Anal. Chem. 2006, 78, 5607-5608
Correspondence
Comments on Total Platinum Concentration and Platinum Oxidation States in Body Fluids, Tissue, and Explants from Women Exposed to Silicone and Saline Breast Implants by IC-ICPMS Thomas H. Lane*,†
Dow Corning Corporation, 2200 W Salzburg Road, Midland, Michigan 48686
The paper by Lykissa and Maharaj (Lykissa, E. D.; Maharaj, S. V. M Anal. Chem. 2006, 78, 2925-2933) purports to provide evidence that the urine of women with silicone breast implants contain 60 to over 1700 times more platinum in their urine that the urine of people with no known exposure to platinum. Further, they purport to show evidence that the platinum used in the manufacture of breast implants (Pt0) is converted by a unknown process to yield highly oxidized platinum species, stable in biological matrixes, up to and including Pt6+. This correspondence poses three questions associated with the work and directs the reader’s attention to the data, which clearly show that the blood and urine platinum levels in implanted women and their healthy control group were not significantly different from one another. The article by Lykissa and Maharaj1 begs several interesting questions that were not sufficiently addressed in the original paper. Specifically, there are three major questions which, if answered, would help the reader understand the relevance of this work to the breast implant controversy. (1) Is platinum from a breast implant available for systemic distribution within the body? Silicone gel and salinebased implants do contain catalytic amounts of platinum in the zero oxidation state.2 Typically, the silicone gel would contain ∼1 ppm platinum while the shell, which is more highly cross-linked, would contain ∼10 ppm platinum.3 A typical 300-cm3 silicone breast * Fax: +1 (989) 496-5956. Tel: +1 (989) 496-4181. E-mail: tom.lane@ dowcorning.com. † The author has presented the chemistry associated with silicone breast implants at the FDA, The National Academy of Sciences Institute of Medicine, National Institute of Cancer, and several other similar venues. The author has not served as an expert witness in any silicone breast implant litigation. The Dow Corning Corporation has not manufactured silicone breast implants since 1992. (1) Lykissa, E. D.; Maharaj, S. V. M. Anal. Chem. 2006, 78, 2925-2933. (2) Lane, T. H. and Burns, S. A. Silica, Silicon and Silicones...Unraveling the Mystery. In Immunology of Silicones; Potter, M., Rose, N. R., Eds.; SpringerVerlag:New York, 1996; pp 3-12. (3) Bondurant, S.; Ernster, V. L.; Herdmand, R., Safety of silicone breast implants. Institute of Medicine, U. S. Committee on the Safety of Silicone Breast Implants. Washington, DC: IOM, 2000; p 67. 10.1021/ac060759e CCC: $33.50 Published on Web 07/31/2006
© 2006 American Chemical Society
implant might contain a total of ∼300 µg of platinum. The platinum in the device is locked into a cross-linked hydrophobic matrix where it largely remains. The authors, however, argue that the platinum is mobile and that it leaches freely from the device. The authors infer potential health issues for women, despite the findings of the National Academy of Sciences, Institute of Medicine Report,4 which clearly stated that the “...biological plausibility for platinum related health problems in women with silicone breast implants does not presently exist.” It would have helped the reader to understand that many of the assertions made by the authors in their paper have already been the subject of a significant and thorough scientific review. Curiously, the authors seem to dismiss their own data that support the fact that platinum levels in implanted women are not significantly different from those found in the control group. Specifically, the authors state in the Results and Discussion section, “Mean Pt concentration in whole blood samples of women exposed to silicone breast implants and that of control subjects did not show a statistically significant difference.” Further they stated, “Mean Pt concentration in urine samples from women exposed to silicone breast implants and that of control subjects did not show a statistically significant difference.” However, to make their point, the authors appear to have abandoned their control group and compare their experimental data to a collection of published data without an adequate explanation to justify this action (Table 3 from the manuscript). Abandoning their control group and choosing to compare their data with data generated from other analytical methodologies and from other sources without a satisfactory discussion of limits of detection, sensitivity, and interferences is inconsistent with generally accepted practices. The authors may have missed an extremely interesting observation. Analysis of the fill solutions (saline) from the two saline-base implants demonstrate that no platinum migrated from the implant’s shell into the fill liquids even after 18 and 3 years of implantation (cases 2 and 4, respectively.) Total fluid contact time with the device for cases 2 and 4 are not known because the producer’s lot numbers were not correlated to a date of manu(4) Ibid. Ref 3, p 110
Analytical Chemistry, Vol. 78, No. 15, August 1, 2006 5607
facture. An important observation, even if the sample size was two. (2) What is the plausibility that highly oxidized states of platinum could enjoy a sustained existence within a biological matrix and how could they possibly be formed? The authors suggest that there are measurable levels of platinum in oxidation states ranging from zero to plus six (Pt6+) in many of the samples taken from women who had breast implants. The authors do not offer a hypothesis as to how the Pt0 used in the manufacture of silicone breast implants is transformed into the various highly oxidized platinum ions that are reported. Nor do the authors adequately explain how the reported platinum forms might have been affected by the digestion procedure required for the analysis. The authors did not substantiate their premise that the platinum found in the biological samples taken from women who had silicone breast implants could be speciated, by oxidation state, by ion chromatography. To obtain true speciation, one must have standards for the species of interest. This, of course, is difficult in the absence of knowing exactly what the peaks are in this study. LC-MS would have been a good starting place. However, in the absence of standards or a corroborating technique, the authors may be misleading the reader by suggesting that platinum in oxidation states ranging from zero to plus six were found in biological samples taken from women with silicone breast implants. (5) Brook, Michael A, Biomaterials 2006, 27 (17), 3274-3286.
5608
Analytical Chemistry, Vol. 78, No. 15, August 1, 2006
To analyze the samples taken from women with silicone breast implants, the investigators must first digest the samples in a strongly oxidizing acid. No data are offered to help the reader understand the effect of this harsh, oxidizing digestion technique on the oxidation state of the samples being analyzed. Is it possible that what the authors are reporting in this paper is an artifact of the digestion procedure? (3) Why do the authors devote so much column space to a discussion of chloroplantinates? The platinum catalysis used in the production of silicone breast implants is platinum zero complex, not a chloroplatinate. Much of the relevant chemistry associated with breast implants, including the platinum-catalyzed hydrosilylation reaction used for breast implants was recently reviewed by Brook5 in an article entitled, Platinum in Silicone Breast Implants. In summary, the authors’ primary conclusions are not supported by their own data. They did, however, observe that blood and urine samples of women exposed to silicone breast implants and that of control subjects did not show a statistically significant difference in platinum levels. A complete discussion of why the authors abandoned their control group would have helped the reader put this work into a proper perspective.
Received for review April 21, 2006. Accepted May 30, 2006. AC060759E
