Insulin starch microspheres

A temporary widening of the tight junctions of cultured cells, which coincided with an increase in the rate of absorption of the applied drug, insulin, has been observed in the presence of starch microspheres. It is likely that the dry starch microspheies took up water from the cells causing them to dehydrate and shrink resulting in a separation of the intercellular junctions. Should this be the case, it provides evidence for the paracellular absorption of insulin. 

Biodegradable starch microspheres, 40 pm in diameter, were shown to be capable of enhancing the vaginal absorption of insulin. The effect was further enhanced when the penetration enhancer lysophosphatidylcholine was used. 

Bjork, E., and Edman, P. (1988), Degradable starch microspheres as a nasal delivery system for insulin, Int. I. Pharm., 47,233-238. 

To increase the residence time in the nasal mucosa, a bioadhesive formulation may be one of the most reasonable approaches. In fact, microspheres containing bioadhesive polymers such as starch, albumin, and Sephadex with a particle size of 40-60 pm have been found to be cleared from the nasal cavity much more slowly than solutions. Starch microspheres improved the nasal absorption of insulin, with synergistic effects of some absorption enhancers in sheep. In another paper, dry powder containing starch and Carbopol 974P showed significantly higher bioavailability after nasal administration than the formulation without Carbopol. ° Chitosan, already mentioned above, also has a bioadhesive property and is found to be useful as a potent absorption enhancer for nasal peptide delivery. Other bioadhesive polymer systems,... 

Ilium (1991) demonstrated protein absorption from bioadhesive starch microspheres containing insulin or HGH delivered intranasally in experiments conducted in sheep. 

Grinbeig O, Gedanken A. 2010. The development and characterization of starch microspheres prepared by a sonochemical method for the potential drag delivery of insulin. Macromol Chem Phys 211 924—931. 

Different drug delivery systems have been proposed for vaginal delivery of peptides and proteins. The first one was a mucoadhesive gel based on polyacrylic acid intended for vaginal administration of insulin [96]. More recently, microparticulate systems such as starch and hyaluronan ester (HYAFF) microspheres have been proposed for vaginal delivery of insulin... 

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