Cyclodextrins drug absorption, enhancement

Marttin, E., J.C. Verhoef, and F.W.FLM. Merkus. 1998. Efficacy, safety and mechanism of cyclodextrins as absorption enhancers in nasal delivery of peptide and protein drugs. J Drug Target 6 17. 

Watanabe, Y., et al. 1992. Absorption enhancement of polypeptide drugs by cyclodextrins. I. Enhanced rectal absorption of insulin from hollow-type suppositories containing insulin and cyclodextrins in rabbits. Chem Pharm Bull 40 3042. 

In this chapter, we especially focus on the strategies for enhancement of rectal absorption of various drugs including peptides and proteins from rectal mucosa using pharmaceutically useful excipients, cyclodextrins (CyDs), and the other absorption enhancers. 

CYCLODEXTRINS AS MULTIFUNCTIONAL ENHANCERS FOR RECTAL DRUG ABSORPTION... 

Hovgaard, L., and H. Brondsted. 1995. Drug delivery studies in Caco-2 monolayers. IV. Absorption enhancer effects of cyclodextrins. Pharm Res 12 1328-1332. 

Another type of absorption enhancer, which has been shown to have a better safety profile, is cyclodextrin (CD) [39]. CDs have been shown to form inclusion complexes with lipophilic drugs, thereby improving their aqueous solubility and stability. A powdered insulin formulation containing dimethyl-(3-cyclodextrin improved the absolute bioavailability of insulin by 13% in rabbits compared to a control liquid formulation (1%) of insulin with dimethyl-(3-cyclodextrin [40]. Recently, hydroxypropyl (3-cyclodextrin has been shown to be more effective for enhancing the nasal absorption of acyclovir than a range of other absorption enhancers in vivo [41]. 

Several studies have shown that combinations of cyclodextrins drug complexes and viscosity enhancers can significantly improved ocular absorption [141,236-237] and should therefore be further investigated. 

In eye drop formulations, cyclodextrins form water-soluble complexes with lipophilic drugs such as corticosteroids. They have been shown to increase the water solubility of the drug to enhance drug absorption into the eye to improve aqueous stability and to reduce local irritation. ... 

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]. 

Me, T., Abe, K., Adachi, H. et al. Potential use of 2-hydroxypropyl-(3-cyclodextrin in designing nasal preparations of insulin involving lipophilic absorption enhancer HPE-101. Drug Deliver. Syst. 1992, 7, 91-95. 

It may be said that recent developments in cyclodextrin (CD) applications in drug formulations are concerned with stabilization enhancement of solubility novel preparative methods of inclusion complexes enhancement of bioavailability reduction of topical or hemolytic side effects on administration absorption enhancement in transdermal application. 

Arima, H., et al. 1992. Enhanced rectal absorption and reduced local irritation of the antiinflammatory drug ethyl 4-biphenylylacetate in rats by complexation with water-soluble (3-cyclodextrin derivatives and formulation as oleaginous suppository. J Pharm Sci 81 1119. 

Nakanishi, K., Nadai, T., Masada, M., Masada, M. Effect of cyclodextrins on biological membrane II. Mechanism of enhancement of the intestinal absorption of non-absorbable drug by cyclodextrins. Chem. 

Me, T, Arima, H., Abe, K. et al. Possible mechanisms of cyclo-dextrin-enhanced nasal absorption of peptide and protein drugs. In Minutes of the 6th International Symposium on Cyclodextrins (Hedges, A. R., Ed.). Editions de Sante Paris, 1992, pp. 503-508. 

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