Investigation of the release behavior of cupric ion for three types of Cu-IUDs and indomethacin for medicated Cu-IUD in simulated uterine fluid

BackgroundA number of copper-bearing intrauterine devices (Cu-IUDs) are now commercially available in China. The release behavior of cupric ion from Cu-IUDs is essential to the success of contraception, and the release behavior of indomethacin from medicated Cu-IUD is related to its therapeutic effect.Study DesignIn this study, analytical methods were established to investigate the release behavior of cupric ion of three existing types of Cu-IUDs and indomethacin of one medicated Cu-IUD (Yuangong 365 Cu-IUD). Cu-IUDs were incubated in simulated uterine fluid (SUF). The concentrations of cupric ion and indomethacin were analyzed by flame atomic absorption spectrometer (FAAS) for 250 days and UV 752 spectrophotometer for 300 days, respectively.ResultsThe release behavior of cupric ion for three types of Cu-IUDs was biphasic, which consisted of the initial burst release and then slow and constant release. The release of cupric ion from the medicated Cu-IUD Yuangong 365 showed a zero-order process. In vitro release experiment confirmed a sustained release of indomethacin from Yuangong 365 and the release was in accordance with the Weibull equation.ConclusionThe cupric ion release appears to be more constant in the medicated Cu-IUD than in the others. In view of the feature of indomethacin release from medicated Cu-IUD, it is conjectured that the design of this device could be useful to avoid the adverse effects caused by all Cu-IUDs.