Emulsions intestinal absorption from

Kimura, T., Takeda, K., Kageyn, A., Toda, M., Kurpsaki, Y., and Nkayama, T. (1989), Intestinal absorption of dolichol from emulsions and liposomes in rats, Chem. Pharm. Bull, 37,463-466. 

Kakemi and co-workers have studied the mechanisms of intestinal absorption of drugs from O/W emulsions extensively using in vitro and in vivo models. In their first paper [220] on the topic they use as their starting point the equation of Bean and Heman-Ackah [221] derived for a preservative-emulsion system in which the concentration of active agent in the aqueous phase was related to the overall concentration in the system... 

Sorbitan sesquioleate emulsions of petrolatum and wax are used as ointment vehicles in skin treatment. In topical appHcations, the inclusion of both sorbitan fatty esters and their poly(oxyethylene) derivatives modifies the rate of release and promotes the absorption of antibiotics, antiseptics, local anesthetics, vasoconstrictors, and other medications from suppositories, ointments, and lotions. Poly(oxyethylene(20)) sorbitan monooleate, also known as Polysorbate 80 (USP 23), has been used to promote absorption of ingested fats from the intestine (245). 

Irrespective of the physical form of the carotenoid in the plant tissue it needs to be dissolved directly into the bulk lipid phase (emulsion) and then into the mixed micelles formed from the emulsion droplets by the action of lipases and bile. Alternatively it can dissolve directly into the mixed micelles. The micelles then diffuse through the unstirred water layer covering the brush border of the enterocytes and dissociate, and the components are then absorbed. Although lipid absorption at this point is essentially complete, bile salts and sterols (cholesterol) may not be fully absorbed and are not wholly recovered more distally, some being lost into the large intestine. It is not known whether carotenoids incorporated into mixed micelles are fully or only partially absorbed. 

Milk fat globule membrane (MFGM) emulsion was shown to enhance the absorption of epidermal growth factor (EGF) from the intestine, especially to intestinal lymph. The oral bioavailability of propanolol was shown to increase when administered in oleic acid and other lipid media. It is thought that the oleic acid forms an ion-pair with the drag and the entire complex is incorporated into chylomicrons. A further factor in the absorption enhancing effects may be that oleic acid per se stimulates chylomicron production. 

In animal studies, absorption of vitamin D [102] and E [103] has been shown to depend on the presence of bile salts in the intestine. In rats, a polar lipid, oleic acid, is absorbed almost as well from an emulsion as from a micellar solution while a-tocopherol uptake from an emulsion was much less than from a micellar solution... 

Foranulationscifwettable powders, suspensions, and emulsions can affect the retention rate on hair and skin ex the absorption rate from die intestine. 

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