Abstract: The invention provides an improved device for the injection of medicament such as insulin subcutaneously. The device provides discrete regular injections from an end of a tube containing medicament. The discrete amounts of the injections are programmed to provide a basal injection rate and additional discrete injections can be provided at the user's discretion so that the user has sufficient flexibility to control sudden demands for medicament while nevertheless leaving the basal injection schedule essentially uninteruppted.

Abstract: A tube assembly for a peristaltic pumping system is described. The assembly includes resilient inner and outer tubes of which the inner tube has a lumen along which liquid can be pumped by occluding the tube and causing the point of occlusion to progress along a length of the tube defining a pumping zone. The outer tube fits closely around the inner tube and extends over said zone. The tubes are free of attachment to one another over at least a substantial part of said zone so that the contacting surfaces of the respective tubes define an interface along which relative movement between the tubes can occur during pumping. The tubes are secured together at at least one point along their lengths. It has been found that abrasion of the innermost surfaces of the inner tube is minimized and that reduced contamination of the liquid being pumped and increased pump tube life can be expected as compared with conventional peristaltic pump tubes.

Abstract: An artificial beta cell regulates blood glucose concentration in a subject by continuously analyzing blood from the patient and deriving a computer output signal to drive a pump which infuses insulin at a rate corresponding to the signal. A value of blood glucose concentration from the analyzed blood is used by a computer to determine a rate of change of this concentration which in turn is used to derive a projected blood glucose level. A sigmoidal relationship between the projected blood glucose concentration and the rate of infusion is used to determine the actual rate of infusion required and hence an output signal is fed to the pump to create this actual rate of insulin infusion.