Comparison of Systemic Absorption of Insulin via Conjunctiva with Punctum Sealed and via Normal Eye with Punctum Opened

It has been reported that insulin eyedrops are useful preparations for delivering insulin systemically. In order to determine the individual contribution of insulin absorption through the conjunctiva and nasal mucosa, experiments were carried out with and without the puncta occluded, while insulin plus absorption enhancer was instilled into the eye. Blood samples were collected at various time points for blood glucose and plasma insulin determinations. It was found that approximately 28-34% of insulin was absorbed via the conjunctiva and 66-72% through nasal mucosa. The blood glucose was lowered significantly more in rabbits with the puncta opened than in those with the puncta occluded.