“Degradation control of intrauterine devices (IUD) by using organic corrosion inhibitors”

FLORENCIA ALVAREZ; MARIA DOLORES PEREDA; PATRICIA L. SCHILARDI; MONICA FERNANDEZ LORENZO DE MELE

Maratea

Simposio; 2nd Symposium on Biodegradable Metals; 2010

Copper intrauterine devices (Cu-IUDs) are one of the most cost-effective reversible methods to prevent pregnancy, mainly for long-term use. Their contraceptive effect is based on copper ions release from the copper wire of these devices. However, the dissolution rate change with time: in the first month after insertion the IUDs release up to 4.7 umol of copper daily and decreases to 0.16-0.63 umol daily after 3-5 months. In fact, the concentration of copper in the uterus varies and is higher at short distances from the IUD.  Over-exposure could produce a wide spectrum of effects on surrounding cells and may induce endometrium damage.  Previous studies of our laboratory evidenced cytotoxicic and genotoxic effects of copper ions at the concentration range associated to the first days after immersion. With the aim of reducing copper dissolution organic compounds (thiourea and purinne) were assayed as weak corrosion inhibitors. Thiourea was selected because of its corrosion inhibition properties and its possible benefit action against copper-induced oxidative damage. Purinne has recently been proposed as biocompatible corrosion inhibitor. The electrochemical behaviour of copper in the presence and in the absence of the organic compounds was followed by conventional electrochemical techniques.  Results showed both compounds adsorbs on the copper surface being  the copper ions release rate dependent on the concentration of the organic inhibitors and on the immersion time of the treatment.  A detailed analysis of the electrochemical response is needed in each case in order to select the appropriate conditions adequate for IUD that is: sufficient copper ions concentration to ensure the contraception action and controlled dissolution to avoid health problems for the users. The application of Cu-IUD treated with biocompatible corrosion inhibitors seem to be promissory to reduce local and systemic effects of copper ions.