Absorption enhancers mechanisms

Tomita, M., I. M. Hayash, and S. Awazu. Absorption-enhancing mechanism of EDTA, caprate, and decanoylcamitine in Caco-2 cells.,... 

Uchiyama, T., et al. 1999. Enhanced permeability of insulin across the rat intestinal membrane by various absorption enhancers Their intestinal mucosal toxicity and absorption-enhancing mechanism of n-lauryl-beta-D-maltopyranoside. J Pharm Pharmacol 51 1241. 

Tomita M, Hayashi M, Awazu S (1995) Absorption-enhancing mechanism of sodium caprate and decanoylcarnitine in Caco-2 cells. J Pharmacol Exp Ther 272 739-743 Uchiyama T, Yamamoto A, Hatano H, Fujita T, Muranishi S (1996) Effectiveness toxicity screening of various absorption enhancers in the large intestine intestinal absorption of phenol red and protein and phospholipid release from the intestinal membrane. Biol Pharm Bull 19 1618-1621... 

Therefore, the absorption of stearic acid was considerably enhanced due to the presence of DIMES in bile duct-ligated rats. In all probability, the absorption enhancing mechanism of DIMES differs from that of sodium deoxycholate. 

The preparation and properties of a novel, commercially viable Li-ion battery based on a gel electrolyte has recently been disclosed by Bellcore (USA) [124]. The technology has, to date, been licensed to six companies and full commercial production is imminent. The polymer membrane is a copolymer based on PVdF copolymerized with hexafluoropropylene (HFP). HFP helps to decrease the crystallinity of the PVdF component, enhancing its ability to absorb liquid. Optimizing the liquid absorption ability, mechanical strength, and processability requires optimized amorphous/crystalline-phase distribution. The PVdF-HFP membrane can absorb plasticizer up to 200 percent of its original volume, especially when a pore former (fumed silica) is added. The liquid electrolyte is typically a solution of LiPF6 in 2 1 ethylene carbonate dimethyl car-... 

LeCluyse. In vitro and in vivo analysis of the mechanism of absorption enhancement by palmitoylcamitine.,... 

Muranishi, S., Yamamoto, A., Mechanisms of absorption enhancement through gastrointestinal epithelium, in Drug Absorption Enhancement, de Boer, A. G. (ed.), Harwood Academic Publishers, 1994, 67-100. 

Hochman, J., Artursson, P., Mechanisms of absorption enhancement and tight junction regulation, J. Controlled Release 1994, 29, 253-267. 

Sjosteom, M., Lindfors, L., Ungell, A. L., Inhibition of binding of an enzymatically stable thrombin inhibitor to lumenal proteases as an additional mechanism of intestinal absorption enhancement, Pharm. Res. 1999, 26, 74-79. 

In situ intestinal mechanisms (e.g., polarity in transport) Evaluation of absorption enhancing strategies on a mechanistic basis Well-defined absorptive area Good oxygenation Closest model to in vivo Implies anesthesia and surgery... 

Marttin, E., Verhoef, J. C., and Merkus, F. W. H. M. 1998. Ef cacy, safety and mechanism of cyclodextrins as absorption enhancers in nasal delivery of peptide and protein dtdgsug Target. 6 17-36. 

Lindmark, T., et al. 1997. Mechanism of absorption enhancement in humans after rectal administration of ampicillin in suppositories containing sodium caprate. Pharm Res 14 930. 

Lindmark, T., T. Nikkila, and P. Artursson. 1995. Mechanisms of absorption enhancement by medium chain fatty acids in intestinal epithelial Caco-2 cell monolayers. J Pharmacol Exp Ther 275 958. 

Takahashi, H., et al. 1997. The enhancing mechanism of capric acid (CIO) from a suppository on rectal drug absorption through a paracellular pathway. Biol Pharm Bull 20 446. 

The most efficient rectal absorption enhancers, which have been studied, include surfactants, bile acids, sodium salicylate (NaSA), medium-chain glycerides (MCG), NaCIO, enamine derivatives, EDTA, and others [45 17]. Transport from the rectal epithelium primarily involves two routes, i.e., the paracellular route and the transcellular route. The paracellular transport mechanism implies that drugs diffuse through a space between epithelial cells. On the other hand, an uptake mechanism which depends on lipophilicity involves a typical transcellular transport route, and active transport for amino acids, carrier-mediated transport for (3-lactam antibiotics and dipeptides, and endocytosis are also involved in the transcellular transport system, but these transporters are unlikely to express in rectum (Figure 8.7). Table 8.3 summarizes the typical absorption enhancers in rectal routes. 

---