Bioavailability enhancement drug delivery systems

Some of the compounds previously discussed have been used in formulation studies with the eventual aim of enhancing the bioavailability and activity in vivo. The ferrocenyl compounds discussed here are quite hydrophobic, necessitating a drug delivery system. Compounds 4, 5, 7 and 36 were found to create 1 1 water soluble inclusion complexes with methylated (3 cyclodextrin (CD) after stirring overnight. Electrochemical experiments showed that, in methanol, they exhibited a weak interaction with the CD cavity, and that these interactions became stronger as the amount of added water increased, as expected. 

Kang BK, Lee JS, Chon SK, et al. Development of self-microemulsifying drug delivery systems (SMEDDS) for oral bioavailability enhancement of simvastatin in beagle dogs. Int J Pharm 2004 274 65-73. 

Alternative means that help overcome these nasal barriers are currently in development. Absorption enhancers such as phospholipids and surfactants are constantly used, but care must be taken in relation to their concentration. Drug delivery systems, including liposomes, cyclodextrins, and micro- and nanoparticles are being investigated to increase the bioavailability of drugs delivered intranasally [2]. 

Wu, W., Wang, Y. and Que, L. (2006) Enhanced bioavailability of silymarin by self-microemulsifying drug delivery system. Eur. J. Pharm. Biopharm., 63, 288-294. 

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