Insulin delivery membranes

Any sol-gel phase reversible system described above can be used as an erodible matrix system. All the components of the system in the sol state are essentially in the dissolved state, and thus they can be released to the environment in the absence of protecting membranes. During the process of gel to sol transition by the addition of glucose, the incorporated insulin can be released as a function of glucose concentration. There are of course other polymeric systems which can be used in glucose-sensitive erodible insulin delivery. 

Cartier S, Horhett TA, and Ratner BD. Glucose-sensitive membrane coated porous filters for control of hydraulic permeability and insulin delivery from a pressurized reservoir. Journal of Membrane Science 1995 106 17-24. 

Further development of the self-regulating insulin delivery system has utilized the complex of glycosylated insulin-concanavalin A, which is encapsulated inside a polymer membrane. As glucose penetrates into the system, it activates the release of glycosylated insulin from the complex for a controlled release from the system (Fig. 28). The amount of insulin released is thus self-regulated by the concentration of glucose that has penetrated into the insulin delivery system. 

Fig. 27 Cross-sectional view of a bioresponsive insulin delivery system, a feedback-regulated drug delivery system, showing the glucose oxidase-entrapped hydrogel membrane constructed from amine-containing hydrophilic pol5mier. The mechanism of insulin release, in response to the influx of glucose, is also illustrated. (From Ref. l)...

Horbett, T.A. Ratner, B.D. Kost, J. Singh, M. A biore-sponsive membrane for insulin delivery. In Recent Advances in Drug Delivery Systems Anderson, J.M., Kim, S.W., Eds. Plenum Press New York, 1984 209-220. 

Figure 5. Basal and augmented insulin delivery rates with various membranes as rate-controlling membranes, using a concentration-difference (100 U/mL) driving force. Peak voltage used as abscissa (R = 80 ft, 30 strokes min, 5 ms on time ) voltage = 0 corresponds to basal rate.

Klumb LA, Horbett TA. Design of insulin delivery devices based on glucose sensitive membranes. J Contr Rel 1992 ... 

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