1、Designation: F1926/F1926M 10F1926/F1926M 14Standard Test Method forEvaluation of the Environmental Stability of DissolutionTesting of Calcium Phosphate Granules, Fabricated Forms,and Coatings1This standard is issued under the fixed designation F1926/F1926M; the number immediately following the desig
2、nation indicates the yearof original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers calcium
3、 phosphate materials intended for use in surgical implant applications.1.2 Aspects of the biological response to calcium phosphate materials in soft tissue and bone have been reported from laboratorystudies and clinical use (1-10).21.3 The requirements of this specification apply to calcium phosphat
4、e materials such as calcium hydroxyapatite (seeSpecification F1185), beta-tricalcium phosphate (see Specification F1088), and biphasic mixtures thereof with or withoutintentional addition of other minor components ( 250 m) shall be spread on a polymeric screen so as to avoid degradation by the stirr
5、ingbar or the overhead stirring mechanism.10. Procedure for Monitoring Changes in pH and Calcium Concentrations10.1 Prepare the test specimen as described in Section 8.10.2 Procure the appropriate volume of dissolution media needed for the experiment and equilibrate at 37 6 0.5C.10.3 Sufficient samp
6、le for at least six replicate tests should be prepared.10.4 Calibrate the pH probe and any other analytical instrumentation to be used immediately before starting the experiment oruse as recommended by the manufacturers.9.4 Calibrate the calcium specific ion electrode as recommended by the manufactu
7、rer except use the same test media as willbe used in the experiment for preparing the calibration standards.10.5 Adjust the stirrer assembly to 100 6 20 rpm.10.6 Assemble the dissolution apparatus (see Fig. 1). The dissolution media, all calibrated sensing electrodes, and the stirrershould be in pla
8、ce and operating. However, do not include the test specimen. Then equilibrate this assembly at 3730 6 0.5C.0.5C.10.7 Record the initial pH of the test media.10.8 Calibrate the calcium specific ion electrode as recommended by the manufacturer except use the same test media forpreparing the calibratio
9、n standards as will be used in the experiment.10.9 Set the experiment timing device to zero.FIG. 23 Test Specimen and CoatingF1926/F1926M 14410.10 When ready to begin the experiment, add the test specimen to the dissolution vessel, and make any necessary adjustmentsto the equipment.10.11 As soon as
10、practical after the introduction of the test specimen to the dissolution media, record the initial pH and the initialdissolved Ca+Ca+ concentration.10.12 Repeat the measurement of the dissolved Ca+Ca+ concentration at appropriate time intervals to define the dissolutionrate curve.10.12.1 A typical i
11、nitial sampling rate is every three minutes or more frequently for the first 15 min. More frequent samplingmay be necessary for some materials in order to accurately determine accurately the slope of the initial linear portion of thedissolution curve.10.12.2 A typical sampling rate for the remainder
12、 of the test is every hour or more frequently and then every 10 min for thelast hour of the experiment.10.13 The duration of a typical experiment shall be at least 24 h. Longer times may be needed for some materials if theirmeasured concentrations of dissolved Ca+ continue to change by more than 10
13、% 10 % over a 1 h 1-h period.10.14 Record the final pH of the test media. If the final pH differs by more than 0.2 pH units from the initial value, this entireexperiment shouldshall be considered invalid. Determine and correct the cause of the change in the pH of the buffered media andrepeat the tes
14、t.10.15 Verify the calibration of the calcium electrode.11. Report11.1 Report the following results for each of the media systems used:11.1.1 All procedural details that differ from those described in this test method.11.1.2 The mass to dissolution volume ratio of the test.11.1.3 The identity of the
15、 dissolution media, the substrate material(s).11.1.4 The pH and concentration of dissolved Ca+ recorded at the start of the experiment (see 9.1010.10).11.1.5 The pH and concentration of dissolved Ca at the end of the experiment (see 9.1310.13).11.1.6 Plots of the concentrations of total dissolved Ca
16、+ versus time data for the duration of the experiment.11.1.7 The calculated initial dissolution rates as follows:11.1.7.1 Calcium phosphates typically display two quasi-linear regions in their dissolution rate curves. The initial dissolutionrate is usually distinguished from the final dissolution ra
17、te by a significantly higher rate of increase in the concentrations ofdissolved Ca+. The final dissolution rate is that rate observed in the quasi-equilibrium state obtained immediately prior to beforethe termination of the experiment.11.1.7.2 The initial dissolution rate (Ri) is expressed in terms
18、of the initial changes in total Ca+ concentration with time. (Ri)Ca= initial slope of the Ca+ concentration versus time curve expressed in terms of the total dissolved Ca+ (in mg) per mg inmilligrams of material per mLmillilitre of dissolution media per hour.11.1.8 The final dissolution rates (Rf) i
19、s expressed in terms of the final changes in total Ca+ concentration with time. (Rf)Ca =final slope of the Ca+ concentration versus time curve expressed in terms of the total dissolved Ca+ (in mg) per mg in milligramsof material per mLmillilitre of dissolution media per hour.12. Precision and Bias12
20、.1 Precision and bias of this test method will be determined after interlaboratory tests are carried out and the results tabulated.The interlaboratory tests will be carried out following Practice E691.13. Keywords13.1 calcium-phosphate ; calcium-phosphate; coating; dissolution rate; environmental st
21、ability; fabricated form; granuleF1926/F1926M 145APPENDIX(Nonmandatory Information)X1. RATIONALEX1.1 Certain concentrations of TRIS have been reported to interfere with the performance of some Ca+2 ion specific electrodes.In order to To minimize or eliminate this potential interference, it is import
22、ant for the user of this test method to conduct all Ca+2ion concentration measurements on calibration standard solutions and working solutions that have equivalent TRIS concentrations.X1.2 Although this test method does not require the measurement, control, or reporting of the calcium phosphate mate
23、rialssurface area, porosity, coating thickness, or coating deposition method, all these parameters are known to affect its measureddissolution rate. Therefore, the user must carefully consider these parameters when attempting to comparingcompare differentcalcium phosphate materials.REFERENCES(1) Cra
24、nin, A. N., Tobin, G., Gelbman, J., and Varjan, R., Trans. Soc. Biomaterials, 1986.(2) Kent, J. N., Quinn, J. H., Zide, M. F., Guerra, L. R., and Boyne, P., J. Oral and Maxillofacial Surg., Vol 41, No. 10, 1983.(3) Yukna, R. A., Mayer, E. T., and Brite, D. V., J. Periodontology, Vol 55, No. 11, 1984
25、.(4) Jarcho, M. P., Kay, J. F., Gumaer, K. I., Doremus, R. H., and Drobeck, H. P., J. Bioengineering, Vol 1, 1977.(5) Drobeck, H. P., Rothstein, S. S., Gumaer, K. I., Sherer, A. D., and Slighter, R. G., J. Oral and Maxillofacial Surg., Vol 42, 1984.(6) Tracy, B. M. and Doremus, R. H., J. Biomedical
26、Materials Research, Vol 18, 1984.(7) Cook, S. D., Kay, J. F., Thomas, K. A., and Jarcho, M., Clin. Orthop., Vol 230, 1988.(8) Kay, J. F., Golec, T. S., and Riley, R. L., J. Prosthet. Dent., Vol 58, 1987.(9) Jarcho, M., Clin. Orthop., Vol 157, 1981.(10) Sendax, V., Dent. Clin. N. Am., Vol 36, 1992.(1
27、1) Hergenrother, P. J., and Martin, S. F., Anal. Biochem., Vol 251, 1997, p. 45.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the val
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