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Keywords
Copper, Corrosion, Medical products
Abstract
A corrosion study of the intra-uterine device, "TCu 380 A", was made using cyclic voltammetry (CV), scanning electron microscopy (SEM) and optical microscopy (OM). Blood plasma, whole blood and artificial uterine fluid were used as corrosive media in order to establish a comparative scheme of the corrosion behaviour of copper in the device. In summary, the results obtained were not only similar to work reported previously, but also provided complementary data for a better understanding of the corrosion problem.
1. Introduction
One of the most popular contraceptive methods used in Mexico and around the world is the "TCu 380 A"-type intrauterine device. Family planning programmes launched by public health institutions have promoted the use of this copper IUD and the use of an IUD is the most popular method of postpartum contraception in Mexico (Family Health International, 1985). It is known that the contraceptive effect depends mainly on the copper ions released as consequence of copper corrosion in uterus (Holland and White, 1988; Ortiz et al., 1996; Roblero et al., 1996). Because corrosion limits the efficiency and time of use of the device, some studies have focused on the rate of copper release in vivo and in vitro (Bastidas and Simancas, 1997; Kjaer et al., 1993; Kosonen and Thiery, 1983; Thiery and Kosonen, 1987; Timonen, 1976). Generally, two events of the copper degradation (mainly wire fragmentation) in uterus are accepted: first the accelerated release of copper by the influence of pH and deposition of corrosion products (Bastidas et al., 2000, 2001; Mora et aL, 2000; Yuan et al., 1986), and secondly the deposition of proteins, anti-inflammatory agents, blood, cell debris and calcification (Rizk et aL, 1990; Valdez et al., 2000; Xue et al., 1998; Zhu et al., 1999). The oxygen concentration dissolved in the uterine fluid is another factor that affects the rate of IUD degradation due to copper corrosion. Oxygen enters the uterine cavity through the cervix, which is consistent with the location of the most severe corrosion zone on the copper device. The depolariser effect of oxygen has been demonstrated to increase corrosion of IUD materials and dental amalgams (Greener and Matsuda, 1985; Zhang et al., 1996). This study utilised an electrochemical characterisation...