5.3.1. Compressed tablets
One attempt to prolong the time range of an insulin dose was reported by Wang et al. in 1987. They made tablets by compressing insulin and cholesterol, and the resulting tablets were implanted under the skin of rats which had been made diabetic by injection of a substance which destroys the islet cells. They showed that the blood glucose levels dropped from a high of about 25 mMolar to below 10 mMolar after implantation. The implant lasted for about 15 - 20 days before a further implant became necessary. The data are shown in figure 5.3.1. The advantage of this type of device is that it is composed of naturally occurring substance, although the advisability of increasing anyone's cholesterol intake might be questioned.
Figure 5.3.1. Blood glucose levels in diabetic rats after implantation of compressed cholesterol/ insulin pellets. Fresh pellets were inserted every 30 days. (after Wang, Implant Diabetes 36:Sept. '87)