Colon-specific delivery

KRISHNAIAH Y S, SEETHA DEVI A, NAGESWARA RAO L, BHASKAR REDDY P R, KARTHIKEYAN R S, SATYANARAYANA V (2001) Guat gum as a carrier for colon specific delivery influence of metronidazole and tinidazole on in vitro release of albendazole from guar gum matrix tablets. J Pharm Pharm Sci. 4 235-43. 

A second example is the colon-specific delivery of glucocorticoids linked to dextran via a succinic acid or glutaric acid spacer [256a]. Such conjugates resist hydrolysis in the upper gastrointestinal tract, but are rapidly degraded by bacteria in the colon and caecum where little drug absorption occurs. 

K. Uekama, K. Minami, F. Hirayama, 6A-0-[(4-Biphenylyl)-acetyl]-a-, -/3-, and y-cy-clodextrins and 6A-Deoxy-6A-[[(4-biphenylyl)-acetyl]amino]-a-, -/T, and y-cyclodex-trins Potential Prodrugs for Colon-Specific Delivery ,./. Med. Chem. 1997, 40, 2755-2761. 

The same strategy was applied in colon-specific delivery of two corticosteroids used to treat inflammatory bowel disease [20][21], Indeed, budeso-nide /3-D-glucuronide and dexamethasone /3-D-glucuronide underwent ready hydrolysis in the luminal contents of rat colon and caecum. Rat mucosal homogenates were less active, and hydrolysis in human fecal samples was quite low. Based on these and other studies, the prodrugs were found to be suitable candidates for delivery of corticosteroids to the large intestine. 

Macleod, A.D., Tolentino, L., and Tozer, T.N., Glucocorticoid-dextran conjugates as potential prodrugs for colon-specific delivery steady-state pharmacokinetics in the rat, Biopharm. DrugDisp., 15 151-161 (1994). 

Sakuma S, Lu ZR, Kopeckova P, Kopecek J. Biorecognizable HPMA copolymer-drug conjugates for colon-specific delivery of 9-aminocamptothecin. J Control Release 2001 75(3) 365—379. 

Fetih, G., et al. 2005. Improvement of absorption enhancing effects of /j-dodecyl-beta-D-maltopyr-anoside by its colon-specific delivery using chitosan capsules. Int J Pharm 293 127. 

A. N. Fisher, L. Ulum, S. S. Davis, W. Haresign, J. Jabbal-Gill, and M. Hinchcliffe, Use of a Pig Model for Colon Specific Delivery of Peptides, Proteins and Other Drugs, European Symposium on Formulation of Poorly-Available Drugs for Oral Administration, Editions de Sante, Paris, 1996, pp. 183-186. 

The aim of this section is to illustrate some coating techniques based on physical and physicochemical principles. In addition, for their potentiality, the attention will be then focussed on asymmetric membranes and on membranes devoted to colon-specific delivery systems. 

Attempts have been made to achieve colon-specific delivery of drugs. These include 1) prodrugs and 2) polymers (enteric coated, those that are sensitive to degradation by bacterial enzymes, and matrices and hydrogels susceptible to degradation by bacterial enzymes). 

Ability to maintain a constant drug input in the colon for up to 24 h or to deliver drug over an interval as short as 4 h Oral delivery of peptides and proteins. The system can be used to study colonic absorption in humans prior to development of colon-specific delivery systems. 

Sangalli, M.E. Busetti, C. Maroni, A. Zema, L. Olgiati, V. Giordano, F. Gazzaniga, A. Chronotopic system for colon specific delivery pharmacokinetic and scintigraphic evaluation. Proc. Int. Symp. Control. Rel. Bioact. Mater. 1998, 25, 858-859. 

Gazzaniga, A. lamartino, P. Maffione, G. Sangalli, M.E. Oral delayed-release system for colonic specific delivery. Int. J. Pharm. 1994, 108, 77-83. 

Tozaki H, Fujita T, Odoriba T, et al. Colon specific delivery of R 68070, a new thromboxane synthase inhibitor using chitosan capsules therapeutic effects against 2,4,6-trinitrobenzene sulphonic acid-induced ulcerative colitis in rats. Life Sci 1999 64 1155-1162. 

Sriamornsak P, Nunthanid J, Wanchana S, Luangtana-Anan M. Composite film-coated tablets intended for colon-specific delivery of 5-aminosalicylic acid using deesterified pectin. Pharm Dev... 

Patel GN, Patel GC, Patel RB, et al. Colon-specific delivery. Oral colon-specific drug delivery an overview. Drug Deliv Technol 2006 6 62-72. 

Liu ZL, Hu H, Zhuo RX. Konjac glucomannan-graft-acrylic acid hydrogels containing azo crosslinker for colon-specific delivery. J Pharm Sci 2004 42 4370-4378. 

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