Abstract
Background:
Various insulin delivery systems have been considered for systemic absorption other than injections. Although the ocular route has been suggested, its use is limited by the amount of insulin absorbed systemically via eyes. In order to improve the absorption rate of insulin into systemic circulations, the effects of pH and absorption enhancers were studied with rabbit eyes.
Methods:
Insulin eye drops were instilled into eyes of rabbits, and their blood glucose levels were measured with a Glucoscan 200 Meter (Lifescan, Mountain View, CA).
Results:
Systemic absorption of insulin via the ocular route was much more prominent at higher pH (8.0) than at lower pH (3.5). When absorption enhancers such as glycocholate and fusidic acid were added, the insulin absorption increased further markedly.
Conclusion:
It is feasible to administer insulin through the eyes at pH 8.0 with low concentrations of glycocholate or fusidic acid to achieve the therapeutic efficacy of insulin to lower blood glucose to normal levels.
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