Comparison of the release behaviors of cupric ions from metallic copper and a novel composite in simulated body fluid.

摘要

The copper-containing intrauterine devices (Cu-IUDs) are being increasingly used worldwide as an effective contraceptive for family planning. To avoid abnormal bleeding, pain, and partial and complete expulsion which are associated with the burst release of copper during the first few days, a novel crosslinked composite based on poly(vinyl alcohol) that contained cupric ions, but not metallic copper, was synthesized. It is hypothesized that the burst release of cupric ions could be avoided and the utility of the cupric ions could be improved by this novel composite. To evaluate these effects of the composite, the corrosion products and the release rate of cupric ions after soaking in simulated body fluid (SBF) for different time spans were studied by environmental scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray diffraction, and atomic absorption spectrophotometer. In the first week, the release amount of cupric ions in the composite was 0.486 microg/mm(2). In the fifth week, it decreased to 0.0278 microg/mm(2). But for metallic copper, these were 5.93 microg/mm(2) and 0.041 microg/mm(2), respectively. No significant change on time-dependence was found for the release rates of cupric ions in the composite compared with that of metallic copper. Moreover, no other new elements, such as P, Cl, and Ca, appeared on the surface of the composite, and no Cu2O was formed after immersing in SBF for 90 days. All of these results suggested that burst release of cupric ions could be avoided and the effective utility of copper could be improved in this composite. In view of the earlier results, this novel copper-containing composite might serve as a potential substitute for conventional materials of IUDs in the future.