Absorption enhancement

The widely used strategies for reducing polymer bandgaps are as follows  

1) Increasing the effective conjugation length by using fused ring system [27-29], conjugated side chain [30-32], or intermolecular interactions [33, 34]. 

2) Incorporation of electron-donating or electron-withdrawing substituent onto the main chain or side chain [35, 36]. 

3) Synthesis of an alternating copolymer from electron-rich (donor) and electron-deficient (acceptor) units in its backbone [37, 38]. 

Strategy can be a very po verful tool to further push the performance of PSCs to the theoretical limit. 

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Absorption of proteins and peptides, which has been reviewed (60), is generally low and somewhat erratic. The judicious use of absorption enhancers may be necessary and can be accomphshed in a very controUed manner in this area. The mouth is routinely exposed to a wide variety of agents of different pH and osmolarity and appears to be more robust than many other epitheha. Exposure to a wide range of pH values produced damage only at the extremes of... 

Hamman et al. [281,282] tested five trimethyl chitosans with different degrees of quaternization as nasal delivery systems the degree of quaternization had a major role in the absorption enhancement of this polymer across the nasal epithelia in a neutral environment. 

Takahara J, Takayama K, Isowa K, Nagai T. Multi-objective simultaneous optimization based on artificial neural network in a ketoprofen hydrogel formula containing o-ethylmenthol as a percutaneous absorption enhancer. Int J Pharm 1997 158 203-10. 

Wu P-C, Obata Y, Fijukawa M, Li CJ, Higashiyama K, Takayama K. Simultaneous optimization based on artificial neural networks in ketoprofen hydrogel formula containing o-ethyl-3-burylcyclohexanol as a percutaneous absorption enhancer. J Pharm Sci 2001 90 1004-14. 

Sun SG, Cai WB, Wan LJ, Osawa M. 1999. Infrared absorption enhancement for CO adsorbed on Au films in perchloric acid solutions and effects of surface structure studied by cyclic voltammetry, scanning tunneling microscopy, and surface-enhanced IR spectroscopy. J Phys Chem B 103 2460-2466. 

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

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

Lindmark, T., Y. Kimura, and P. Artursson. Absorption enhancement through intracellular regulation of tight junction permeability by medium chain fatty adds in Caco-2 cells, J. Pharmacol. Exp. Ther. 1998, 284, 362-369... 

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. 

Quan, Y. S., Hattori, K., Lundborg, E., Fujita, T., Murakami, M., Muranishi, S., Yamamoto, A., Effectiveness and toxicity screening of various absorption enhancers using Caco-2 cell monolayers, Biol. Pharm. Bull. 1998, 21, 615-620. 

Azuma, H., Otagiri, M., Effects of absorption enhancers on the transport of model compounds in Caco-2 cell monolayers assessment by confocal laser scanning microscopy, J. Pharm. Sci. 1997, 86, 779-785. 

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. 

Baluom, M., Friedman, M., Rubinstein, A., The importance of intestinal residence time of absorption enhancer on drug absorption and implication on formulative considerations, Int. J. Pharmaceut. 1998,... 

SDF content is high in fruits, vegetables, and legumes and is associated with colonic degradation and high fermentability, slow glucose absorption, enhanced immune functions, and lower serum cholesterol levels. IDF is predominant in cereals and legumes fermentation is slow and incomplete, and they have more pronounced effects on bowel habit. 

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. 

K. Miyajima, S. Tanikawa, M. Asano, and K. Matsuzaki. Effects of absorption enhancers and lipid composition on drug permeability through the model membrane using stratum corneum lipids. Chem. Pharm. Bull. 42 1345-1347 (1994). 

Ganem-Quintanar A, Quintanar-Guerrero D, Falson-Rieg F, Buri P (1998) Ex vivo oral mucosal permeation of lidocaine hydrochloride with sucrose fatty acid esters as absorption enhancers. Int J Pharm 173 203-210... 

Kitano M, Maitani Y, Takayama K, Nagai T (1998) Buccal absorption through golden hamster cheek pouch in vitro and in vivo of 17/f-estradiol from hydrogels containing three types of absorption enhancers. Int J Pharm 174 19-28... 

Kurosaki Y, TakatoriT, KitayamaM, Nakayama T, Kimura T (1988b) Application of propranolol to the keratinized oral mucosa Avoidance of first-pass elimination and the use of 1 -dodecylazacycloheptan-2-one (Azone) as an absorption enhancer of bioadhesive film-dosage form. J Pharmacobiodyn 11 824—832... 

The major strategies to enhance transmucosal peptide and other drug absorption include (a) coadministration with protease inhibitors, (b) the use of membrane permeation enhancers, (c) coadministration with a combination of absorption enhancers and protease inhibitors, (d) modification of peptide structure to improve metabolic stability or membrane permeation, and (e) use of nano- or microparticles [27], Some of these strategies have been investigated using the in situ rat model. 

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