Controlled release, drug absorption

The notion that bioadhesion enhances the efficiency of drug delivery through an intimate and prolonged contact between the delivery device and the absorption site has resulted in considerable efforts to develop and evaluate bioadhesive polymers. The use of bioadhesive polymers in controlled release drug delivery systems provides potential advantages, including... 

Hussain, A., Arnold, J.J., Khan, M.A., and Ahsan, F. 2004. Absorption enhancers in pulmonary drug delivery. Journal of Controlled Release 94(1), 15-24. 

Junginger HE, Hoogstraate JA, Verhoef JC (1999) Recent advances in buccal drug delivery and absorption—in vitro and in vivo studies. J Control Release 62 149-159... 

J. Wang, Y. Tabata, and K. Morimoto. Aminated gelatin microspheres as a nasal delivery system for peptide drugs Evaluation of in vitro release and in vivo insulin absorption in rats. J Control Release 113 31-37 (2006). 

Borchard G, LueBen HL, De Boer AG, Verhoef JC, Lehr C-M, Junginger HE (1996) The potential of mucoadhesive polymers in enhancing intestinal peptide drug absorption. Ill Effects of chito and carbomer on epithelial tight junctions in vitro. J Control Release 39 131-138... 

Johnson KC (2003) Dissolution and absorption modeling Model expansion to simulate the effect of precipitation, water absorption, longitudinally changing intestinal permeability, and controlled release on drug absorption. Drug Dev. Ind. Pharm. 29 833-842. 

Interferon is the approved treatment for hepatitis C. In general, there are four different treatments (1) IFN-a, (2) combination therapy of IFN-a and another drug called ribavirin, (3) pegylated IFN-a, and (4) pegylated IFN-a with ribavirin. Pegylated interferon contains polyethylene glycol, which increases the half-Ufe (see Section 5.3.5) from 6 hours to 45 hours and slows down the body s absorption of interferon. In this way, a more controlled release of interferon is achieved to prolong absorption. Instead of a subcutaneous injection of three times weekly, the frequency can be reduced to once weekly. 

Fig. 11. Cumulative mean diuresis versus cumulative mean furosemide excretion following 60 mg doses given as two controlled release tablets (boxes), as plain tablets (closed triangles) and following an intravenous dosage of 0.5 mg/kg (open triangles). (From Paintaud G. Kinetics of drug absorption and infiuence of absorption rate on pharmacological effect. Diss. Karolinska Institutet, Stockholm 1993, reproduced by permission.)...

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