Release of copper and indomethacin from intrauterine devices immersed in simulated uterine fluid

Abstract

Objectives To study the release of cupric ions and indomethacin from copper-bearing intrauterine devices (Cu-IUDs) and to assess the influence of their surface area of copper and the pH of the test medium on the release of cupric ions.

Methods Cu-IUDs were incubated in simulated uterine fluid (SUF). The in vitro release of cupric ions and indomethacin was determined by means of a flame atomic absorption spectrometer and a UV 752 spectrophotometer, respectively, over a period of 220 days. The effect of indomethacin on the pH of the SUF was monitored during the cupric ions release study.

Results The Cu-IUDs released cupric ions in vitro according to a biphasic pattern. After an initial burst release, the rate slowed down and then became steady. The release of indomethacin from two medicated Cu-IUDs was biphasic and, in both cases, in accordance with the in vitro dissolution model of the drug. The surface area of copper of Cu-IUDs and the pH change induced by indomethacin incorporated in their frame affected the release rate of copper (p < 0.05).

Conclusion The surface area of the copper and the pH of the test medium modulate the in vitro release of cupric ions from Cu-IUDs.

KEY WORDS:

• Copper intrauterine device (Cu-IUD)
• Medicated copper intrauterine device
• Cupric ion
• Indomethacin
• Release

Acknowledgements

The authors gratefully acknowledge the financial support of the 10th Five Years Key Programmes for Science and Technology 15 Development of China (Serial number: 2004BA720A32) and the 11th Five Years Key Programmes for Science and Technology 16 Development of China (Serial number: 2006BAI15B07).

Declaration of interest: The authors declare no conflicts of interest. The authors alone are responsible for the content and the writing of the paper.