Insulin ocular delivery

Pillion DJ, et al. Structure-function relationship among Quillaja Saponins serving as excipients for nasal and ocular delivery of insulin. J Pharm Sci 1996 85(5) 518-524. 

A Yamamoto, AM Luo, S Doddakashi, VHL Lee. (1989). The ocular route for systemic insulin delivery in the albino rabbit. J Pharmacol Exp Ther 249 249-255. 

Morgan, R.V. 1995. Delivery of systemic regular insulin via the ocular route in cats. J Ocul Pharmacol Ther 4 565. 

Sasaki, H. 1994. Effect of preservatives on systemic delivery of insulin by ocular instillation in rabbits. J Pharm Pharmacol 46 871. 

Lee YC, Simamora P, Yalkowsky SH. Effect of Brij-78 on systemic delivery of insulin from an ocular device. / Pharm Sci 1997 86(4) 430-433. 

Hormones, proteins, and small peptides are not suitable for oral administration without complex modifications in the formulation. A variety of approaches for insulin delivery, as a model drug, have been attempted to improve on its bioavailability. Advances have been realized in the delivery of insulin through oral, nasal, rectal, dermatologic, and ocular routes. Proteins can also be delivered transdermally, using a lipid-based, biphasic delivery system in therapeutic quantity. 

Chiou G C Y, Chuang C Y, Chang M S (1989). Systemic delivery of insulin through eyes to lower the glucose concentration. J. Ocular. Pharmacol. 5 81-91. 

In an investigation of the ability of different molecular substances to elicit ocular anaphylaxis when applied topically to the eye, Kahn et al. (1990) concluded that only substances having a molecular weight less than 3500 penetrate the conjunctival barrier. Therefore, systemic delivery via the ocular route seems to rely on overflow of the instilled dmg to the nasal cavity. Thus, the nasal mucosa contributed about 4 times more than the conjunctival mucosa to the systemic absorption of ocularly applied insulin (Yamamoto et al, 1989). Topically applied insulin administered chronically without surfactant seems to be nontoxic to the external human eye (Bartlett etal, 1994a). 

The ocular, buccal, rectal, and vaginal routes of administration all have inherent limitations and serious drawbacks for delivery of insulin and therefore are highly unlikely to be of any use for chronic insulin therapy. 

Lee YC, Yalkowsky SH. Ocular devices for the controlled systemic delivery of insulin In vitro and in vivo dissolution. IntJPharm. 1999 181(l) 71-7. 

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