Contraceptive devices, rubber

A more common contraceptive device is the intrauterine device (IUD). The first type of intrauterine device used was undedicated. These have received increased attention since the use of polyethylene plastics and silicone rubbers [194-196], These materials had the ability to resume their shape following distortion. Because they are unmedicated, these IUDs cannot be classifieds as sustained-release products. It is believed that their mechanism of action is due to local endometrial responses, both cellular and cytosecretory... 

Oil-based lubricants cause failure of rubber condoms and contraceptive diaphragms many lubricants, e.g. hand or baby creams, wash off readily, but are nevertheless oil-based. Barrier contraceptive devices made of polyurethane, e.g. the female condom (femidom), are not so affected. 

Table 17. Contraceptive devices for rubber-sensitive individuals ...

This is a simple nonelectric delay device, but it will not work reliably at temperatures below 40 Fahrenheit. The time delay will depend upon temperature and the thickness of the rubber barrier used. At 70° a rubber contraceptive will provide a delay of 15 to 20 minutes. A rubber balloon, being thicker, will provide a longer delay. 

The most well known commercial reservoir controlled release systems deliver hormones for contraception from hydrophobic polymers. The Norplant subcutaneous device controls the release of levonorgestrel with silicone rubber, and the Progestasert intrauterine device (lUD) releases progesterone from reservoir devices of ethylene vinyl acetate. In the field of insecticides, reservoir dispensers called BioLure were developed to provide zero-order release ofinsect pheromones to disrupt mating (Smith et al, 1983). The dispenser consists of a slab configuration with a rate-controlling membrane, with constant release described by Eq. 1. 

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