1、Designation: F2808 10Standard Test Method forPerforming Behind-the-Knee (BTK) Test for Evaluating SkinIrritation Response to Products and Materials That ComeInto Repeated or Extended Contact with Skin1This standard is issued under the fixed designation F2808; the number immediately following the des
2、ignation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The Behind-the-Knee (BTK) met
3、hod, using thepopliteal fossa of human volunteers as a test site, simulta-neously evaluates the inherent chemical irritation, and thepotential for mechanical irritation of substrates and productsthat are designed to come into repeated or extended closecontact with the skin (see validation references
4、 1-7).2This is abilateral test comparing a test material to a reference materialwith a known safety profile.1.2 This test method shall be used by qualified health careprofessionals experienced in good clinical practice (GCP)procedures.1.3 This test method can be performed using human sub-jects on ei
5、ther intact or compromised skin. Testing should beperformed on intact skin for test substrates or products ex-pected to have contact with normal, intact skin, or for directcomparison to products with a known skin irritation profile.Testing can be performed on compromised skin for testsubstrates or p
6、roducts that may commonly come into contactwith damaged skin (for example, skin with diaper rash, orchapped skin) or skin that is expected to be hydrated.1.4 Visual scoring of erythema and dryness is performed bya trained skin grader on a pre-defined scale.1.5 Prior to use in this test, materials sh
7、all undergo overallfavorable biocompatibility testing consistent with the approachoutlined in protocol Practice F748 or ISO 10993-1:2009.Asapart of this series of testing, irritation per Practice F719 orISO 10993-10 shall be conducted.1.6 The values stated in inch-pound units are to be regardedas st
8、andard. No other units of measurement are included in thisstandard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the ap
9、plica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D6355 Test Method for Human Repeat Insult Patch Testingof Medical GlovesF719 Practice for Testing Biomaterials in Rabbits for Pri-mary Skin IrritationF748 Practice for Selecting Generic Biological Test Met
10、h-ods for Materials and Devices2.2 ISO Standards:4ISO 10993-1:2009 Biological Evaluation of MedicalDevicesPart 1: Evaluation and Testing Within a RiskManagement ProcessISO 10993-10 Biological Evaluation of Medical DevicesPart 10: Tests for Irritation and Delayed-type Hypersensi-tivity3. Terminology3
11、.1 Definitions:3.1.1 chemical irritation, nirritation caused by a physi-ological response to the chemical nature of a material. Suchphysiological responses may include: oxidation or reductionreactions, dehydration, disruption of the keratin ultra-structureor direct injury to cellular macromolecules
12、or organelles.3.1.2 compromised skin, nskin that is treated with re-peated application of surgical tape prior to the first sampleapplication.3.1.3 edema, nobservable swelling from abnormal accu-mulation of fluid in connective tissue.3.1.4 erythema, nredness of the skin.3.1.5 mechanical irritation, n
13、irritation caused by move-ment and friction of products intended to remain in contactwith the skin for extended periods of time.1This test method is under the jurisdiction of ASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.16 on Bio
14、compatibility Test Methods.Current edition approved Oct. 15, 2010. Published November 2010. DOI:10.1520/F280810.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custome
15、r Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM Internatio
16、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.6 popliteal fossa, nthe area at the back of the knee.3.1.7 reference material, na material similar in form andcomposition to the test material. The reference material shouldhave a known safety and irritation
17、 profile.3.1.8 skin grades, nvisual assessments of erythema anddryness according to a defined scale (see 10.3).3.1.9 test material, nany material or product expected tocome into contact with skin.3.1.10 trained skin grader, npersonnel who have beentrained to reliably recognize erythema and dryness r
18、eactions byusing reference examples, and by performing side-by-sidescoring with an experienced skin grader.4. Summary of Test Method4.1 Samples are applied to the back of the knee using anelastic knee band or brace. As the subjects go about theireveryday activities, normal movements generate frictio
19、n be-tween the test sample and the skin at the test site, therebyadding the element of mechanical irritation. Thus, the BTK testprotocol evaluates a combination of mechanical irritation andthe inherent chemical irritation potential of materials andproducts that come into contact with the skin.4.2 Th
20、is is a randomized, controlled, double blind study inwhich both the subjects and skin grader are unaware of thetreatment assignments. Test and reference materials are appliedfor 6 h per day, for 5 days. Skin reactions are graded forerythema and dryness prior to the first sample application (thatis,
21、at baseline), each morning prior to subsequent sampleapplications, and upon the removal of the sample at the end ofeach period.4.3 Test materials are applied, once each test day to normal,intact skin to evaluate potential reactions to products thatnormally come into contact with intact skin. To eval
22、uatepotential reactions to products that normally come into contactwith damaged skin, the skin can be compromised by using tapestripping prior to the first sample application.5. Significance and Use5.1 This test method is intended to assess a combination ofinherent chemical irritation and mechanical
23、 irritation for prod-ucts and materials expected to come into contact with the skin.It is a comparative approach whereby the potential irritation ofa test material is compared to that of a reference materialsimilar in form and composition. The reference material shouldhave a known safety and irritat
24、ion profile.6. Interferences and Precautions6.1 Possible protocol deviations that could interfere with oraffect the outcome of the study include the fit of the elasticknee band and the activity level of the subjects. As in anyclinical study, adherence to the protocol conditions will offsetany potent
25、ial confounding issues.6.2 The use of lotions, powders, creams, or skin careproducts in the skin area at the test sites during the course ofthe study may impact the study results. In addition, shaving theskin behind the knee, exposing the test sites to tanning or thesun, or swimming or hot tub use d
26、uring study participationshould not be permitted, since these practices and activitiesmay produce low levels of skin irritation in some persons.6.3 Anti-inflammatory medications may interfere with thenormal development of the skin irritation reaction and shouldnot be used during the study.6.4 Normal
27、 showering or bathing cannot be allowed duringthe sample application of 6 h per day, but can be allowedduring the 18 h each day when the test samples are not in place.6.5 Some persons will experience some degree of skinirritation at the test sites. In addition, some persons mayexperience slight disc
28、omfort from the manner in which thesamples are applied (that is, an elastic knee band). In mostcases, these effects are anticipated to be reversible whensample application concludes.7. Apparatus7.1 An artificial light source, with a 100 W incandescentdaylight blue bulb, is used to illuminate the app
29、lication areasfor erythema grading and an illuminated 103 magnifying lensis used to grade dryness.8. Reagents and Materials8.1 Elastic knee bands or braces are used to hold thesamples in place.8.2 Test materials include substrates and products that aredesigned to come into repeated or extended close
30、 contact withthe skin. The appropriate reference sample is a similar materialor product that has been demonstrated through biocompatibil-ity testing to be a non-irritant.8.3 If testing is to be conducted on compromised skin, anappropriate surgical tape is required.9. Hazards9.1 No specific hazards h
31、ave been identified for this testprotocol. However, if any of the test materials tested should fallunder biohazard then all used test materials should be handledand discarded by the test site staff following BiohazardStandard Operating Procedures (SOPs).10. Calibration and Standardization10.1 No cal
32、ibration of specific equipment is required.10.2 Skin graders shall be trained to recognize the degreesof severity of the irritation reactions described in the gradingscales given in Appendix X7.10.3 The Skin Irritation Grading Scales for Erythema andDryness (Appendix X7) are similar to those scales
33、used bycontract testing facilities in a variety of skin testing protocols,including single patch tests placed on the upper arm, multiplepatch tests in cumulative irritation testing, forearm controlledapplication testing, nasal irritation, and Human Repeat InsultPatch Testing (as outlined in Test Met
34、hod D6355). Skin gradersshould be trained to recognize erythema and dryness reactionsby performing side-by-side scoring of patch tests or BTK testswith an experienced skin grader until the trainee can reliablyrecognize the reactions.11. Institutional Review and Informed Consent11.1 Institutional Rev
35、iew:11.1.1 The method for this study and qualification of per-sons conducting the study shall be reviewed by an appropriateInstitutional Review Board (IRB).F2808 10211.2 Informed Consent:11.2.1 An informed consent document should be read,understood, and signed by the subjects prior to initiating the
36、study.12. Procedure12.1 SubjectsEach experiment should include a generalsample size calculation done by a statistician to determine thenumber of subjects in the study (see 13.3). A sufficient numberof subjects should be recruited give the study sufficient powerto achieve a statistically significant
37、difference between thereference and test samples, and to allow for a drop out rateconsistent with the norms for the test facility. In the course ofrecruitment, demographic information (age, sex, ethnicity,height, and weight) should be collected on each subject.Subjects should be healthy adults betwe
38、en 18 and 65 years ofage, who meet the inclusion/exclusion criteria and preferablywith Fitzpatrick skin type I to IV mixture.12.1.1 Specific inclusion/exclusion criteria are as follows(see Appendix X1):12.1.1.1 Inclusion CriteriaSubjects who:(1) Have read, understood, and signed the informed con-sen
39、t;(2) Are at least 18 years old;(3) Are no more than 65 years old;(4) Are in general good health (self-declared);(5) Are Fitzpatrick skin type I to IV (see Appendix X2);(6) Agree to refrain from using lotions, creams, powders,or other skin preparations on the skin in the area behind theknee during p
40、articipation in the study;(7) Agree to refrain from shaving the skin in the areabehind the knee during participation in the study;(8) Agree to refrain from swimming or hot tub use duringparticipation in the study;(9) Agree to refrain from fitness training during sampleapplication;(10) Agree to refra
41、in from tanning or sun exposure to thetest area during participation in the study;(11) Agree to refrain from taking anti-inflammatory medi-cation such as acetylsalicylic acid (aspirin), acetaminophen,ibuprofen, and naproxen;(12) Agree to comply with all study protocol requirements.12.1.1.2 Exclusion
42、 Criteria:(1) Fitzpatrick skin type V to VI (see Appendix X2) due todifficulties in scoring visible erythema on highly pigmentedskin;(2) Cuts, scratches, rashes, sunburn, acne, abrasions, scartissue, tattoos, or any other skin abnormality at the test sites;(3) Psoriasis, eczema, skin cancer, or any
43、active dermatitisthat could potentially interfere with interpretation of test resultsat the test sites;(4) Use of corticosteroids (oral or topical) or other types ofdrugs that may interfere with the normal development ofirritation, inflammation, or immune reactions;(5) Participation in a behind-the-
44、knee study within the lastfour weeks;(6) Known irritancy or discomfort in the area behind theknee which would prevent the subject from wearing a kneebrace for 6 h each day during study participation;(7) Current pregnancy or lactation (self-reported);(8) Diabetes or kidney disease (self-reported) whi
45、ch maybe associated with potential circulatory problems;(9) Heart or circulatory disease (including blood clots)(self-reported) which may be exacerbated by wearing an elasticknee band for 6 h each day during study participation;(10) Leg varicosities which would interfere with thesubjects wearing a k
46、nee brace for 6 h each day during studyparticipation;(11) Arthritis in the lower extremities;(12) Known allergies to tape(s) and/or adhesives;(13) History of edema in the lower extremities;(14) Knee circumference greater than 21 in. (since 21 in. isthe maximum size that can be accommodated by manyco
47、mmercial elastic knee bands).12.1.2 Once eligibility is confirmed, the areas behind theknees are screened for cuts, scratches, rashes, sunburn, acne,abrasions, scar tissue, tattoos, or any other condition that couldprevent a clear assessment of their skin during the test portionof the study.12.1.3 A
48、t the enrollment visit, subjects are fitted for theelastic knee band based on the manufacturers recommenda-tion. The subject is provided with two identical, unused kneebands to wear throughout the study. However, if a subject ishaving a degree of discomfort which he or she finds intoler-able, adjust
49、ments in the size can be made, as long as theidentical adjustment is made to both test sites (that is, right andleft knee bands). The knee bands are placed in a separate bagfor each subject, and labeled in a manner that will identify thesubject. One brand of knee bands should be used for allsubjects. A sample worksheet is provided in Appendix X3.12.1.4 Subjects receive an instruction sheet asking them torefrain from using lotions, powders, creams, or skin careproducts in the area behind their knees during their participa-tion in the study (see sample in Appendix X4).
