Control of the release of copper from intrauterine device (IUD) using organic corrosion inhibitors

FLORENCIA ALVAREZ; MARIA DOLORES PEREDA; P. L. SCHILARDI; M. A. FERNÁNDEZ LORENZO DE MELE

Gramado, Brasil

Congreso; 6to Congresso Latino Americano de Orgaos Artificiais e Biomateriais (COLAOB); 2010

The copper intrauterine device (IUD) is a contraceptive method that is basedon the release of copper ions. However, the dissolution rate changes over time: in thefirst month after insertion of the device within the uterus, the release rate of copper ionsis up to 4.7  mol/day and this value decreases to 0.16- 0.63  mol/day after 3-5months. In fact, the concentration of copper within the uterus also varies and is greatestat distances close to the IUD. Overexposure may produce a variety of effects on thesurrounding cells and cause damage to the endometrium. Previous studies from ourlaboratory showed cyto and genotoxic effects of copper ions in the concentration rangeassociated with the first days after IUD insertion. In order to reduce the dissolution ofcopper, organic compounds (such as thiourea and purine) were tested as weakinhibitors of corrosion. The electrochemical behavior of copper in the presence andabsence of these organic compounds was characterized by conventionalelectrochemical techniques. The results show that both compounds are adsorbed on thesurface of copper and that the release rate of copper ions depends on the concentrationof these inhibitors, and on the immersion time for each treatment. Immersions for 60min into solutions in the concentration range of 1x10-2M – 1x10-4M of the organiccompounds prove to be effective, although a better performance was found for purine.Results shows that the application of a copper IUD treated with corrosion inhibitorsthat are biocompatible, is a promising strategy to reduce local and systemic effectscaused by copper ions. However, in each case it will be necessary to perform a detailedanalysis of the electrochemical response to select appropriate conditions for pretreatingthe IUD, to guarantee a sufficient concentration of copper ions to ensurecontraceptive action and simultaneously a controlled release of the copper to avoidhealth problems.