameters/transport properties are established using worst-case values reported in the literature. However, it is unclear if the reported values account for potential degradation (e.g. during sterilization) or other physicochemical changes (e.g. excessive plasticization) that may occur during manufacturing and negatively impact these values. Polymer stability can be confirmed/justified by evidence supporting that manufacturing (including sterilization) does not alter the matrix material of the final device.
79
 
80
+ ### Exposure Assessment
81
 
82
  Once the fields described have been populated for the polymeric component being evaluated, click the **Estimate exposure** button. The risk assessment output includes the following information:
83
 
 
89
 
90
  (4) Color additive impurities risk assessment (if applicable) - A summary of a screening level TRA comparing the total amount of impurities to the appropriate TTC value.
91
 
92
+ ## Further information
93
 
94
  The answers to many frequently asked questions can be found [here](FAQ.html). If your question is not already addressed or if you have specific issues with CHRIS, please contact Dave Saylor: <david.saylor@fda.hhs.gov>.
95
 
static/exposure_COU.html CHANGED
@@ -3,7 +3,7 @@
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  <img src="images/FDAlogo.png" style="float: left;" height="100"/>
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  <img src="images/FDAgraphic.png" style="float: right;" height="100"/>
5
  <br clear="all" />
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- <h1 style="text-align:center"><font color="#0070C0">C</font>olor <font color="#0070C0">H</font>azard and <font color="#0070C0">RIS</font>k calculator (CHRIS) </h1>
7
  </header>
8
  <h2 id="context-of-use-cou">Context of Use (COU)</h2>
9
  <p>The bulk chemical module of the CHemical RISk calculator (CHRIS) is (proposed to be) qualified to conduct screening level risk assessments to aid in the biocompatibility evaluation of bulk additives and impurities in polymeric medical device components. These assessments can assist device manufacturers by providing instantaneous feedback on whether the presence of the bulk chemical would require additional justification and/or testing to demonstrate acceptable biological risk. The output of CHRIS is a conservative margin of safety (MOS = toxicological safety limit ÷ exposure dose) value for a bulk chemical contained within a polymeric medical device component. Based on the MOS value, the calculator determines if further assessment of one or more biocompatibility endpoints is necessary for the specific chemical.</p>
 
3
  <img src="images/FDAlogo.png" style="float: left;" height="100"/>
4
  <img src="images/FDAgraphic.png" style="float: right;" height="100"/>
5
  <br clear="all" />
6
+ <h1 style="text-align:center"><font color="#0070C0">CH</font>emical <font color="#0070C0">RIS</font>k calculator (CHRIS) - Bulk chemicals</h1>
7
  </header>
8
  <h2 id="context-of-use-cou">Context of Use (COU)</h2>
9
  <p>The bulk chemical module of the CHemical RISk calculator (CHRIS) is (proposed to be) qualified to conduct screening level risk assessments to aid in the biocompatibility evaluation of bulk additives and impurities in polymeric medical device components. These assessments can assist device manufacturers by providing instantaneous feedback on whether the presence of the bulk chemical would require additional justification and/or testing to demonstrate acceptable biological risk. The output of CHRIS is a conservative margin of safety (MOS = toxicological safety limit ÷ exposure dose) value for a bulk chemical contained within a polymeric medical device component. Based on the MOS value, the calculator determines if further assessment of one or more biocompatibility endpoints is necessary for the specific chemical.</p>
static/exposure_COU.md CHANGED
@@ -4,7 +4,7 @@
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  <img src="images/FDAlogo.png" style="float: left;" height="100"/>
5
  <img src="images/FDAgraphic.png" style="float: right;" height="100"/>
6
  <br clear="all" />
7
- <h1 style="text-align:center"><font color="#0070C0">C</font>olor <font color="#0070C0">H</font>azard and <font color="#0070C0">RIS</font>k calculator (CHRIS) </h1>
8
  </header>
9
  ```
10
 
 
4
  <img src="images/FDAlogo.png" style="float: left;" height="100"/>
5
  <img src="images/FDAgraphic.png" style="float: right;" height="100"/>
6
  <br clear="all" />
7
+ <h1 style="text-align:center"><font color="#0070C0">CH</font>emical <font color="#0070C0">RIS</font>k calculator (CHRIS) - Bulk chemicals</h1>
8
  </header>
9
  ```
10